TABs and Front End Recall Kit

[pezzonovante88]

On average, how many hours of labor would it be for a shop to install new trailing arm bolts and the front-end recall kit?

[Delorean Industries]

On average, how many hours of labor would it be for a shop to install new trailing arm bolts and the front-end recall kit?

Depends on if it is an auto or manual car.

[Cory W]

On average, how many hours of labor would it be for a shop to install new trailing arm bolts and the front-end recall kit?

It's something that wouldn't take a couple of people long to help you with, say on a tech day or something ;)

[pezzonovante88]

Depends on if it is an auto or manual car.

Manual

[pezzonovante88]

It's something that wouldn't take a couple of people long to help you with, say on a tech day or something ;)

Yeah? Okay we'll see I guess.

[jawn101]

Front end recall is like an hour's work, nothing major needs to move for that one. Just the radiator support brackets if I recall, and you can do one at a time to avoid dropping the whole radiator assembly. The castle nuts are pretty easy as well.

TABs are a bit of a pain in the butt but mostly because it's a very tight space. In a manual car it is a lot easier. Another hour, maybe two if you get frustrated :)

[82DMC12]

Front end recall is like an hour's work, nothing major needs to move for that one. Just the radiator support brackets if I recall, and you can do one at a time to avoid dropping the whole radiator assembly. The castle nuts are pretty easy as well.

TABs are a bit of a pain in the butt but mostly because it's a very tight space. In a manual car it is a lot easier. Another hour, maybe two if you get frustrated :)

IF the tabs aren't frozen in place!
Andy

[jawn101]

IF the tabs aren't frozen in place!
Andy

OK, fair enough :)

[Cory W]

Yeah? Okay we'll see I guess.

That's right...you haven't met me yet. ;)

[pezzonovante88]

That's right...you haven't met me yet. ;)

haha I know! You didn't come to the parade! Alright then, we'll see you at tech day (or maybe pre-tech day if we end up doing that).

[Nicholas R]

Is it necessary to remove the manual transmission to do TAB's?

[pezzonovante88]

Is it necessary to remove the manual transmission to do TAB's?

No. if it were, I wouldn't be doing it right now :)

[DMCMW Dave]

Is it necessary to remove the manual transmission to do TAB's?

OTOH if you happen to have the transmission out of the car, it will never be easier, especially if they are frozen...

[micmak]

Nobody seems to considering a hoist! Without a hoist the job is easily twice as long.

......Mike...

[pezzonovante88]

Nobody seems to considering a hoist! Without a hoist the job is easily twice as long.

......Mike...

Exactly Mike. That's why I was thinking about just getting a mechanic to do it. I'll have to think about it.

[micmak]

Exactly Mike. That's why I was thinking about just getting a mechanic to do it. I'll have to think about it.

Save it for Tech day, Mark. You know when and where, right?

......Mike......

[Morpheus]

OTOH if you happen to have the transmission out of the car, it will never be easier, especially if they are frozen...

One of my TABs was so stuck that even 10 tons of force (press) couldn't budge it. A machine shop had to drill out the bolt.

[pezzonovante88]

Save it for Tech day, Mark. You know when and where, right?

......Mike......

Okay, okay :) I know where it is and I can't wait!

[David T]

As pointed out, it is hard to give you an estimate because if they wind up with a bent or stuck TAB it can take a long time. Same for the front end (rusted, broken stripped fasteners). Part of the front recall is to check that there is a cotter pin in the ball joints. If there isn't you have to drill the hole. Might as well check for the other recalls, the inertia switch, and the throttle cable. If it's an early car you might also need the starter mod. You should have the service bulletins and recalls book. Doing an automatic is not so bad. You just have to remove the bolts holding the trailing arm to the rear carrier and let it hang on the brake line. That will give you enough room to get the TAB out. Count the shims and write the # on the frame for each side. DO NOT overtorque the TABS. You will crush the sleeves in the bushings. The torque is in the service bulletins. You can check yourself if you have a bent or stuck TAB. Loosen the nut and rotate the bolt. If it won't turn you are in trouble and if it does turn but the trailing arm moves up and down as you turn it the bolt is bent. If it is very bent it will have to be cut up to get it out.
David Teitelbaum



One of my TABs was so stuck that even 10 tons of force (press) couldn't budge it. A machine shop had to drill out the bolt.

[deloumis]

What are these TABs? I've been reading and seeing it talked about alot lately and I don't have the slightest clue what they are. Just curious

[Jacko]

Trailing Arm Bolt

[John U]

Heres a picture....the bolt actually comes in from the other side of the trailing arm (opposite of the picture)

[EarlHickey]

Heres a picture....the bolt actually comes in from the other side of the trailing arm (opposite of the picture)

How does one determine if the bolts in place have or have not already been replaced?

Where does one find this list of recalls or any other tech service bulletins?

[stevedmc]

How does one determine if the bolts in place have or have not already been replaced?

Where does one find this list of recalls or any other tech service bulletins?

You can determine if the bolts have been replaced by checking them. If the bolts are bent or rusted in place they probably haven't been replaced.

[John U]

How does one determine if the bolts in place have or have not already been replaced?

Where does one find this list of recalls or any other tech service bulletins?

when in doubt, replace the tabs....

here's a good link for service info

http://www.dmcnews.com/bulletins/index.html

[EarlHickey]

when in doubt, replace the tabs....

here's a good link for service info

http://www.dmcnews.com/bulletins/index.html

So the original or suspect hardware has no identifying markings or features?

[Cory W]

So the original or suspect hardware has no identifying markings or features?

Since it's under the car and in a tight spot, you can't really see signs of weakness. It sort of happens without warning.

When it breaks while you're driving, you hear a BANG! followed by little "tinkling" sounds (that's the shims and washers hitting the ground).

The rear of the car drops down on the affected side, possibly rubbing the wheel against a wheel well. You may also lose control of the car, since one rear wheel now is trying to move along its driveshaft axis. If you're lucky, you'll be going straight ahead at low speed and come to a safe stop. Other people have had less success. :(

The only real way to know is to jack up the rear end, loosen the bolt up, and see if you can turn it in place without the trailing arm moving up and down, back and forth. If it is, the TAB is bent and should be replaced. If the TAB was already lose, it should be treated with suspicion (has it stretched?)

Often, the bushings the bolt goes through on the frame should be replaced at the same time. Peace of mind and you're already there.

-TAB failure survivor

[Nicholas R]

I replaced mine recently with the body off and the transmission out and it was STILL a major PITA!

here's a picture showing one that I removed (as well as a new DMCH bolt and a new 12.9 grade TAB)

https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-ash4/s720x720/429662_10100433187256275_21412543_46193433_2173537 75_n.jpg
Talk about some major work to get out.

[Morpheus]

This thread brings up an interesting question:

Since Toby TABS are NLA, (and I'm kicking myself for selling my spare set) what is the best alternative currently on the market? Eventually I will have to purchase a set and I would like to get everyone's opinion.

[stevedmc]

This thread brings up an interesting question:

Since Toby TABS are NLA, (and I'm kicking myself for selling my spare set) what is the best alternative currently on the market? Eventually I will have to purchase a set and I would like to get everyone's opinion.

I think Martin (in the UK) probably has the best set of bolts available but they are about $50 shipped to the USA. If I were to replace my tabs again (I currently have Herveys) I would go with Martin's.

If you are looking to go the cheap route, one guy I know of ordered some 1/2 inch bolts from Amazon.com (along with some movies) and ran a 1/2 inch drill through his trailing arms and frame to make the bolt fit. This route is possible if you want to save a dollar and get some movies for less than the cost of TABS from a vendor.

[Nicholas R]

I think Martin (in the UK) probably has the best set of bolts available but they are about $50 shipped to the USA. If I were to replace my tabs again (I currently have Herveys) I would go with Martin's.

If you are looking to go the cheap route, one guy I know of ordered some 1/2 inch bolts from Amazon.com (along with some movies) and ran a 1/2 inch drill through his trailing arms and frame to make the bolt fit. This route is possible if you want to save a dollar and get some movies for less than the cost of TABS from a vendor.

Ouch, I dont think I would want to compromise the trailing arm bolt sleeve by drilling it out. Besides, unless you are getting grade 9 .5" bolts, I dont think the trade off would be worth it. I'm pretty sure stronger metric bolts are more readily available.

Which ones are Martin selling? All I see are his original 10.9 grade ones.

The one on the right in the picture above is a 12.9 grade bolt I ordered from fastenal (M12x130mm). They had to bring it in (took a day) and it was only like $5 for the pair. The originals and the ones DMCH is selling are all 10.9 grade. Metric 10.9 grade is almost identical to a standard grade 8 bolt (10.9 is a tiny bit stronger). 12.9 grade is another grade even stronger.

Grade 8 yield strength: 130,000PSI
Grade 8 tensile strength: 150,000PSI
Class 10.9 yield strength: 136,000PSI
Class 10.9 tensile strength: 151,000PSI
Class 12.9 yield strength: 160,000PSI
Class 12.9 tensile strength: 177,000PSI
Toby TAB: ∞PSI (seriously though, no idea but it's a lot)

(Also please remember, despite what the lady who works at the ACE Hardware near me thinks, stainless steel hardware is NOT the strongest hardware you can buy. Typically it's comparable to a grade 5, sometimes a little less.)

[EarlHickey]

Is either end of the fastener visible with the car on a lift? Even if it requires a mirror or bore-scope?

I'll check to see what's on mine and get some ARP 12 points if mine has weak junk.

It was allegedly fully restored some years back with very few miles since and it does look very nice underneath although it does have a couple peculiar things that bother me.


BTW... I see the pic of the three fasteners, does that bolt need threads that long? Are any of the thread exposed to shear forces once assembled?

Does anyone have bolt dimensions as well as dimensions of where and what is clamped by it?


Since it's under the car and in a tight spot, you can't really see signs of weakness. It sort of happens without warning.

When it breaks while you're driving, you hear a BANG! followed by little "tinkling" sounds (that's the shims and washers hitting the ground).

The rear of the car drops down on the affected side, possibly rubbing the wheel against a wheel well. You may also lose control of the car, since one rear wheel now is trying to move along its driveshaft axis. If you're lucky, you'll be going straight ahead at low speed and come to a safe stop. Other people have had less success. :(

The only real way to know is to jack up the rear end, loosen the bolt up, and see if you can turn it in place without the trailing arm moving up and down, back and forth. If it is, the TAB is bent and should be replaced. If the TAB was already lose, it should be treated with suspicion (has it stretched?)

Often, the bushings the bolt goes through on the frame should be replaced at the same time. Peace of mind and you're already there.

-TAB failure survivor

[Nicholas R]

You can see both ends pretty easily with the car on the lift, especially if its a manual. If it's an automatic, you should be able to see the ends, but you cannot remove them without removing the transmission. My understanding is there isn't enough space to back the original bolt out, or slide a new bolt in with the transmission in place.

With regard to length, the originals are longer than the ones now available. The ones being sold now are 130mm long and this is what they look like installed:
https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc7/64094_10100433187376035_21412543_46193434_10500669 80_n.jpg

[EarlHickey]

Unless you pay for really good stainless hardware.... hardware store variety is typically grade 3.

I'd think 12mm is rather tiny for this application and now that I've had a peek, Ti doesn't sound bad at all for something seeing big shear loads.

Are any of the threads exposed to shear? That's not a good idea and if so, a 12mm shoulder or stripper bolt seems appropriate even with it's much smaller threads and nuts.


Ouch, I dont think I would want to compromise the trailing arm bolt sleeve by drilling it out. Besides, unless you are getting grade 9 .5" bolts, I dont think the trade off would be worth it. I'm pretty sure stronger metric bolts are more readily available.

Which ones are Martin selling? All I see are his original 10.9 grade ones.

The one on the right in the picture above is a 12.9 grade bolt I ordered from fastenal (M12x130mm). They had to bring it in (took a day) and it was only like $5 for the pair. The originals and the ones DMCH is selling are all 10.9 grade. Metric 10.9 grade is almost identical to a standard grade 8 bolt (10.9 is a tiny bit stronger). 12.9 grade is another grade even stronger.

Grade 8 yield strength: 130,000PSI
Grade 8 tensile strength: 150,000PSI
Class 10.9 yield strength: 136,000PSI
Class 10.9 tensile strength: 151,000PSI
Class 12.9 yield strength: 160,000PSI
Class 12.9 tensile strength: 177,000PSI
Toby TAB: ∞PSI (seriously though, no idea but it's a lot)

(Also please remember, despite what the lady who works at the ACE Hardware near me thinks, stainless steel hardware is NOT the strongest hardware you can buy. Typically it's comparable to a grade 5, sometimes a little less.)


You can see both ends pretty easily with the car on the lift, especially if its a manual.

With regard to length, the originals are longer than the ones now available. The ones being sold now are 130mm long and this is what they look like installed:
https://fbcdn-sphotos-a.akamaihd.net/hphotos-ak-snc7/64094_10100433187376035_21412543_46193434_10500669 80_n.jpg

It appears that threads are indeed exposed to shear, compression and tension.

Screw that and thanks for the pic.

I don't see that too strong of a bolt could be used for this application.

I'll machine some of Ti for mine since it's unlikely PWA1480 will ever be affordable.


Tell me how much shoulder needs to extend from the base of the head to just clear the trailing arm bushing, please.

The more I look at that, the more I see me welding to that frame to support both sides of that pivot bolt.

also, why must that bolt be installed head inboard?

[justlooking]

Ouch, I dont think I would want to compromise the trailing arm bolt sleeve by drilling it out. Besides, unless you are getting grade 9 .5" bolts, I dont think the trade off would be worth it.

I thought Bill had a great idea.

12mm bolt (stock trailing arm bolt) = 13mm clearance hole for close fit (ie you can insert the bolt by hand)

1/2 bolt (what Bill is using) = 33/64 clearance hole for close fit = 13.09mm

Is 0.09mm of removed material really going to compromise the trailing arm? Doubt it. It will provide a much wider range of available bolts, though.

[David T]

You do not necessarily want the strongest bolt you can buy. You can only torque it up to 55 ft/lbs or you will crush the sleeve in the bushing. (Drilling it out to accept a larger bolt will reduce this value). If you really want to inspect your TAB's, first see if it is tight and there are at least some shims. I have yet to see a car that doesn't have at least 1 shim. Next, loosen the nut and rotate the bolt. If it doesn't rotate it is frozen and that is not a good sign. If it does rotate watch the trailing arm for any movement. If the bolt is bent the arm will move noticeably. If the bolt is bent, found to be loose, or frozen it needs to be replaced. You need to remove the trailing arm shields to properly inspect the TAB's. If you find that a TAB is loose and you do not know how many shims were there you will have to have the car aligned. I like to write the # of shims right on the frame so when you inspect you can count the shims to make sure they are all there.
David Teitelbaum




QUOTE=justlooking;54251]I thought Bill had a great idea.

12mm bolt (stock trailing arm bolt) = 13mm clearance hole for close fit (ie you can insert the bolt by hand)

1/2 bolt (what Bill is using) = 33/64 clearance hole for close fit = 13.09mm

Is 0.09mm of removed material really going to compromise the trailing arm? Doubt it. It will provide a much wider range of available bolts, though.[/QUOTE]

[EarlHickey]

A 12mm bolt can be torqued tighter than 55 ft/lbs, the forces the nuts contain are not the problem my eyes see.

I read the Toby Article on the Inconel bolts and his solution appears quite intelligent. Much less likely to bend, fatigue or stretch under the dynamic loads.

Also it appears they had enough actual unthreaded shoulder so as not to have the bushing exposed to threads, as well as though it should be done.

I will look mine over carefully and may go ahead and support them outboard without crunching a single number.

Do you know of any reason why this shouldn't be done or better, should not have been done originally?

I still don't know the length of the required shoulder and it is possible that inconel, hastealloy or Ti shoulder bolts exist to give owners lifetime peace of mind.


You do not necessarily want the strongest bolt you can buy. You can only torque it up to 55 ft/lbs or you will crush the sleeve in the bushing. (Drilling it out to accept a larger bolt will reduce this value). If you really want to inspect your TAB's, first see if it is tight and there are at least some shims. I have yet to see a car that doesn't have at least 1 shim. Next, loosen the nut and rotate the bolt. If it doesn't rotate it is frozen and that is not a good sign. If it does rotate watch the trailing arm for any movement. If the bolt is bent the arm will move noticeably. If the bolt is bent, found to be loose, or frozen it needs to be replaced. You need to remove the trailing arm shields to properly inspect the TAB's. If you find that a TAB is loose and you do not know how many shims were there you will have to have the car aligned. I like to write the # of shims right on the frame so when you inspect you can count the shims to make sure they are all there.
David Teitelbaum




QUOTE=justlooking;54251]I thought Bill had a great idea.

12mm bolt (stock trailing arm bolt) = 13mm clearance hole for close fit (ie you can insert the bolt by hand)

1/2 bolt (what Bill is using) = 33/64 clearance hole for close fit = 13.09mm

Is 0.09mm of removed material really going to compromise the trailing arm? Doubt it. It will provide a much wider range of available bolts, though.[/QUOTE]

[EdR5150]

If it's an automatic, you should be able to see the ends, but you cannot remove them without removing the transmission. My understanding is there isn't enough space to back the original bolt out, or slide a new bolt in with the transmission in place.

It is possible to change the TABs on an automatic car without removing the transmission. I did it: http://www.16908.info/?p=586

[DMCMW Dave]

Do you know of any reason why this shouldn't be done or better, should not have been done originally?

[/QUOTE]

Look at the geometry. The rotation of the trailing arm about the bolt is not completely perpendicular.

[DMCMW Dave]

It is possible to change the TABs on an automatic car without removing the transmission. I did it: http://www.16908.info/?p=586

Agreed. You need to move things around a bit and take the bushings out but it can be done.

[David T]

The bolt is not the limiting factor in torquing the system. Going above 55 ft/lbs will crush the sleeve in the bushing. To remove the left TAB on an automatic you undo the bolts holding the trailing arm to the rear carrier to move the trailing arm enough to remove the bolt. Dave S is correct, all of the forces are NOT in the axial plane of the bolt. The trailing arm rotates around and bends the bolt, not just twists it. For all of the threads about the front suspension, the TAB's are a real 'Weak Link" and need regular inspection. Anyone who really wants to point to a bad engineering choice by Lotus just needs to look at the TAB's.
David Teitelbaum



Agreed. You need to move things around a bit and take the bushings out but it can be done.

[DMCMW Dave]

Going above 55 ft/lbs will crush the sleeve in the bushing.

BTDT. - not a happy experience. Alignment guy conversation:

Him - "it needs about 8 shims to hit spec, is that a problem?"
Me - "something is not right"
Me (later) - "why does the bushing look like a mushroom?

[Nicholas R]

It appears that threads are indeed exposed to shear, compression and tension.

also, why must that bolt be installed head inboard?

The threads are not exposed to shear. The only shearing plane is between the trailing arm and the trailing arm bushing/bracket. That portion of the bolt is unthreaded.*

The head is inboard because with the body on, there is not enough space to put the bolt in from the other direction.

http://www.dmcnews.com/Techsection/images/TAB/2348edit.jpg

Not enough space between the body and frame to slide a 130mm bolt in.

[David T]

Actually the book says no more than 5 shims. If you can't get it to spec by then, something is not right and needs to be fixed. In this case it was the bushing and sleeve.
David Teitelbaum


BTDT. - not a happy experience. Alignment guy conversation:

Him - "it needs about 8 shims to hit spec, is that a problem?"
Me - "something is not right"
Me (later) - "why does the bushing look like a mushroom?

[EarlHickey]

I've no doubt that had Delorean stayed in business, the feds, or class action torts claims, would have resulted in this pivot point being supported as described and likely a more robust bushing sleeve as well as a much larger pivot diameter..

I suspect when I modify mine as such, I may even build two trailing arms that accept more appropriate bushings and likely common "unbreako" brand shoulder bolts in the 3/4" size.

I see the geometry and do not see your assertion as a valid answer as to why it cannot and should not be be properly supported on the outboard side.

I do agree that this execution and design is a failure, regardless if Lotus or Delorean called the shots on the specifics.




Look at the geometry. The rotation of the trailing arm about the bolt is not completely perpendicular.[/QUOTE]

[David T]

I wouldn't call it a failure, that's a bit strong. We didn't see this as a problem area for many years. It IS a weak point and some kind of bolt-on upgrade would be very useful. Toby's bolts were a very good solution. Any "outboard" additional support must be compliant and allow the joint to move in several planes of motion.
David Teitelbaum

[EarlHickey]

Let me rephrase that, there should be no threads chewing on the bushing's ID.

What is the maximum length that can be put in the bushing from inboard and is there any reason why the plate could not be threaded to accommodate a much shorter shoulder bolt?

Precision and complex machining costs are much more affordable today than in the early 80's. Just saying and thinking out loud. If it's possible to insert from inboard and the plate have adequate threads rolled in, that would be nicer and better. Properly shouldered would require precision on the bushing sleeve length while such a design would allowing properly torquing a much larger shoulder bolt, or even the tiny 12.

Also, stack height of the maximum five shims and are there instances where more adjustment would be useful other than a crushed inadequate bushing sleeve?


The threads are not exposed to shear. The only shearing plane is between the trailing arm and the trailing arm bushing/bracket. That portion of the bolt is unthreaded.*

The head is inboard because with the body on, there is not enough space to put the bolt in from the other direction.

http://www.dmcnews.com/Techsection/images/TAB/2348edit.jpg

Not enough space between the body and frame to slide a 130mm bolt in.

[EarlHickey]

The trailing arm swings the arc it swings but the pivot, or "joint", ideally should be positively located. Now if you mean that the outboard brace should be "compliant" so as to not foul the trailing arm swinging through it's arc, I'm with you on that obvious point.

Are there any pre-existing frame holes in nearby proximity? I'd certainly prefer bolt on as to welding. I've not put mine on the lift yet as the car has been done from one end to the other with a new looking underside. I will very soon though.

I still maintain failure, had there been 900,000 of these on the road, this flaw would have already killed and/or injured many, or at least it's unlikely that it wouldn't have if people drove them like they were stolen and a replacement as easy as signing the papers.


btw.... do you see any benefit that may be provided by being able to vary the length of the trailing arm, or any of the other rear links?


I wouldn't call it a failure, that's a bit strong. We didn't see this as a problem area for many years. It IS a weak point and some kind of bolt-on upgrade would be very useful. Toby's bolts were a very good solution. Any "outboard" additional support must be compliant and allow the joint to move in several planes of motion.
David Teitelbaum

[EarlHickey]

More studying.... are you telling me this inboard bushing swivels like a rod end joint and must do so?

http://www.16908.info/wp-content/uploads/2008/06/062608-0304-trailingarm81.jpg

If so, that does make supporting the joint on the outboard a bit more complicated.

I suppose if this is the case, it is time to draw it up in three d and animate it.

[DMCMW Dave]

More studying.... are you telling me this inboard bushing swivels like a rod end joint and must do so?
If so, that does make supporting the joint on the outboard a bit more complicated.

It's been done on the aftermarket stainless frame using a rod end (heim) joint.

http://www.pearce-design.com/PFImprovements.html

No good photos of the overall assembly i.e. holding both ends, but it was there.

[David T]

The joint not only pivots around the axis of the TAB, as the trailing arm moves up and down it is also rotated on it's axis because of the way it is supported by the rear suspension. A Heim joint can accommodate that motion but it will transmit road vibration into the frame unless it is suspended by a compliant (rubber) bushing. It is an area ripe for improvement, let's see what you can come up with. One goal to try and aim for would be to make any mod "bolt-in" so any owner with minimal skills can do it.
David Teitelbaum

[Nicholas R]

Dave Bauerle made some pretty intense TAB reinforcement brackets for a while in the past, though I'm not sure he's doing it any more. I've only ever seen them on one car and they are really impressive. The car belongs to Fluxat88MPH here on the boards. I have no pics but maybe he does.

[EdR5150]

http://www.ohiodeloreans.com/bauerle_brackets.html
10128

[EarlHickey]

I'll just have to draw this up in 3d and observe it in motion.

If anyone beats me to it, tag me.

I'll be tied up for a while with my induction and exhaust projects.

So far, I'm not in love with the factory approach or any of the alternatives.

However, I am not sure if the inboard rubber is merely a sleeved bushing or is it a heim/rose/rodend joint captured in rubber?

[DMCMW Dave]

.

However, I am not sure if the inboard rubber is merely a sleeved bushing or is it a heim/rose/rodend joint captured in rubber?

Simple sleeved bushing, the bolt just goes through the bushing then the trailing arm.
10129
http://store.delorean.com/c-354-5-3-0-rear-suspension.aspx

[EarlHickey]

Simple sleeved bushing, the bolt just goes through the bushing then the trailing arm.
10129
http://store.delorean.com/c-354-5-3-0-rear-suspension.aspx


Thanks for the info. I'll share from my limited knowledge and maybe we'll come up with something.

The bushings used to rubber mount the HD softail swingarm are interesting and can be had of upgraded materials.

Check one out if you have the oem stuff to compare.

What is the life of the oem bushing with it's frail crush-able sleeve AND can you give me the numbers for the alignment shim stack heights as well as confirm if more than five are ever needed for what reasons?

However, I am reasonably sure upon seeing this in motion, a very sexy and much more precise solution exists.

I don't like the idea of that bolt wiggling around in rubber, regardless if rubber mounted on both ends.


Wait.... through the bushing and trailiing arm..... hmmmmmm.... how is the bolt shoulder and head contained inboard? What limits it's movement?

Are graphite'd poly-urethane bushings too stiff and harsh for this joint?


What I am seeing now is that the bolt truly could be a rigidly located stud on the inboard plate and the same function served if the trailing arm is merely isolated via a flexible material.

This makes me see adjustable rod ends in multiple axis to accomplish the very same vibration isolation with very precise locating
Examine the engine/transmission mounts on the Buell. Solid yet isolates like rubber. It will make one scratch their head wondering "HTF" until they get the big picture.

I don't mind sharing what I know and have no intention of measuring how freely I share with any personal financial conflicts.


I promise you some others who are the opposite will make money from some of my notions and at least one will offer me a job.

[DMCMW Dave]

1 What is the life of the oem bushing with it's frail crush-able sleeve?

>>>>Based on my experience in the shop, somewhere between 0 and 31 years, and 10,000 to 100,000 miles. If the bolts bend and/or get loose (i.e. the shims fall out) the bushings fail. If the car is not abused, they last seemingly forever.

2 can you give me the numbers for the alignment shim stack heights as well as confirm if more than five are ever needed for what reasons?
>>>>> Each shim is about .08" and worth a specific number of degrees of toe (see your manual). I've seen cars that "wanted" more than 5 but that typically indicates bad bushings, bent trailing arm, or bent frame.

3 how is the bolt shoulder and head contained inboard? What limits its movement?
>>>>A couple of big fat hardened washers (larger than the bushing diameter so they cannot pull through the frame). See previously cited line drawing. The crazy thing to me is that the bushing is held to the frame by two 8mm bolts. Looks precarious but I've never seen one fail.

4 Are graphite'd poly-urethane bushings too stiff and harsh for this joint?
>>>>Poly bushings are available (no graphite), no personal experience but since they need to flex the worry is that you'll stress the bolts more if they are too stiff. Iconel bolts were available for a while. They would still bend but were much harder to actually break.


5.......and one will offer me a job

Probably not without a real identity:
http://www.channel4.com/programmes/my-name-is-earl/articles/earl-hickey

[David T]

If you use a stud and do not allow for all of the motions imposed on the joint you will just overstress another point and it will fail. As I said, the TAB is not subjected to a "pure" rotation about the axis of the bolt. In designing a joint you want to use shear if possible, it is the strongest type of joint. That is not always possible. You also want to try to limit the # of planes of motion to one if possible, that wasn't done in this case either. It is not quite as simple as just overbuilding this. BTW, that is one approach when a joint is subjected to multiple stresses. That rubber in the bushing allows the joint to flex in all directions and to absorb the rotation of the trailing arm about it's axis. By restraining the joint you will flex the trailing arm. Not necessarily a good thing. The rubber also absorbs road vibration. If you do not use the rubber sleeve/bushing, you must find another way to duplicate these functions. You don't need 3D modeling for this. Watch the trailing arm as it moves all the way up and all the way down.
David Teitelbaum

[EarlHickey]

If you use a stud and do not allow for all of the motions imposed on the joint you will just overstress another point and it will fail. As I said, the TAB is not subjected to a "pure" rotation about the axis of the bolt. In designing a joint you want to use shear if possible, it is the strongest type of joint. That is not always possible. You also want to try to limit the # of planes of motion to one if possible, that wasn't done in this case either. It is not quite as simple as just overbuilding this. BTW, that is one approach when a joint is subjected to multiple stresses. That rubber in the bushing allows the joint to flex in all directions and to absorb the rotation of the trailing arm about it's axis. By restraining the joint you will flex the trailing arm. Not necessarily a good thing. The rubber also absorbs road vibration. If you do not use the rubber sleeve/bushing, you must find another way to duplicate these functions. You don't need 3D modeling for this. Watch the trailing arm as it moves all the way up and all the way down.
David Teitelbaum


From what I am able to see and deduce, there is a fallacy in that the bolt and bushing sleeve presents to the bushing as if the bolt were a shouldered stud. Therefore, the sleeve could realistically be crushed regardless of the fastener torque and merely by driving the car AND the bolt shoulder and head would definitely be in shear inboard. This does not compute completely and I am quite fine with accepting the rubber bushing does indeed allow the wiggling of the trailing arm and the bolt should be studded rigidly as it appears the plate, bolt and bushing sleeves seemingly fails, or doesn't? at doing.

If I am sorely still mistaken, I beg your tolerance and would be grateful if you try another tack at articulating that which I fail to grasp.
I'm truly not trying to be argumentative, just trying to fully grasp what appears simple enough.


"Watch the trailing arm as it moves all the way up and down"........... yeah ok!

However, animated 3d never hurt anyone and consider the idea of multi-plane rod end linkages replacing the entire trailing arm assembly as a bolt up.
I know that it may sound/feel counter-intuitive, to many, that an assembly of nearly solid metal joints can accomplish the same as rubber, but, I'm not pulling your leg at all.

In execution it would be mesmerizing to look at and simply elegant making an alignment very painless.

[EarlHickey]

Probably not without a real identity:
http://www.channel4.com/programmes/my-name-is-earl/articles/earl-hickey[/QUOTE]


Thanks for all the good info and I will get around to getting measurements and sketching up some solid forms.
I doubt I'll take mine apart to do it unless something necessitates that happening.


A reasonable person might likely deduce I don't want anymore of that four letter word stuff than I already have, sometimes I find it gets in the way of many things I really enjoy doing. ;-)

[DMCMW Dave]

Thanks for all the good info and I will get around to getting measurements and sketching up some solid forms.
I doubt I'll take mine apart to do it unless something necessitates that happening.

Common practice is to loosen the nut and attempt to rotate the bolt. If it turns, that's good. If it won't turn, it has rusted to the arm and probably ought to be replaced before it rusts worse, and you can't tell if it's bent. If it's bent, you'll see the trailing arm walk up and down.

[Nicholas R]

You know, when I did mine, one was bent way more than the other. It ended up being the non-bent one that gave me all the trouble trying to remove it. The bent one certainly took some work but mainly just tapping and turning. The other one was rusted in the sleeve and was just a nightmare. Combination breaker bar, impact gun, sledge hammer just to get it to even budge. Good thing I had the body off at the time because I dont think I could have done it with it on.

[EarlHickey]

Ok, so if the tab bolt was instead a stud coming square and perpendicular out of the plate, the bushing would or would not allow the assembly to work fine?

It appears to me it would work peachy, and as intended. Reading and rereading what is posted thus far nurtures confusion or my dementia is wrecking my comprehension.


However for the edification of any present or future readers, it would be nice to have a consensus, amongst the membership, regarding this minor, but important, technical subtlety that can have only one correct answer.

[pezzonovante88]

Do you have to drill to install the recall kit? Are there any step-by-steps on how to install them?

[David T]

I see no advantage to a plate and stud as opposed to the bushing and bolt. In fact, it would be more difficult to replace if it gets bent of "frozen". The other problem is no rubber to absorb vibration. And you still are only allowing the trailing arm to rotate on the axis of the stud and providing no allowance for the trailing arm to rotate on it's axis. That is what wants to bend the bolt.
David Teitelbaum



Ok, so if the tab bolt was instead a stud coming square and perpendicular out of the plate, the bushing would or would not allow the assembly to work fine?

It appears to me it would work peachy, and as intended. Reading and rereading what is posted thus far nurtures confusion or my dementia is wrecking my comprehension.


However for the edification of any present or future readers, it would be nice to have a consensus, amongst the membership, regarding this minor, but important, technical subtlety that can have only one correct answer.

[DMCMW Dave]

Do you have to drill to install the recall kit? Are there any step-by-steps on how to install them?

Generally not unless you break something.

http://www.dmcnews.com/bulletins/SC-03-1.82.html

[pezzonovante88]

Generally not unless you break something.

http://www.dmcnews.com/bulletins/SC-03-1.82.html

Ahah, perfect. Thanks Dave. Unfortunately I won't be able to make it to our tech session in Toronto, so I need to get this stuff done someway else.

[EarlHickey]

I see no advantage to a plate and stud as opposed to the bushing and bolt. In fact, it would be more difficult to replace if it gets bent of "frozen". The other problem is no rubber to absorb vibration. And you still are only allowing the trailing arm to rotate on the axis of the stud and providing no allowance for the trailing arm to rotate on it's axis. That is what wants to bend the bolt.
David Teitelbaum

Viewing this topic as has been discussed in this thread, and others, gives any objective person, who has basic understanding that EITHER

1) it would work if it were studded, even with a massive stud welded to the plate, fitted with a better rubber bushing having an adequate and uncrushable sleeve and even if a modified control arm was required to accept it......... period

OR

2) it would not while somehow a properly torqued, to 55 ft lb and no more, 12mm and strong bolt and nut, with a crush-able bushing sleeve whose dimensional change resulting from even merely over-torquing, affects wheel alignment, does clamp this assembly together, in tension, yet allows enough wet noodle action to allow the control arm to move... and this is how it must work.


AGAIN.......

both scenarios are simply not possible and again......... I am certain that if 2 is actually correct, it is a huge fail and would be recalled by the feds if still in production.

I don't think that 2 is correct. I think the plate assembly could have a massive stud welded to it, a better bushing with a sleeve that could withstand fully torquing the stud's nut without changing dimensions while allowing the trailing arm to move throughout it's full range of motion. If any thrust clearance was needed, the stud could be very precisely shouldered and it could even have torringtons in thrust. If this is the case, a precisely shouldered bolt, torqued to it's full capacity, would also work.

I wasn't suggesting a mere hole through the trailing arm and it pivoting only on the stud. I've gathered that the rubber is needed no matter how bizarre of an approach it truly is to require it for other than for isolation purposes.

I'm not suggesting that there would be some advantage to it being studded, I'm truly trying to gather a consensus of exactly how this assembly functions and I am stating that there very certainly appear to be two opposing views on the subject, of which is mathematically certain to only function one way or the other.

There being conflicting information on this subject, which has indeed endangered people, is most egregious and should be unacceptable amongst those who own one and care.

Let me ask this question and see how many will answer with a simple yes or no. I'll certainly read your following explanations carefully, if offered.


THE QUESTION

Ok, so if the plate had a stud welded to it, let's say it's 12mm, let's say we use a different rubber bushing whose sleeve cannot be crushed and this is done by using slightly less rubber or simply stronger sleeve material, so as to retain the original bushing OD, let's say the 12mm shoulder prevents, or even doesn't prevent, the very adequate sleeve from being crushed, while it runs at zero or less than zero thrust clearance this sleeve will pivot smoothly on the 12mm stud.......

will rigidly anchoring the threaded end of the stud in a bolted or welded on perch/out-rigger present any problem to, or inhibit the motion of, the trailing arm, assuming it does not physically touch the trailing arm throughout it's entire range of motion?

Let's assume the amount of rubber sacrificed to substitute a thicker bushing sleeve is negligible and inconsequential. It's even be the same type of rubber originally supplied in the OEM bushing.

The next question....


If the answer is no, then the bolt on supports/perches/out-riggers shown in this thread, did not need to support the threaded end of the "TAB" bolt in rubber isolators....... correct?

[Rich W]

The answer is not 1 or 2...the answer is 3.

3) http://www.pearce-design.com/PFImprovements.html

[jawn101]

The answer is not 1 or 2...the answer is 3.

3) http://www.pearce-design.com/PFImprovements.html

Now, now Rich... let's not muddy this eloquent discourse with your silly research. Clearly Earl here is the first one in the last 30 years to look at the TAB situation with a critical eye.

A shame Pearce isn't making these anymore, frankly.

[Rich W]

Actually, I thought it would muddy the conversation if I mentioned the "Bauerle Brackets", so I did not mention them.

Although, I guess I just did. My bad, again.

[dmcjohn]

I have a concern about the design of that Pearce trailing arm. I had asked questions about it back in the dmctalk.com days but never got an answer. I should say that I've never seen one in real life, so am only going by pictures on the website and I'm happy to be proven wrong on this if someone can explain to me how this works.

It looks like to me that their design essentially stops the movement in the trailing arm bolt area making it a solid joint rather than one which uses a bushing (which would allow for some movement).

http://www.pearce-design.com/Assets/2006FrameShots/DSCN9372.jpg

The trailing arm is a fixed length, so if it is pivoting on one fixed point (the trailing arm bolt), then at the other end it is moving in an arc.

In a regular DMC, as the rear suspension is compressed, the trailing arm bushing compresses, allowing for the trailing arm to move forwards to compensate/allow for the arc.

If the trailing arm is no longer able to move forwards in the Pearce Design, then these same forces (due to the arc in the rear suspension) must be acting on the upper and lower links instead - essentially trying to push them towards the rear of the car as the suspension gets compressed.

So my question is how this was accounted for in the Pearce design?

It's essentially the same argument regarding turning the front lower control arm into a wishbone while the anti-roll bar is attached. If you completely remove the ability of the front lower control arm to move laterally forwards and backwards, without making a change to the way the anti-roll bar is mounted, then you are putting the system in tension with itself, which could eventually lead to fatigue/failure.

John

[DMCMW Dave]

There bushings on the cups. Not much compliance though.

[dmcjohn]

Right - I see them:

http://www.pearce-design.com/Assets/PictureArmEndApart.jpg

but they would only remove some vibration - they don't look like they would allow much movement.

[dmcjohn]

Presumably, it is only whatever bushing is inside the hemi joint where I've put a red arrow that would allow any movement?


The bigger bushings in the previous picture would not come into it as they only reduce vibration - the bolt head is mounted on the outside of a plate and the nut on the inside of the frame - so the bolt position is fixed as it is in double shear. The only bushing which can allow any relief from tension is the one indicated inside the hemi joint on the trailing arm (if there is a bushing there?)...

[DMCMW Dave]

Presumably, it is only whatever bushing is inside the hemi joint where I've put a red arrow that would allow any movement?


The bigger bushings in the previous picture would not come into it as they only reduce vibration - the bolt head is mounted on the outside of a plate and the nut on the inside of the frame - so the bolt position is fixed as it is in double shear. The only bushing which can allow any relief from tension is the one indicated inside the hemi joint on the trailing arm (if there is a bushing there?)...

The pin that goes through the hiem joint and floats in the bushings and is not touching the bolt heads. The heim joint (at least the one used by Pearce) has zero compliance in the joint itself.

[EarlHickey]

Presumably, it is only whatever bushing is inside the hemi joint where I've put a red arrow that would allow any movement?


The bigger bushings in the previous picture would not come into it as they only reduce vibration - the bolt head is mounted on the outside of a plate and the nut on the inside of the frame - so the bolt position is fixed as it is in double shear. The only bushing which can allow any relief from tension is the one indicated inside the hemi joint on the trailing arm (if there is a bushing there?)...

Inside the rod end joint is a spherical bearing that is likely hardened steel on steel, no rubber, possibly a teflon type seal. I'm too lazy to check how many degrees it will swivel, but it's either 16 or 24 degrees, pretty sure.

Thus far, according to Rich, the answer to The Question is 3, the stock configuration does not work at all, because if it works at all, it has to work as described in 1 or 2.

Again, the trailing arm could indeed be done completely with rod joints on adjustable linkages, in multiple axis, allowing it to move any way it needs to, while isolating vibration sans without using any rubber bushings.

That may just sound completely impossible to some.

I've drawn it in 3-D and animated it if you guys want to stop clowning about and get serious. Some of you are mistaken in your theory of how this works and does not work. It's quite simple.

[dmcjohn]

I see that pin, but I'm assuming it is hollow to allow the bolt pass through it?

So if the bolt is passing through that pin, the pin is in direct contact with the bolt. The bolt can't move due to being in double shear, therefore the pin also can't move. Therefore, there is zero compliance in the whole unit in the trailing arm bolt area? Is that correct?

[dmcjohn]

Hi Earl,

I only saw your post now for some reason - I didn't see it when posting my last reply to Dave.

My question is a bit of a moot point at this stage because Pearce is no longer making these trailing arms. However, it does seem to me that the Pearce design is a poor design and causes a bigger problem than the one it tries to resolve.


I've drawn it in 3-D and animated it if you guys want to stop clowning about and get serious. Some of you are mistaken in your theory of how this works and does not work. It's quite simple.

Ok great - post the 3D animation then?

[DMCMW Dave]

I see that pin, but I'm assuming it is hollow to allow the bolt pass through it?

So if the bolt is passing through that pin, the pin is in direct contact with the bolt. The bolt can't move due to being in double shear, therefore the pin also can't move. Therefore, there is zero compliance in the whole unit in the trailing arm bolt area? Is that correct?

FWIW The bolt does not pass through (or touch) the pin. There are two short bolts that thread into the cups from either end. The pin floats in the rubber bushings.

[dmcjohn]

Ah, didn't know there were two bolts involved. Have you any better pictures of the assembly than what I can see on the website?

Thanks,
John

[DMCMW Dave]

Ah, didn't know there were two bolts involved. Have you any better pictures of the assembly than what I can see on the website?

Thanks,
John

Sorry, no. We've assembled one of them and I didn't think to take that level of detail in photos. I do recall it being something of a PITA to assemble and even more to align.

[EarlHickey]

Hi Earl,

I only saw your post now for some reason - I didn't see it when posting my last reply to Dave.

My question is a bit of a moot point at this stage because Pearce is no longer making these trailing arms. However, it does seem to me that the Pearce design is a poor design and causes a bigger problem than the one it tries to resolve.



Ok great - post the 3D animation then?

The Pearce Design is far from optimal as is the original and it does leave much to be desired.

The Buehre (or however it's spelled) lacks proper teeth to be useful.

Several in this thread do indeed propagate mis-information about how this simple assembly does or does not work.

Toby's assessment of it is spot on correct and anyone who doesn't agree with it is wrong.

His solution is based on working with what is there, not fixing it as the Feds would have stepped in and forced DMC to do had they stayed in business.

I have no idea who the moderators are (grown men or children even) or who they may be financially aligned with and I'm simply not going to hand my work over for them to approve it's being shared or not.

So if you know who they are and where their bread is buttered, let me know and I'll decide if I'll freely share it here on this forum which seems plagued by various financial conflicts and small mindedness preventing plain truth from being openly shared.

Otherwise, I'll let you know if I put my website back up or any of my writing on this subject is published in the shiny pages. The second is a certainty.

[dmcjohn]

Ok, thanks Dave.