Dancing speedometer and then zero mph

[Kenny_Z]

So after my close call yesterday I had the radio off to give my brain time to burn off the adrenaline. While it was off I could hear a light brushing noise from the driver's side footwell. It was barely audible over the cabin noise but I could tell it changed with speed. I figured it had something to do with the speedometer and made note to check it this weekend. My speedometer hasn't bounced or done anything odd since I've owned Red. This morning on the way into work my speedometer started bouncing randomly. About a minute into this it just dropped to zero and stayed there for the rest of my drive into work. I've searched the forum but I can't really figure out where to start looking.

[Farrar]

Check every join in the speedometer cable, the angle drive, and behind the dust shield at the front left wheel. Could be something's come loose.

[Chris Burns]

My 1st car did the same thing. I had to tap on the dash to get it to work sometimes. Yea, just check the angle drive and the speedominter cables.

[jawn101]

Well, the brushing sound was likely the dust cap under the driver's side wheel. I'd start there since it's nice and easy - it could have come loose or perhaps the speedo cable rounded off inside of it. Have you ever heard that noise before or was it brand new? If I listen carefully, I can always hear that cap spinning.

The speedo system is pretty simple - dust cap, angle drive, 2 speedo cables, lambda counter, and the gauge itself. It isn't too hard to troubleshoot - use a power drill to slowly spin the different components (insert the end of the cables/angle drive into the chuck), working from the dust cap inward and see where it starts failing.

[DMC5180]

Check every join in the speedometer cable, the angle drive, and behind the dust shield at the front left wheel. Could be something's come loose.

Broken not come loose.

Pull left wheel and see if the cable comes out from behind the dust cap.

[stevedmc]

There are several things that can cause your problem. More than likely it could be anything.

First, the plastic dust cap has a habit of coming loose. Remove the dustcap and wrap some electrical tape around the part that goes in the wheel. This will help keep it from slipping.

Before you reinstall it, inspect the square hole where the angle drive's shaft goes into it. If it is rounded the shaft won't be able to reliably turn. You can either red neck it with some epoxy or call up your favorite vendor such as DMCMW to order a new dust cap. I don't think Hervey sells the dust caps.

The next thing you need to check is to see if the angle drive is actually turning. This is simple actually. Simply disconnect the cable running from the angle drive to the firewall and look at the inside of the angle drive while you turn the shaft. If it turns, you probably have a good angle drive. The reason I say probably is because I noticed on my last angle drive from DMCH that the shaft was a little short. Because it was a little short it wasn't able to fully extend into the dust cap and wouldn't turn. I replaced it with one of Hevey's with a longer shaft and my problem was fixed.

If things are good at the angle drive then reconnect the cable to the angle drive and put the dust cap back on. Disconnect the cable from your speedometer and have someone turn the wheel. Inspect the cable to see if the shaft in it turns. If it turns, your angle drive is good. If it doesn't turn you could have an issue with the connections going to the lambda box or connection issue in the dustcap. You can bypass the box with a longer cable from Hervey if you desire. You don't need it because all it does is turn on the service light every 30k miles.

Here is the combination that works for me:
Hervey's long speedometer cable
Hevery's angle drive
DMCH (Ordered from DMCMW) dust cap

I've been running this setup combined for at least 6 months (and probably 6k miles) with no issues.

[David T]

While you are going through the speedometer drive system be sure to lube the angle drive. If it gets hard to turn it causes the inner core to the dust cap to unwind and the dust cap square hole to round out.
David Teitelbaum

[Kenny_Z]

Thanks everyone, I'll start at the wheel and work my way back. It seems like a simple system. Looks like it is a lot easier to get to than the ones in my other cars.

[Michael]

The two things I can see as the probable cause:

As mentioned, the dust cap has become loose(either inside where the cable sits, or spinning on the outside), and/or you have tightened the lambda box(where the two cables meet) too tight. The cable couplings need to be finger tight only, any tighter and it will bind up. If this is the case, it probably stripped out the inside of your dust cap so be sure to check that before replacing the cap or it will just do it again.

[orbitron3000]

Not trying to hijack this thread, but I am having a similar problem as Kenny_Z. Only difference was the speedometer needle would bounce between 0 and 20-25 mph, and then be steady afterwards. After a few months of regular driving, it began to wobble at other speeds. Most recently, the speedometer has ceased to function at all. Since I am not familiar at all with exactly how the angle drive system works, I want to make sure I have things straight in my head before I rush off to buy new parts.

Some steps I have taken to try and diagnose the issue:
I have disconnected the speedometer cable coming from the firewall to the angle drive and spun the cable with a drill. The speedometer works. Problem must be the angle drive / dust cap.

Here are some pictures of the dust cap and driver's side wheel (sans wheel) area.
837483738372

After reading a few threads, this is what I've come to surmise: the cable inside the angle drive going to the dust cap has snapped, which means I must acquire a new angle drive. Is this correct?

Also, I've seen in several places to put electrical tape around the dust cap to prevent it from spinning. This is confusing -- under normal operating circumstances, should the dust cap spin with the wheel?

[DMC5180]

Correct. You have a dead angle drive. If you want to save yourself a little grief, order it with the NUT on it. I know the trick to changing it, but it's a little difficult to explain. Maybe some day I'll do 30 sec how to Video.

The tape thing is to wrap a 2-3 times around the O.D that fits into the HUB I.D. I've seen it done but never needed to do it on my car. Technically the dust cap is pinched between the wheel and hub. so it shouldn't need it. If it gets to the point that the Dustcap does spin, your angle drive is about to die anyway. (friction build up)

[jawn101]

Not trying to hijack this thread, but I am having a similar problem as Kenny_Z. Only difference was the speedometer needle would bounce between 0 and 20-25 mph, and then be steady afterwards. After a few months of regular driving, it began to wobble at other speeds. Most recently, the speedometer has ceased to function at all. Since I am not familiar at all with exactly how the angle drive system works, I want to make sure I have things straight in my head before I rush off to buy new parts.

Some steps I have taken to try and diagnose the issue:
I have disconnected the speedometer cable coming from the firewall to the angle drive and spun the cable with a drill. The speedometer works. Problem must be the angle drive / dust cap.

Here are some pictures of the dust cap and driver's side wheel (sans wheel) area.
837483738372

After reading a few threads, this is what I've come to surmise: the cable inside the angle drive going to the dust cap has snapped, which means I must acquire a new angle drive. Is this correct?

Also, I've seen in several places to put electrical tape around the dust cap to prevent it from spinning. This is confusing -- under normal operating circumstances, should the dust cap spin with the wheel?

In that first picture, you definitely have a bit of the shaft sticking out of the dust cap. That would be your problem for sure - the shaft snapped off your angle drive. If it's an OEM angle drive it will need to be replaced. Some vendors sell drives with a replaceable shaft for this very reason (that's what I'm running)

To answer your question, the dust cap should spin with the wheel hub and not independently. Putting a thin wrap of tape around the outer edge so that it stays jammed in the hub is the solution, if the cap spins at a different speed than the wheel hub the speedo will be inaccurate/bouncy. Then when you get up to speed and the spin force (can't remember if it would be considered centrifugal or centripetal in this case) will cause enough friction to keep the cap spinning at the right rate, the speedo evens out.

So, at the very least it looks like a new cap and angle drive are in your future..

[DMC5180]

I have a bit of an issue with the so-called replacement shaft setups. The shaft/cable breaks because the angle drive gears are wearing out and locking up. In other words, Simply putting another cable member in does not fix the reason it failed in the first place. The AD needs to be rebuilt regardless if it is a rebuildable version.

[jawn101]

Very fair assessment. The replaceable shaft isn't the reason I bought this drive, it was rather the price, *advertised* lack of need to lubricate (and subsequent lack of a mechanism to do so), and the fact that I had read the OEM shafts were just a bit too short, whereas this one was a more usable length. Was just trying to be complete for the OP on replacement options :)

Dennis is right though, definitely save yourself some trouble and buy a drive with the nut preinstalled. That turns what could have been a frustrating and long job with lots of fiddly little work into a half hour with a massive wrench. You'll need a 1-1/4" open wrench that you'll probably never use again.

[DMC5180]

You'll need a 1-1/4" open wrench that you'll probably never use again.

Umm, remember why you need it in the first place. :biggrin:

Never say never when it comes to the AD. FWIW: It Helps if you loosen the Hub nut (1-1/4 socket) first (1-turn) before trying to Loosen the AD nut.

[orbitron3000]

Correct. You have a dead angle drive. If you want to save yourself a little grief, order it with the NUT on it. I know the trick to changing it, but it's a little difficult to explain. Maybe some day I'll do 30 sec how to Video.

The tape thing is to wrap a 2-3 times around the O.D that fits into the HUB I.D. I've seen it done but never needed to do it on my car. Technically the dust cap is pinched between the wheel and hub. so it shouldn't need it. If it gets to the point that the Dustcap does spin, your angle drive is about to die anyway. (friction build up)


In that first picture, you definitely have a bit of the shaft sticking out of the dust cap. That would be your problem for sure - the shaft snapped off your angle drive. If it's an OEM angle drive it will need to be replaced. Some vendors sell drives with a replaceable shaft for this very reason (that's what I'm running)

To answer your question, the dust cap should spin with the wheel hub and not independently. Putting a thin wrap of tape around the outer edge so that it stays jammed in the hub is the solution, if the cap spins at a different speed than the wheel hub the speedo will be inaccurate/bouncy. Then when you get up to speed and the spin force (can't remember if it would be considered centrifugal or centripetal in this case) will cause enough friction to keep the cap spinning at the right rate, the speedo evens out.

So, at the very least it looks like a new cap and angle drive are in your future..


I have a bit of an issue with the so-called replacement shaft setups. The shaft/cable breaks because the angle drive gears are wearing out and locking up. In other words, Simply putting another cable member in does not fix the reason it failed in the first place. The AD needs to be rebuilt regardless if it is a rebuildable version.


Very fair assessment. The replaceable shaft isn't the reason I bought this drive, it was rather the price, *advertised* lack of need to lubricate (and subsequent lack of a mechanism to do so), and the fact that I had read the OEM shafts were just a bit too short, whereas this one was a more usable length. Was just trying to be complete for the OP on replacement options :)

Dennis is right though, definitely save yourself some trouble and buy a drive with the nut preinstalled. That turns what could have been a frustrating and long job with lots of fiddly little work into a half hour with a massive wrench. You'll need a 1-1/4" open wrench that you'll probably never use again.


Umm, remember why you need it in the first place. :biggrin:

Never say never when it comes to the AD. FWIW: It Helps if you loosen the Hub nut (1-1/4 socket) first (1-turn) before trying to Loosen the AD nut.

Thanks both for the wealth of information! Learning more everyday :reading:

I've heard good things about Hervey's AD. I think it was stevedmc who mentioned somewhere that he runs the dustcap from DMCH, and Hervey's long speedometer cable and AD and is very happy with this setup. I'm thinking this is that path is the one I want to go down as well. Does Hervey's AD come with the preinstalled nut as you suggest?

[jawn101]

Thanks both for the wealth of information! Learning more everyday :reading:

I've heard good things about Hervey's AD. I think it was stevedmc who mentioned somewhere that he runs the dustcap from DMCH, and Hervey's long speedometer cable and AD and is very happy with this setup. I'm thinking this is that path is the one I want to go down as well. Does Hervey's AD come with the preinstalled nut as you suggest?

Yup, Hervey's is the AD I run as well and comes with a preinstalled nut at a $17 premium. I already listed my reasons why I picked his above, but so far I'm pleased with it. I don't believe there are any dust cap options, only the original one.

[Kenny_Z]

It appears that my problem is that the dustcap was spinning. It does have a decent amount of wear and it might not be long before it starts spinning the square shaft inside the cap. Looks like I'll be ordering a new one. I think I should also grease the angle drive when I get the new cap. That doesn't look simple.

[jawn101]

It appears that my problem is that the dustcap was spinning. It does have a decent amount of wear and it might not be long before it starts spinning the square shaft inside the cap. Looks like I'll be ordering a new one. I think I should also grease the angle drive when I get the new cap. That doesn't look simple.

Good place to start for sure, cheap and easy. But as Dennis said, if the cap was spinning it is likely indicative of pre-existing or any-minute-now damage to other components in the system. If the angle drive shaft was hard enough to turn that it rounded out that cap (made of some kind of amazing super plastic) then you probably will not find that a simple cap replacement fixes the issue.

[DMC5180]

Kenny,

The dust cap itself is spinning or cable socket has rounded out? that's another common thing to happen as friction builds up in the in AD gears or system as a whole.

[Kenny_Z]

Well...seems I was mistaken. I'm going to order a dustcap for sure but I'm not sure it is just that the cap is rounded out. I'm going to see about hooking that drill up after I track down someone to watch the gauge for me.

[DMC5180]

Your drill will have enough power to break things. Go slow with CCW rotation. Then again if breaks now, it's probably a good thing. FYI: 1000 RPM is about 60 mph at the Speedo. I'm not sure if the AD is 1:1 ratio.

[Kenny_Z]

Couldn't find a helper anywhere but thankfully my 1/2 drill has a max speed of 800rpm. I put it up on blocks and locked it so I could look. The gauge holds steady around 50mph. I also did this test with my cell taking video as I varied the speed. It seems that cap is definitely my problem. Looking at it closely I could see where it was rounded out. I think I killed it permanently when I took it out and cleaned it up.

[Kenny_Z]

I think something is binding in the angle drive. I put on a new dustcap. I could turn the angle drive by hand and using a drill didn't seem to break anything. I didn't remove it to inspect anything because I didn't have a wrench large enough. Well, I was almost to work today, the new dustcap was doing well and squeaking I was hearing before was gone. I thought I had the problem fixed. Suddenly the needle starts swinging from 85 to 0 rapidly. It did this for about a minute and then dropped to zero for the rest of the drive. I bet screwed up a brand new dustcap and probably have something binding in the system when it heats up. I'm just going to bit the bullet and order a new angle drive and probably a long drive cable while I'm at it.

[stevedmc]

Get your angle drive from Hervey and before installing it compare it to your old angle drive.

The shaft on my angle drive from Hervey is longer than the shaft on my old DMCH unit. I am curious if all of the Hervey units are longer than the DMCH units.

[DMC5180]

Like I said, The old dust rounded out because the AD gears were wearing out (snagging occasionally). Once you put a fresh dust cap in the binding could no longer release its energy in rounded out cap. The Short drive cable in the spindle has now failed. This is the Classic demise of the Angle Drive. I'm guessing your Dust Cap will be fine.

[jawn101]

Get your angle drive from Hervey and before installing it compare it to your old angle drive.

The shaft on my angle drive from Hervey is longer than the shaft on my old DMCH unit. I am curious if all of the Hervey units are longer than the DMCH units.

When I asked him about it, he said he makes them longer on purpose so they bite into the cap better.

Kenny, sorry to hear you're having to do the whole system. I bet the cap is still ok after only one drive though. Let us know how you do!

[Jonathan]

...and/or you have tightened the lambda box(where the two cables meet) too tight. The cable couplings need to be finger tight only, any tighter and it will bind up.

Hmmm, this is interesting. Is this common knowledge? I have had similar bouncing speedos to dead speedos in the past 2 years and I will admit my connections were tightened with channel locks. I have the replacment kit including angle drive, nut, dust cap and lower cable, but haven't installed them yet. If this finger tight advice is universally accepted, it might have been my problem all along.

[Kenny_Z]

I was going to remove the dustcap here at work but I left my jack sitting in my garage at home. I have the old D's jack but I haven't really inspected that thing since I usually carry my hydraulic. I'll spend another 15 bucks instead of risking that old one collapsing. I'll compare my old angle drive to Hervey's when I do the install.

I'll also check those cables later today. I have never removed them but there's no telling what one of the previous owners did.

[Kenny_Z]

Today I pulled my angle drive. I was spinning it by hand and suddenly it snagged tight and I couldn't spin it anymore. Seems something is broken inside. I've got a replacement from Hervey on the way already.

http://uploads.m-cgi.com/kennyz/Delorean/Projects/speed02.jpg
http://uploads.m-cgi.com/kennyz/Delorean/Projects/speed03.jpg
http://uploads.m-cgi.com/kennyz/Delorean/Projects/speed04.jpg
http://uploads.m-cgi.com/kennyz/Delorean/Projects/speed05.jpg

I'm replacing that steering rack boot and pulled the tie rod end for inspection. I don't like it's condition. I'm ordering a set to replace them while I've got Red off the road. This was probably a good thing as I overlooked a lot while I was focusing on just the speedometer.

[Kenny_Z]

And I just remembered what I wanted to ask. Anyone know what the torque spec for the hub nut? I haven't found it in my manual but I'll keep looking.

[Farrar]

And I just remembered what I wanted to ask. Anyone know what the torque spec for the hub nut? I haven't found it in my manual but I'll keep looking.

I found this reproduction technical service bulletin (http://dmcnews.com/bulletins/ST-09-7.81.html) with some torque specifications, evidently a supplement to the Workshop Manual. There's a bunch of torque numbers for the front suspension on Page 2. Good luck! :)

(P.S. Anyone notice that going to dmcnews.com takes you to some "Webring" now unless you have your browser set to disallow redirects? I find this annoying.)

[sean]

I found this reproduction technical service bulletin (http://dmcnews.com/bulletins/ST-09-7.81.html) with some torque specifications, evidently a supplement to the Workshop Manual. There's a bunch of torque numbers for the front suspension on Page 2. Good luck! :)

(P.S. Anyone notice that going to dmcnews.com takes you to some "Webring" now unless you have your browser set to disallow redirects? I find this annoying.)

I noticed it will do it once in a while but not all the time for me.

[Kenny_Z]

Awesome, looks like this is what I need:

Hub bearing to stub
shaft M22 x 32 190 NM 145 LBs

Bookmarked and I'll be printing out one for my manuals.

Thank you for the info.

[Farrar]

Glad I could help! :)

[DeLorean03]

Hey Kenny!

Not to send you on a wild goose chase, but my car had the exact same identical problem - speedometer bouncing everywhere and then "death". Turned out the lower speedometer cable was so old that the metal wire started to unravel; it had unwound and then "bunched up" on itself. To be safe, I ordered John's "eliminate the lambda counter" cable - it is one less thing you have to worry about. If you've locked in on the problem, then disregard this post. If it comes back though, well, now you got my experience =p.

FYI - I replaced EVERYTHING in the end - the "eliminate" cable, the dust cap, and the angle drive. No issues since (:

[AdmiralSenn]

This JUST happened to me. Unfortunately I don't have all the tools to fix it right now.

[Kenny_Z]

The lower cable feels and looks fine but I'm replacing it with the longer cable from Hervey anyway. I'll stick the other parts in a sealed bag on a shelf.

I guess it is the season for dead angle drives.

[stevedmc]

I guess it is the season for dead angle drives.

Angle drives are always broke, except for mine once I installed one of Hervey's units.

I honestly believe many people just give up and learn to drive around without a working speedometer.

[Michael]

I honestly believe many people just give up and learn to drive around without a working speedometer.

Close, A lot of people don't bother to maintain them correctly. They don't use the right grease(if any at all). Mine has been in place since 2009, has about 15k on it, and works just fine.




Angle drives are always broke, except for mine once I installed one of Hervey's units.

I think you are falling victim to the "empty can" logic. Nobody makes a post to say "Hey, my angle drive is fine...that is all". You only hear from the people who have problems. Also, there no doubt are some that break pre-maturely due to improper installation.

[Farrar]

Hey, my angle drive is fine... that is all. :)

[stevedmc]

Nobody makes a post to say "Hey, my angle drive is fine...that is all".

I do.


Also, there no doubt are some that break pre-maturely due to improper installation.



My last DMCH unit didn't fail due to improper installation. The shaft was too short to go into the dust cap. If the dust cap can't connect to the shaft, it won't turn, plain and simple.

The angle drive I received from Hervey had a noticbly longer shaft and it was able to get a snug connection in the dust cap. His works.

[Kenny_Z]

I think my first one died because I hit a pothole very hard. The next day was when things went south.