My Front Suspension is Badly bent, What do you think?

[vwdmc16]

Its only taken nearly 4 years but I finally got my car on an alignment rack (most places didnt want to touch a DMC, others I wont let touch my DMC) at my new shop. My car has always pulled to the left pretty badly. Now I know exactly why. The rear toe is a bit off, that can be fixed with shims. and the camber is excessive and uneven( remember ive lowered the car about 3"), that can be fixed with adjustable links like DPI sells. But the front has issues. If you havent read my resto thread my car was an east coast rust bucket that probably has never been driven lovingly. So here is the run down of the alignment:

Front toe Spec: .20 to.28' in

Left Front toe actual: .11 Right front toe actual: .07
(Its 3/10') off so its not that bad and its the easiest part and the last to adjust)


Camber spec: -0.5 to 0.0' ( Ideally I prefer to have about -1.2 to -1.5' to help on hard corners)

Left Camber: -1.4' Right camber: .1'

(Positive camber=bad!)


Front Caster spec: 3.5 to 4.0'

Left Caster: 1.1 Right Caster: 6.0'!!!!!!


( This has to be what pulls my car to the side, a difference of 4.9' side to side is really off)









So besides replacing all of my control arms, what are my options? fully adjustable tubular arms?

[DMCMW Dave]

This is a very unusual design where the sway bar is also the thrust arm. Thanks Lotus!

Caster is actually set by the stabilizer bar position, normally not adjustable. If welding repairs were made to the crumple section and not done accurately, the stabilizer bar is not clamped in the correct position. The only fix is to tweak (repair) the front frame section or invent an adjustable stabilizer bar/bar clamp.

This could also be indicative of a very worn inner bushings, worn stabilizer bar bushings, bent lower arm etc.

Camber is not adjustable at all. It is set by the relative length of the upper and lower control arms, so being that far off you probably have a bent spring tower or some really bad bushings.

[vwdmc16]

The crumple tubes have cracked and been repaired and reinforced, all sway bar bushings are pretty new and very tight, the main arm bushings are original but dont have significant visual deformation, Ive boxed the control arms too. Its possible that the arms and crumple tubes were mesded up before and Ive locked them in that position with the reinforcements or possibly ive made it worse myself.


How about I swap control arms left to right, the issue probably wont go away but if the errors move to the opposite side then I know its the arms, if not then its the frame. If this car came into your shop, what actions would you take?

[DMCMW Dave]

If this car came into your shop, what actions would you take?

Depends on the customer's budget and how much they were going to drive it. I suspect after visual inspection and some measurements, I'd end up recommending replacing the crumple section completely. Honestly most people would live with it.

[Bill Robertson's Sock Puppet #1]

This is a very unusual design where the sway bar is also the thrust arm. Thanks Lotus!

Ed Uding's LCA brackets basically render the whole swaybar as backwards thrust arms problem moot. They are the closest thing to plug and play lower wishbones currently available.

Note that there appears to be a weakness mounting Ed's bushings in direct contact with the shock tower: they have a tendency to work themselves out of the brackets as they rotate up & down -- a problem easily remedied by mounting the bushings against *HARDENDED* backing washers (which in turn rotate against the protruding pivot bolt tubes, not against the shock towers themselves). Mounting the bushings against backing washers also eliminates annoying polyurethane squeak. You will need longer pivot bolts than supplied with the kit.

Mike Loasby himself was experimenting with true lower wishbones when the DMC house came crashing down:




Lotus also went to lower wishbones on their later cars.

[vwdmc16]

wow, thats neat, using another upper arm to make a lower A arm. Not a bad idea if you have a bunch of dmc part bins at your disposal. That lower arm looks a bit weak for my trust, should be boxed to make it solid.


I played around with adding a rear radius rod with heim joints similar to the second picture from Wolfgang Hank's site, more important issues arose since then but its still an idea I want to continue. The front frame section even new is not strong enough for heavy loads, I drive my car hard and I will need the suspension to stand up to the loads. Ive debated on removing my crumple tube section in favor of a stronger and simpler tube steel section. That would be able to carry the forces and be able to mount at a better angle than what I mocked up below.

[BABIS]

wow, thats neat, using another upper arm to make a lower A arm. Not a bad idea if you have a bunch of dmc part bins at your disposal. That lower arm looks a bit weak for my trust, should be boxed to make it solid.


I played around with adding a rear radius rod with heim joints similar to the second picture from Wolfgang Hank's site, more important issues arose since then but its still an idea I want to continue. The front frame section even new is not strong enough for heavy loads, I drive my car hard and I will need the suspension to stand up to the loads. Ive debated on removing my crumple tube section in favor of a stronger and simpler tube steel section. That would be able to carry the forces and be able to mount at a better angle than what I mocked up below.

do you know that Deloman removed that system because it can't work at all in this shape?


look at this later style LCA of the lotus esprit :

complete_arm.jpg

in this case, the fulcrum of the bushing hole of the diagonal arm (which does the triangulation) is perfectly in line with the fulcrum of the hole of the LCA itself, and this is the only way it can work properly..

another interesting thing we can see in the lotus arm is that the holes for the antiroll bar are in the middle of the arm and not at the end like in our arms.. (but in our suspension the antiroll bar does even the triangulation)

[andyd]

Here is "work in progress" from the EuroTec forum.

http://deloreaneurotec.com/forum/vie...2ff5b42317c497

Hope you can see it, not sure if you need to be signed in. Looks like a good answer tho,

lower track control arm 1.jpglower track control arm 2.jpg



andy

[David T]

Compensating for a bent or incorrectly repaired frame by making adjustable parts is not a good way to "fix" things. The frame is the foundation of the whole car and it really does need to be accurate and strong. I would take measurements and compare them to the diagram in the Workshop Manual (last section). Then do what is necessary to get the frame right. When you take the car to a shop for an alignment it is more properly called a "Static" alignment. The are only measuring at one position, ie, they do not measure over the range of travel of each wheel. If parts are bent or not where they should be the alignment could deviate wildly over the range of travel of each wheel. That can make the car uncontrollable while actually driving. Consider what can happen if the toe of a front wheel changes drastically during a panic stop. It could cause you to go right off the road before you could stop it! Or hit a car in an adjacent lane. Unless you really know what you are doing when you make changes with alignment you are best served by keeping the car as stock as you can. It is not just about going straight down the road and not wearing tires badly. As for the rear toe you are not supposed to use too many shims. If you can't get it right (with I think 5 max) something is very wrong.
David Teitelbaum

[DMCMW Dave]

I really don't see how this can work as shown. As the suspension goes into compression or rebound, the sway bar and the new thrust arm are trying to move in opposite directions (caster angle change). Look under any other car and you'll see that the sway bar is connected to the control arm with small ball joints aka a stabilizer link, it will not be mounted directly to the arm like this car.

Also - the point on the frame where the thrust arm is connected is not very strong. I would predict that in short order you'd tear the arm off the frame and/or ripple the frame. And rip the bushings off the end of the sway bar.