Trailing arm shimming

[Martyn T.]

Is it possible to get away with reinstalling the same thickness shims as were removed from trailing arms, when the original arms are rebuilt ( by Bairs) ? and getting a good rear toe in ? I would like to put in the original style , but they say alignment is difficult vs. using slotted. Or , is a rear toe in adjustment inevitable after removing the trailing arms ? Actually, the original shims I removed could probably be used again.
Thanks,
Marty

[Stephen L.]

Re: Trailing arm shimming

You might get lucky using the same thickness shims. Its worth the effort to reinstall the same thickness and then get it aligned to see if it all worked out.
I tried to get away with that and I was close... but not close enough. Had to move the shims around for correct alignment. I reused my original trailing arms with new bushings. I bought new non-slotted shims.
Make sure you go to an experienced alignment shop who knows how these things are aligned before you start.

[Russ S.]

Re: Trailing arm shimming

You should be very close if not in the exact location as you were providing you are sure you got back your own trailing arms.

[Martyn T.]

Re: Trailing arm shimming

How much can you be off from I believe 1/8" toe in before it noticable driving and or tire wear ?

[Rob M.]

Re: Trailing arm shimming

Is it possible to get away with reinstalling the same thickness shims as were removed from trailing arms, when the original arms are rebuilt ( by Bairs) ? and getting a good rear toe in ? I would like to put in the original style , but they say alignment is difficult vs. using slotted. Or , is a rear toe in adjustment inevitable after removing the trailing arms ? Actually, the original shims I removed could probably be used again.
Thanks,
Marty

Marty,

You could be lucky and it works out perfect - who knows. When I did this project I installed the same number as I removed, but it had to be changed to get the alignment correct. I would strongly suggest that you find a reliable alignment shop to check and install the shims. You might also check the archives as it is full of great advise on the subject.

Good luck

[Joe L.]

Re: Trailing arm shimming

Is it possible to get away with reinstalling the same thickness shims as were removed from trailing arms, when the original arms are rebuilt ( by Bairs) ? and getting a good rear toe in ? I would like to put in the original style , but they say alignment is difficult vs. using slotted. Or , is a rear toe in adjustment inevitable after removing the trailing arms ? Actually, the original shims I removed could probably be used again.
Thanks,
Marty

Marty-----


Using the original shims will get you close enough to get it to an alignment shop with no problems. You might even get lucky and have it dead-on.

However, I would NEVER, EVER use the original style "2 hole" shims. The slotted shims are the way to go. You don't really need to add the cotter pin for these, either. If you tuck them down in the pocket in the frame and tighten the forward bolt properly (ONLY after the car's suspension is normalized), you will have no problem with losing shims.

For me, I like the stainless steel shims. That way, they'll always look new instead of rusty.

[Alan D.]

Re: Trailing arm shimming

Marty, I have done just that with success. Used the original 2 hole shims.

One thing to do before taking apart is measurements which include the back bearing since it will change the overall thickness number. Measure each side of the bearing for shim thickness. You may find that the thickness on each side needs to be adjusted, in my case needed to reduce a little due to larger bearing. Just machined a little off the 1/4 shims.

Like Joe's idea of the stainless (little harder to mill).

Yes the slotted shims will make life a lot simplier however it usually is the last shim that is a pain. So you could take one of the 2 hole shims and make (mill) it into a slotted style (do a 1/4" shim)

Now these 2 hole shims will hang out of the pocket so you still have possibility of it falling out however various methods can be devised to prevent that.

Now after all that effort I would think (do not know) if it cost you a point that would be a lot -- so your decision.

[Jim T.]

Re: Trailing arm shimming

Marty-----


Using the original shims will get you close enough to get it to an alignment shop with no problems. You might even get lucky and have it dead-on.

However, I would NEVER, EVER use the original style "2 hole" shims. The slotted shims are the way to go. You don't really need to add the cotter pin for these, either. If you tuck them down in the pocket in the frame and tighten the forward bolt properly (ONLY after the car's suspension is normalized), you will have no problem with losing shims.

For me, I like the stainless steel shims. That way, they'll always look new instead of rusty.

If the alignment person did not tighten the shim location enough and a person discovered the shims were coming out, what count would you use to verify that no shim has been lost if both sides were discovered to possibly have lost a shim?

[Michael W.]

Re: Trailing arm shimming

Jim,

I don't believe there is a consistent, finite number of shims due to the multiple alignments a car would have had over the years as well as the production tolerances of the frame pocket and trailing arm bushing dimensions.

If the shims are loose in the pocket, there's room for more.

[Timothy B.]

Re: Trailing arm shimming

Jim,

The proper procedure is to set the toe in by installing the inside shims then fill the outboard side with shims so that the last shim taps in lightly. Don't tighten the through bolt until the weight is on the tire. Use never seize so everything slides in easily

The slotted shims are great and they tuck nicely inside the frame pocket.

[Domenic T.]

Re: Trailing arm shimming

When the final shims are in, every thing should be tight as those are the 2 places that move the car forward.

No room for loose there.

DOM

[John H.]

Re: Trailing arm shimming

In the plant, rear toe and camber was set with the frame clamped upside-down in a fixture, with the rear hub located by a pin in the spindle machining center at design ride height. That locating plate on the fixture with the center pin also had four spring-loaded plungers connected to linear transducers that contacted the hub surface at 12, 3, 6, and 9 o'clock that measured hub displacement in both vertical and horizontal planes to determine camber and toe angles.

The inboard side of the bushing at the front of the trailing arm was shimmed to the inboard wall of the frame pocket until the red light on the panel went out and the green light came on, and the resulting gap between the outboard side of the bushing and the wall of the frame pocket was stuff-shimmed to fill it, and the pivot bolt was torqued.

Camber was set in a similar manner; the cam bolt was turned at the inboard end of the strut rod until the red light went out and the green light came on, and the nut was torqued.

The rear spring was compressed with an overhead fixture and connected to the trailing arms via the link bolts after the camber and toe set process was completed.

http://img.villagephotos.com/p/2002-2/13522/RearAlign11024.jpg