C2 trailing arm shims

[Ralph P.]

[Richard G.]

Re: C2 trailing arm shims

In 1963 GM manufactured them with slots, you may know this already.
It is my belief that getting as many shims as possible into the area and tightening the retaining bold may retain the shims just fine.
Requires careful work and some due diligence is all.
As an alternative one could slot a set of shims so you could get the settings correct and then remove the slotted shims and replace them with the ones with the holes. It could be a one time shot that way. Don't forget to tighten the swing arm retaining bolt with the weight of the car on the swing arms.
Rick

[Joe L.]

Re: C2 trailing arm shims




Ralph------


Very simple. Use the slotted type shims, install the shim pack tightly (i.e. drive in the last thick shim with a hammer) and tighten the bolt to specification. I used slotted shims without the retaining pins in my 1969 for many years and miles and never lost a shim.

Want more "insurance"? Rotate the shims down into the frame pocket as they are supposed to be.

I NEVER, EVER recommend the use of the "2 hole" shims. I would NEVER, EVER use them. NEVER, EVER.

[Ralph P.]

Re: C2 trailing arm shims

After recently dealing with getting the trailing arms OUT....I agree !

[Leif A.]

Re: C2 trailing arm shims

In 1963 GM manufactured them with slots, you may know this already.
It is my belief that getting as many shims as possible into the area and tightening the retaining bold may retain the shims just fine.
Requires careful work and some due diligence is all.
As an alternative one could slot a set of shims so you could get the settings correct and then remove the slotted shims and replace them with the ones with the holes. It could be a one time shot that way. Don't forget to tighten the swing arm retaining bolt with the weight of the car on the swing arms.
Rick

This is exactly how I did mine. Once done, with normal driving, you won't have to do it again. The correct two hole, factory installed shims will NOT tuck into the frame and they're not supposed to on a C2. I know they changed the design and retention on later C3, but pictured below is the way the shim pack will look when correctly installed.

[Joe L.]

Re: C2 trailing arm shims

This is exactly how I did mine. Once done, with normal driving, you won't have to do it again. The correct two hole, factory installed shims will NOT tuck into the frame and they're not supposed to on a C2. I know they changed the design and retention on later C3, but pictured below is the way the shim pack will look when correctly installed.

Leif------


Yes, the "2 hole" shims were 1/4" longer (4-3/4") than the slotted type (4-1/2"). However, the C2 AIM's show them oriented "downward" just as the C3 AIM's show.

In any event, the "2 hole" shims make rear alignment a nightmare considering the difficulty in removing and re-installing the bolt. Of course, it's possible to do as has been suggested-----do the alignment with slotted shims and then replace them with the "2 hole". Even that represents a lot of extra work and hassle. My car had the slotted shims installed for many years and many miles without them being tucked down into the frame pocket (they are now but were not for most of the car's life). I never had any problem whatsoever with shims falling out.

So, why did I orient them down into the frame pocket now? The shims are "ugly" and "crude-appearing" when oriented higher.

[Ed S.]

Re: C2 trailing arm shims

Ralph------


Very simple. Use the slotted type shims, install the shim pack tightly (i.e. drive in the last thick shim with a hammer) and tighten the bolt to specification. I used slotted shims without the retaining pins in my 1969 for many years and miles and never lost a shim.

Want more "insurance"? Rotate the shims down into the frame pocket as they are supposed to be.

I NEVER, EVER recommend the use of the "2 hole" shims. I would NEVER, EVER use them. NEVER, EVER.

Joe, besides the fact that they are difficult to install is there another reason why you say NEVER, EVER use them? Just curious.

[Joe L.]

Re: C2 trailing arm shims

Joe, besides the fact that they are difficult to install is there another reason why you say NEVER, EVER use them? Just curious.

Ed------


The reason is the difficulty in performing rear alignments. Most shops that will even do 1963-82 Corvette rear alignments (and I'm sure there are fewer and fewer that will do so) will not do it on a flat rate basis. In other words, they will do it only on an hourly basis. Most important, though, is that they are far more likely to do it only until it's "good enough" rather than to a definitive setting. So, one will end up paying a lot of money for a "good enough" job.

Of course, one could do as suggested above and replace the "2 hole" shims with the slotted shims before alignment, then replace them with the "2 hole" shims after alignment. However, the next time one takes it in for alignment one has to re-install the slotted shims before taking it in and re-installing the "2 hole" shims afterwards. To me, this is a huge hassle for a minuscule configuration benefit.

As I say, personally, I would never, ever use the 2 hole shims.

[Donald L.]

[Frank D.]

Re: C2 trailing arm shims

If the shims are installed tightly enough, and tucked into the trailing arm front frame cavity you won't lose them - they didn't come out on my 63 even after the poly bushings (installed by previous owner) crumbled into ground pepper..

[Gary B.]

Re: C2 trailing arm shims

Don,

If the shim pack is to be tightly packed before the bolt is tightened, meaning the last shim must be tapped straight in with a hammer, then I think what you describe won't work for that last shim. Or am I missing something?

Gary

[Ralph P.]

Re: C2 trailing arm shims

Thank you, Don... Your idea is one I had seen , but, didn't remember any details. I assume you've done this ? Looks like a cut would be made on an angle and just wide enough for the cross bolt ? What did you use .. Grinding wheel , hack saw, or ? Seems like if done , you would have a secure shim that matches the original installation exactly ...yet much easier to change on alignment !

[Donald L.]

[Joe L.]

Re: C2 trailing arm shims

Don,

If the shim pack is to be tightly packed before the bolt is tightened, meaning the last shim must be tapped straight in with a hammer, then I think what you describe won't work for that last shim. Or am I missing something?

Gary

Gary----


Correct.

[Gene M.]