TWINRAY

I replaced the t/a bushings and put in new shims. At the time of replacement, I didn’t have a dial caliper and “matched up” the size of the new shims to the old. I now have a dial caliper and pulled out the shims – they measure as follows:

Left side: outside = .360
Left side inside = .301

Right side outside = .487
Right side inside = .237

I would like to “start from scratch” and even out the shims (outside = outside and inside = inside) like they probably should be. I figure previous alignments weren’t done correctly even though the toe is correct and instead of doing each side evenly, shims were put in only one side to get the correct toe. With the shims set as above, I am getting 1/8” toe and I’d like to get that with evenly placed shims.

Now I’ve read the assembly manual procedure where they say to shim completely the gap nearest vehicle center line, between end of control arm assembly bushing and inside wall of frame side rail (and not to use undue force). Then to shim the outboard gap, using force as necessary to obtain solid stack between inner solid stack between inner wall of frame side rail.

What I was thinking of doing is to put (approximately) .270 on the inboard shims (half of the .301 and .237) and whatever evenly I need to fill in the outboard sides – then take a toe measurement, and do evenly whatever I need to get a correct measurement.

Nowhere have I found the oem assembly amount of shims realizing it would vary somewhat on individual cars. Anyone do any research on this? Thanks, Fred

70BBvert

There really is no start from scratch by centering the arms in the pocket. You can string the car and set the toe close by measuring the toe in at the front & rear and get the settings close. Rear camber can be set pretty close at the rear using a carpenters level. For the front you need a caster/camber gauge.

You can make your own skid plates with two vinyl tiles and a dab of grease between them.

I set the car as close as I could & drove straight to the alignment shop While it drove straight, it was off a lot

Jim

TWINRAY

Thanks Jim, I set the camber with a level - no sweat. Seeing how local shops do alignments over the years, I have more confidence in me doing it myself . Regards, Fred

ps. let me send you a PM

Mike Ward

There's no reason to expect that the above would be the result. The frames were not true and square when new, they certainly aren't now.

birdsmith

Fred, in order to properly set the rear toe on one of these cars it must be equal about the longitudinal centerline of the car. merely equalizing it in each frame pocket is no guarantee of that.

A few days ago Skip Burney started a thread titled "rear camber" in the C3 general section where a couple enterprising gentlemen explained their procedure for properly garage-setting rear toe on a C3...very good stuff. Like you, I have an inherent mistrust of most so-called alignment shops. The one time that I did get a decent result was when I paid Sears to do my Vette and (whether the guy liked it or not) I stood there and watched him do my car. I had an $80 4-wheel alignment coupon, at their labor rate I figure they lost money on that job. I had just finished rebuilding the rearend, bushings, bearings, everything, and shimmed it back exactly as it was before I took it apart and fortunately the toe was in spec so no need for adjustment there.

Hope this helps...the info you are seeking should be in the other thread

TWINRAY

Thanks - I will look for that thread and tell all how I made out

Easy Mike

Inner stack sets the toe. Outer stack only packs empty space. My advice would be to use the inner measurements you documented. Those should be good to get you to the alignment shop.

gcusmano74

You can get a rough idea of the "thrust angle" (the net toe of the rear wheels) by sighting from the back of the car, exactly along the outside of the tire at axle height, and looking forward. Set the steering wheel to straight ahead first. You should just barely be able to see outside edges of the front tires. It should look equal from left to right. That'll get you to the alignment shop.

TWINRAY

Thanks for the replies.

I packed the inside shims with 2 – 1/8” shims (that measured .120 each) and 1 – 1/16” him (that measured .060). A measured total of .30” each on each inside.

I levered the trailing arm against the shims and packed the outside shims with 2 – 1/8” shims and 3 1/16” shims to fill it up. For a measured total of .424 on each outside space.

The inside shim measurement was fairly close to the .269 average measurement of my original set-up and I figure would provide a good starting point. To obtain the desired 1/8” toe, I would evenly take out or add shims from each side and then switch them to the other side.

I still had 4 unused 1/32” shims and 4 unused 1/64” shims from the Stainless Steel shim kit for “fine tuning.” One 1/32” (.031) shim measured .039, the others were correct except for one that measured .032. The 1/64” (.016) inch shims measured at .020 and (3) at .019. For my purposes, those measurement differences would be pretty much splitting hairs.

I drove the car a bit to settle the suspension, get home and measured ¼” toe. I then check the camber and the right side is too much positive – I adjust it to the first line “split bubble” negative (military talk – lol) which is about 1/8” (same as the left side). Another ride, another measurement – 3/16” which I could probably call 5/32”. That is close enough considering my measuring techniques to 1/8” for me to leave alone (for now anyway) – car tracks straight and feels good.

Mike Ward

You shouldn't have any left over shims unless the frames pocket(s) are partially collapsed.

TWINRAY

In the S/S shim kit, there are way more shims than you need - because of all the various sizes included.

Mike Ward

No, that's a misconception. The total thickness of all shims, plus the design width of the installed bushing= the width of the frame pocket.

The movement of shims from one side of the arm to the other is what sets toe-in but the total thickness always remains the same.

my 76 ray

Sorry Mike, but I'm going to agree with TWINRAY. There were way more shims in the stainless kit than needed and way more than were originally in the frame pockets.

leadfoot4

I bought a set of the stainless shims a number of years ago, and it provided quite a few shims of varying thickness, to help you get as accurate a toe setting as possible. We (my alignment man and I) had the shims packed in a tightly as possible, and had 6-8 shims left over....

Mike Ward

OK, then I guess the aftermarket kits add more shims that then OEM equivalents. Seems like a waste.

billcarson

you need to set the tracking.what i did was center the steering wheel,set up the front alignment specs and then set the tracking to the rear wheels.i used the fish line jack stand method and squared it for all my measurements.this way the front and rear wheels will track together.takes a few trial and error adjustments before you get it right.good luck.

CplPost

Just how tight do you have to pack all of the shims in there? I just completed the TA replacements on the wife's 78 and was trying to pack them with the thickness of those removed - which some "Bubba" had obviously really screwed up. I finally decided to go with the thickness that "tapped" into place, then secured them with metal tie wraps. The long cotter pins were about 3/4" too short to be useful.

Do I still need to add more and actually beat them into place, in order to be correct?

gcusmano74

No. If you tap them gently into place when the through bolt is loose, it should be fine. Torque up the pivot bolt, and that holds everything in place firmly.

CplPost

THANKS! That is what made sense to me, but needed someone to confirm it for my peace of mind!

70BBvert

If you replaced the trailing arms & put the shims back in the configuration from the old trailing arms your alignment will not be correct. First stop should be at an alignment shop

Jim