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I have been unable to get the rear suspension toe adjustment on my 68 convert to the proper setting. It was in a 1/2 inch total toe out condition when I got the car. I recently replaced all of the bushings on the rear suspension and got the old style trailing arm shims out and replaced with the new style open ended stainless steel ones. Even with all of the shims on the outboard side on both the driver side and passenger side the toe is 3/8 inch total toe out. I am wondering if the PO hit something hard, like a curb or speed bump and bent the trailing arm. Is there a way to check the straightness of the TA? I don't want to just blindly replace the TA before knowing if that is the problem.
Most likely the trailing arm(s), unless it has incorrect (too short) half shafts or something very odd like that. Or chassis possibly, but I think that would be obvious, if it were somehow stretched between the trailing arm mounts!
Looks like I will be taking the TA off to check if it is bent. I thought there was a bend about 8 inches from the bushing (see arrow), but from the photo posted in your link, it appears that is supposed to be there. I will have to check if the flat area where the four studs fasten the bearing housing has been bent. The PO put 20 inch rims on the back, so I don't know what he may have done to make them fit.
Check the 1/2 shaft length. Should be 13 7/8" u-joint center to center. 80/81 used shorter shafts, 13 1/2" center to center and look the same as the long ones. 3" diameter.
The bushings look like poly. As long as you are going to pull the arm out, do yourself a favor and replace the bushings with rubber. I have replaced broken poly on my two cars and helped two friends replace their crumbling poly bushings as well. Jerry
The bushings, just replaced three weeks ago, are polyurethane and are noticeably wider. However, the ones I removed were rubber and still could not be brought into a toe in setting, even with all shims on the outboard side. I just checked the length of the half shaft on the driver side. It is difficult to get an accurate measurement with it on the car, but it looks like it is short and not the correct 13 7/8 inch length center-to-center on the u joint ends. So it may be from a 1981 or later car. This makes some sense, since when I ordered the bushings for the stock strut rods for a 1968 car, Eckler's sent the correct ones. They did not fit- way too small diameter. I exchanged them for bushings for a 81 and later car and they fit. So Bubba must have had a later year parts car that he used to swap out parts for the 68 car. I'm going to crawl under the car and get an accurate length for the half shaft, but it looks like that might be the problem. Good ole bubba.
I have been unable to get the rear suspension toe adjustment on my 68 convert to the proper setting. It was in a 1/2 inch total toe out condition when I got the car. I recently replaced all of the bushings on the rear suspension and got the old style trailing arm shims out and replaced with the new style open ended stainless steel ones. Even with all of the shims on the outboard side on both the driver side and passenger side the toe is 3/8 inch total toe out. I am wondering if the PO hit something hard, like a curb or speed bump and bent the trailing arm. Is there a way to check the straightness of the TA? I don't want to just blindly replace the TA before knowing if that is the problem.
How are you measuring the toe alignment ?.
Compared to my 78 most of the shims are in the inner side of the trialing arm vs yours where all are on the outer side. This would only make sense if the wheel hub is in the wrong position or the bushing in not centered in the trailing arm.
Last edited by cagotzmann; 03-20-2019 at 09:28 PM.
The bushings look like poly. As long as you are going to pull the arm out, do yourself a favor and replace the bushings with rubber. I have replaced broken poly on my two cars and helped two friends replace their crumbling poly bushings as well. Jerry
Poly is not the best bushing for the front of the trailing arm. That bushing has to not only rotate but it also twists with suspension movement. I'm sure some poly bushings are better than others but my felling is they are not meant for a twisting motion. JMO
Compared to my 78 most of the shims are in the inner side of the trialing arm vs yours where all are on the outer side. This would only make sense if the wheel hub is in the wrong position or the bushing in not centered in the trailing arm.
I am measuring using two systems. I use my QuickTricks to get a rough measurement and follow up with a Hunter system at Warrenton Tire and Auto. The alignment on your 78 is unique to your car, based on wear, damage and how the car came off the assembly line. Mine is way off and so far the cause is not identified.
I got an accurate measurement and the half shaft is 13 7/8 inch. I checked with Eckler's and they confirmed that is the correct length for the 1968 half shafts. So.... I still do not have an answer why the toe is so far off. DUB mentioned in one of his posts that the flat mounting surface where the bearing housing is attached with the four studs may be bent. I guess when I have time I will pull off the TA on the driver side, which is the worst, and see what it looks like. I had it off the car to replace the bushing and had the bearing housing sent to VanSteel for rebuilding but was not looking at it for bends. If it was bent, it was not apparent.
"If those are poly, then it's not the right ones for a vette" They are the ones supplied by Eckler's part # 25-122880
Mine are Energy Suspension and do not look like that hence my comment. The ES poly bushing is simpler in design and installation than what you have. Also, the ES poly is designed to pivot only once shims are added and the pivot bolt is torqued. The strut rod also stabilizes the bushing. There is very little movent of the ES bushing, if any. I hope you get your setup sorted out.
Here are the ES poly for comparison:
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Just asking, But, after you change a setting , did you put it on the ground. Roll it at least 5 feet back, then forward (or vice versa) to get the suspension and rubber to settle?
Just asking, But, after you change a setting , did you put it on the ground. Roll it at least 5 feet back, then forward (or vice versa) to get the suspension and rubber to settle?
Yes I do that when I check it at home and assume they do the same at the alignment shop I go to.
Just asking, But, after you change a setting , did you put it on the ground. Roll it at least 5 feet back, then forward (or vice versa) to get the suspension and rubber to settle?
Originally Posted by lionelhutz
What did the thrust angle measure on the alignment rack? If that was off to one side it could be indicating which arm is possibly bent.
The driver side has always been off the most. When I got the car the half shaft was pulled out of the diff about 1/2 inch, due to the snap ring being off the splined end of the shaft inside the diff. I fixed that, but it is still off. Attached is the print out before replacing the snap ring I can't find the most recent print out, but it was still not toed in like it is supposed to be.
03-19-2019, 12:09 AM
Trailing arm toe adjustment problem
