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Hi everyone,
I am rebuilding my trailing arms in my 1972 base corvette, which includes new trailing arm bushings.
When I took out the trailing arm the bolt came out relatively easily, so maybe its been replaced before.
I took out my old shims and marked them, but with a new replacement bushing, I have to assume it doesn't have the exact same width as the old worn one; it probably compressed over time...the previous owner got the car realigned, maybe added a shim?
I plan to put the same thickness shims as what I removed, but should I expect to be adding/or taking any out?
Should the bushing have some "preload" to it?
Should I expect to use a hammer installing the shims?
Is there any kind of test for trailing arm drag to ensure the bushing has enough shims?
My advice would be to get it close (like you have) and take it to a good alignment shop - one that understands working on older cars. Take some shims with you, the alignment guy will thank you for that. A good shop will give you a readout of the before and after. Then you don't have to guess. Best, Paul
hopper12
just did this..
should be same total.. there is metal inside the bushing, even bushing gone will still be same shim width in total if rubber oem style
put back how they came out and align..
Assume oem rubber? and you are using tool to compress and swage the end..?
see below
don't drive in with hammer.
check the pocket for squareness, shims should
be tight so the sides of the pocket isn't deformed
when tightening.
align goes without saying
It may be too late, but carefully measure the distance between the inner edge of the TA and the inner edge of the TA frame pocket. When you replace the TA, shim it on the inside tightly (finger tight, not hammer tight) to replicate this exact dimension. Then fill the other (outer) side with the shims required to tightly capture the TA and tighten the bolt to spec. This will get you very close and make it easy for the shop to then align the rear.
On my post rebuild replacement I found I needed less total shim thickness. I know that on one alignment a couple decades earlier they had to reshim. I suspect they may have added some to the existing original shims that may have worn and certainly had rusted. So, perhaps in my case that explained the reduction when I put in new SS shims.
Research the range of alignment of the rear trailing arms. You will probably find that the range is larger than you think. One setting for track, one for sport driving, one for daily driving, ETC.
hopper12
just did this..
should be same total.. there is metal inside the bushing, even bushing gone will still be same shim width in total if rubber oem style
put back how they came out and align..
Assume oem rubber? and you are using tool to compress and swage the end..?
see below
Ah, this makes a lot of sense. I'm using the OEM rubber style.
Looking back on it, I should have measured the original bushing width before I removed it from the trailing arm to see how it compares to the replacement.
Ah, this makes a lot of sense. I'm using the OEM rubber style.
Looking back on it, I should have measured the original bushing width before I removed it from the trailing arm to see how it compares to the replacement.
I agree with taking your Corvette to an Experienced Alignment tech and have them start the alignment by centering the pumpkin (differential). Mine was off to one side a bit and after the alignment the car felt wonderful and it drove so much better.
Be sure to have a couple packs of the Stainless Shims to make the job easier.
I waited until I had both trailing arms rebuilt and several aftermarket suspension components installed and then had the guys at NTB do a 4 wheel alignment for $99. It took hours to do but the results were amazing.
Be sure to tip the alignment Tech before leaving, IF they do the whole job properly.
I agree with taking your Corvette to an Experienced Alignment tech and have them start the alignment by centering the pumpkin (differential). Mine was off to one side a bit and after the alignment the car felt wonderful and it drove so much better.
Be sure to have a couple packs of the Stainless Shims to make the job easier.
I waited until I had both trailing arms rebuilt and several aftermarket suspension components installed and then had the guys at NTB do a 4 wheel alignment for $99. It took hours to do but the results were amazing.
Be sure to tip the alignment Tech before leaving, IF they do the whole job properly.
Can you elaborate on your "centering the differential" comment?
What adjustment is there in the differential?
This is a part of a larger project that had the differential rebuilt, half shafts, pretty much the entire rear suspension of the car.
I just put the differential back into the car, and you just bolt it back to the cross member and back onto the frame.
Any chance you could take some pics of what you are talking about?
Did you end up making your bushing installation tool?
If you did, what did you do to make the big stake that flares the cylinder?
I debating whether I want to buy 1 for $100 and wait 7 days, or make one for $15. The professional tools have that cut out to center the bushing, but I'm not sure that's really necessary for someone who does this 2 times.
Last edited by mongoose87; Jan 7, 2022 at 04:43 PM.
Did you end up making your bushing installation tool?
If you did, what did you do to make the big stake that flares the cylinder?
I debating whether I want to buy 1 for $100 and wait 7 days, or make one for $15. The professional tools have that cut out to center the bushing, but I'm not sure that's really necessary for someone who does this 2 times.
Well, I got my trailing arms rebuilt, with new bearings and bushings.
Repainted all the stuff with a rattle can to make it look good for at like a week. ha
I put the same amount of shims in that I took out, but it was tough to get them all back in. I had to use a hammer to get them all in. Actually, on the driver's side, I had to remove one of the thinnest shims because I couldn't get it in, even with a hammer.
I'm actually kind of surprised how much I can flex the bushing in and out even with the shims put in. I put the rubber bushings in, but now I wonder how much stiffer the poly ones are. I know they aren't recommended though.
I HAVE ANOTHER QUESTION AFTER DOING ALL THIS I hoping all you kind folks can help me with.
Now I am connecting the half shafts to the trailing arms, I am finding that the passenger side went together no problem, but the driver's side has pretty big gap between the spindle on the trailing arm and the half shaft up joint.
I need to really flex the trailing arm inward, toward the differential to get the half shaft u joint close enough to the trailing arm spindle.
Again, used the same amount of shims on each side as what came out with the hope that it would be somewhat aligned.
Is this force inward somewhat normal/expected?
I should have just started to install the strut rod and brought them together with that, but I was an idiot and used zip ties to hold the arm pushed inward so I could screw in the bolts.
Seems like a lot of unnecessary force on that half shaft and u joints.
Does this indicate that my alignment will be way off after replacing the the trailing arm bushings?
When I installed refurbished strut rods they didn't line up. I figured out it's because the trailing arm were hanging down. Nothing lines up with them hanging.
Those wood blocks do not help..try a jack on rollers to bring arm in closer and enough in air to simulate close to ride position..should be easy without strut or spring on..
More shims after new trailing arm bushing
