C3 Trailing Arm Rebuild
Thread Starter
1st Gear
Joined: Jan 2015
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C3 Trailing Arm Rebuild
When disassembling one of the trailing arms from a 1980 corvette I noticed that the spindle flange nut was only slightly tighter than finger-tight......should have been torqued to 100 ft/lb. Thot that maybe someone had forgotten to torque the nut at the factory since nobody has been into these trailing arms since new. After cleaning the spindle support and driving in the new bearing races I started to set up the new bearings using my bearing set-up tool. I usually start with the thickest shim (.145) and then measure the end play with a dial indicator. When I tightened the spindle flange nut to 100 ft/lb the spindle was way too tight indicating that a thicker shim is required.....but the .145 shim is the thickest recommended shim to use. Was thinking that the spacer could be milled down a few thousands and then stack shims to get the proper. 002-.008 bearing clearance. Has anyone else run into this issue?
Melting Slicks
Joined: Nov 2006
Posts: 3,409
Likes: 1,821
From: Apple Valley, MN
First question - are you 100% sure you have the races fully seated?
Second question - have you checked the spacer for parallelism? Should be no more than 0.0005.
I would add shims as needed to assess just how much you are looking at in terms of total thickness.
Forget the 0.002-0.008 values. Shoot for 0.0015-0.002.
Second question - have you checked the spacer for parallelism? Should be no more than 0.0005.
I would add shims as needed to assess just how much you are looking at in terms of total thickness.
Forget the 0.002-0.008 values. Shoot for 0.0015-0.002.
Race Director
Joined: Nov 2006
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From: Sunshine Coast, Queensland, Australia
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Cruise-In VIII Veteran
My first thought as well. Nothing behind those races? Absolutely certain they are straight and fully seated?
No one has cut down the center spacer?
How can you be totally certain that no one has been in there before you in 45 years? Have you owned the car from new?
No one has cut down the center spacer?
How can you be totally certain that no one has been in there before you in 45 years? Have you owned the car from new?
Tech Contributor
Joined: Aug 1999
Posts: 15,173
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From: Connecticut, USA
Interesting situation.
Some thoughts.
1- what brand were the old bearings, if you checked them. Only NDH were used on C3 Corvettes, earlier cars had Hyatt. NDH - New Departure Hyatt. So any other brand means they were replaced at some point.
2- The bearing supports were slightly different with later C3's but the bearings were all the same, and the machining should be close. So, if the races are the correct one and fully seated that aspect should be fine.
3- You said you usually start with a 045" shim, so you have done this work before, and this is an oddball?
4 - Part of my procedure setting up rear bearings is to check and parallel grind the bell spacer and grind a new shim to size. The original bell spacers do wear and can be a problem. Did you measure the length?
5- How the bearings are setup makes a huge difference. Again, I use my own procedure for this but following the GM manual will get you there as well. YouTube videos leave a lot to be desired.
6- Bottom line, if you assemble them and torque the axle nut to 100+ Ft/lb and it is binding then you don't have enough space between the bearings- which you already know. But is it possible, since you found the nut loose from the start there is a dimension issue with the axle?
Some thoughts.
1- what brand were the old bearings, if you checked them. Only NDH were used on C3 Corvettes, earlier cars had Hyatt. NDH - New Departure Hyatt. So any other brand means they were replaced at some point.
2- The bearing supports were slightly different with later C3's but the bearings were all the same, and the machining should be close. So, if the races are the correct one and fully seated that aspect should be fine.
3- You said you usually start with a 045" shim, so you have done this work before, and this is an oddball?
4 - Part of my procedure setting up rear bearings is to check and parallel grind the bell spacer and grind a new shim to size. The original bell spacers do wear and can be a problem. Did you measure the length?
5- How the bearings are setup makes a huge difference. Again, I use my own procedure for this but following the GM manual will get you there as well. YouTube videos leave a lot to be desired.
6- Bottom line, if you assemble them and torque the axle nut to 100+ Ft/lb and it is binding then you don't have enough space between the bearings- which you already know. But is it possible, since you found the nut loose from the start there is a dimension issue with the axle?
