I am redoing my rear wheel bearings so I took the time to take the rear end out and look inside. In checking the side yoke spindles I have 0.027 and 0.032 inch clearance between the spindle and center pin. Looking thru past posts on this topic it seems 0.010 to 0.020 inch clearance is desired. Other than the clearance issue the rear end looks fine. No chips or wear on the spindle snap ring grooves. Should I be concerned with these clearances. I only put 2 to 3 thousand miles a year on the car and do not bring it to the track.

 

You'll be ok with those, but as long as you have it out putting in rebuilt hardened ones wouldn't hurt.
My son just removed his 75 differential and it has over .200 so we're going to rebuild the whole thing. We're also going through the rear Tarms/bearings.
Good luck,
Gary

 

Factory specs allow up to .080 (!), but handling would be awful with that much. yours are fine for just cruising, but tighter is better if you want precision.

Hans

 

I just installed new side yokes in mine. They would have been approximately .032" if I just installed them with the c clips. I used 1.2"i.d (1.45" o.d.) steel shims from Ratech Manufacturing behind the C clip to bring the clearance to .001". As both the clutch discs wear and the yoke end, the clearances will again grow, but for now they are perfect.

Dan of Van Steel was great in e mailing me back regarding this. He was very generous with his offer of helping. The Forum really has some great folks on it. He agreed that the side yokes should be set up tight, but didn't think as much about my idea of the shims behind the c clip. But for me it is much easier to get to and to change later than opening up the clutch pack and putting shims there.

For what it is worth, my original side yokes with over 100,000 miles had very little wear. I only continued with the new yokes because they have the heavier duty bolted cap arrangement for the half shafts instead of the U bolts. Dave Herlinger, a fabulous local Vette mechanic in Mountain View, CA, http://www.caspeed.com/dhfaq.html says that between 78 and 81 the supplier to Chevrolet did not build them to specs and they wore out very quickly. They need to be heat treated on the ends to give them adequate surface hardness. This is a fairly simple job that uses an acetylene torch to heat the end quickly until it glows, then quench the end in water. If the whole part were treated that way, it would become too brittle. This is why acetylene is so good because it heats just the area you want fast. A propane torch would not be as good.

Glass has a tremendous surface hardness, but is brittle. A perfect piece would have the surface hardness of glass with the strength of steel beneath.

Chuck