I need a little advise. The pinion seal in the rear end of my 1975 Vette is leaking pretty good. I need to know how hard the seal is to replace in the car vs. removing the whole unit and doing it on the bench. What do I need in the way of special tools, etc? Thanks for the help!! Darrell
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
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#2-1985 Bright Red/Carmine Cp.L-98/auto
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Unless you're just a glutton for punishment, you would be better off removing the diff for this job. To do it properly, you need to remove the nut on the yoke, then use a puller to pull the yoke off. The real issue, for someone that doesn't do this kinda thing all the time, is getting that nut back on there with the proper torque....not too tight, and not too loose. Too tight, and you stand a good chance of wiping the pinion bearing out within a few miles. Too loose, and you wind up with a noise, the possibility of damaging the gear set, AND a pinion seal that still leaks. I think there are specs for tightening the nut on "used" bearings, but I've always done it by feel. I've also done hundreds of diffs over the years, so....
____________________________________ Joel Adams C3VR Lifetime Member #56 My Link
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I would go for dropping the diff out also..not really all that hard..may want to have the whole thing gone thru also..Bairs does a good job of this..so I have heard..or you could send it to Joel so he could feel your bearings! That's funny..just watch out for the while I am there bug..it likes to bite when you start taking stuff apart..
Rich
____________________________________ My first parade at Carlisle 2010
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Joel;
Any idea where would I find the specs for tightening the rear diff. pinion flage nut on used bearings?
Also, when you've done this by feel, what was your criteria?
____________________________________
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Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
Am-Fm/map light National/Regional/Chapter NCRS "Top Flight"
#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
Joined: 11/8/2003
Posts: 19515
windrider1200 said: Joel;
Any idea where would I find the specs for tightening the rear diff. pinion flage nut on used bearings?
Also, when you've done this by feel, what was your criteria?
Well....when only replacing the seal(or yoke), yer "supposed" to check the pre-load on the bearings before removing the nut. Then, when re-installing the nut, go 1-5 inch pounds tighter than it was. This is the suggested spec from the Service Manual. So, yer supposed to put an inch/pound torque wrench on the nut before dis-assembly, and measure how much torque it takes to turn the yoke(wheels off the ground), NOT loosen the nut. Then tighten the nut so that it takes 1 to 5 inch pounds MORE to turn the yoke than that on re-assembly.
"Criteria"? Hard to explain how I do it. It just has to "feel" right. It has to be tight enough that you cannot feel ANY play in the yoke/bearings, but not so tight that you have to work to turn it by hand. It's just something that I have developed a "feel" for over the years. It's not something that I recommend to everyone to try....it gets expensive if yer wrong...and I have been once or twice, but only on ones that already had bearing damage.
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Too loose, and you wind up with a noise, the possibility of damaging the gear set, AND a pinion seal that still leaks. 
Hard to explain how I do it. It just has to "feel" right. It has to be tight enough that you cannot feel ANY play in the yoke/bearings, but not so tight that you have to work to turn it by hand. It's just something that I have developed a "feel" for over the years. It's not something that I recommend to everyone to try....it gets expensive if yer wrong...and I have been once or twice, but only on ones that already had bearing damage.
