What's The Fix? Weeping Differential Studs

[Keith R.]

Hey fellow NCRS'ers. I have a couple of differential studs that are weeping gear lube past the threads and onto the bottom of the differential. Have any of you encountered this before and if so, what's the fix? I am guessing that I would have to drain the differential, remove the studs and replace them using thread sealant.

[Mike M.]

Re: WTF - What's The Fix? Weeping Differential Studs

the flat washers should be copper. looks like you have mild steel flat washers. corvette central has the brass ones. mike

[Keith R.]

Re: WTF - What's The Fix? Weeping Differential Studs

Thanks Mike!

[Tom P.]

Re: WTF - What's The Fix? Weeping Differential Studs

As I have observed over the years, the 55-57 rears (BOTH pass cars and Corvettes) used regular nuts and COPPER washers. As the nuts were tightened, the copper washers crushed and deformed around the threads and underside of the nuts, thus, creating an oil seal. Then in 58 (again, both cars and Vettes) a change was made to nuts with a steel washer swedged into one side of the nuts. Those never did seal as well as the copper washers. NCRS CORRECT OR NOT-------------------for 58-62 Vette rears, the copper washers (in my book) are a superior choice. In time, if the nuts are periodically tightened a smidge, it just crushes the copper washers a little more and increases the sealing ability of the copper.

The copper washers are no longer available from GM. So you just have to shop around the auto parts stores (NAPA, O'Reilly, etc) and locate a suitable copper washer.

[Keith R.]

Re: WTF - What's The Fix? Weeping Differential Studs

Thanks for your input Tom. Much appreciated.

[Mike M.]

Re: WTF - What's The Fix? Weeping Differential Studs

tom: thanks much for the enlightenment. never noticed the 61 and 62's I've restored had the steel wedged washers.i've always used the copper washers, 54 thru 62 vets and pass cars i've restored, and NCRS never picked up on the copper washers on my 61 and 62. suggest Keith use the copper and if he's gonna run it thru NCRS judging, then hit the copper with cast blast or what ever paint he chooses to coat the differential with. learn something every dad. regards, mike

[Tom P.]

Re: WTF - What's The Fix? Weeping Differential Studs

---------------------------------------------------------------------------------------- and if he's gonna run it thru NCRS judging, then hit the copper with cast blast or what ever paint he chooses to coat the differential with. learn something every dad. regards, mike

Dang, that's an excellent suggestion. I've never thought of that --------------- but you know me, I'm not a numbers person, I'm a practical functionality person. For example, why have a correct 265 when you can have a disguised SB400 with FI, an airbox and Muncie.

[Joe L.]

Re: WTF - What's The Fix? Weeping Differential Studs

Thanks for your input Tom. Much appreciated.

Keith------


I would definitely use the copper washers as described. They remain available from GM under GM #21012386 which is a successor to the GM #14000172. The 21012386 actually offer improved sealing as they have circumferential, tiny grooves which compress and improve sealing. You could also obtain the original style washers in just about any good auto supply store in the brake parts section, but, if it were me, I'd use the 21012386. However, I would also thoroughly clean the threads on the studs and nuts and apply Locktite 242. Leak or not, I'd use the Locktite 242.

[Keith R.]

Re: WTF - What's The Fix? Weeping Differential Studs

Thanks Joe. Good advice! The TIMJ page 321 calls for thin copper washers to be used so I'll go shopping for the #21012386 washers as replacements and use the Locktite 242. Hopefully, that will be the fix. Much appreciated Joe.