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Leaking 8" coming from the studs

939 views 12 replies 10 participants last post by  Woodchuck 
#1 ·
:frown2: So 2 months ago I completely tore apart my entire rear, including suspension, brakes etc to have the housing checked and straightened. While I was back there I noticed that my diff had been leaking.

Since I cleaned everything up when I reassembled I figured I would keep an eye on it and see if it did it again and sure enough it is.

It appears to be leaking right from a few of the studs that hold the carrier in.

I used new copper washers both times, a Felpro gasket, and a bit of right-Stuff silicone.

Iv'e never had a rear leak on me before using this method so twice in a row has me scratching my head. I like to keep the underside of my car as clean as the top so one way or another I have to get this sorted. I was considering pulling a few of the bolts and degreasing the studs as good as possible and then puting some silicone in the space between the studs and the holes in the carrier. Sort of "filling the hole" so to speak.

Can anyone give me any tips as to how to go about getting this thing sealed up?
 
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#2 ·
Is the leak coming between the washer and housing, washer and nut or up the threads between the stud and nut? You may need to clean one up and give it a liberal application of foot fungus spray powder to find out, exactly. If it's between the washer and housing or nut, then the soft copper washer probably isn't "soft" enough. If it's up the threads between the stud and nut then the washer I.D. may be too large or the stud/nut threads are whipped.
 
G
#3 ·
Whenever RTV is sued, regardless of which one . . you need perfectly clean metal. I love RTV, but unless you get it perfectly clean, it won't stick. I use lacquer thinner, to wipe down mating surfaces. If they are clean, it can't leak as long as you assemble within a reasonable amount of time. On threads, use threads locker. That way nothing will follow the threads out. Even a small dab of RTV will work on threads as well . . if clean :)
 
#5 ·
As Bartl said, make sure you have the correct washers. Close enough won't work.
 
#6 ·
Yes, the factory washers were VERY tight fitting over the studs....to the point where you usually have to chisel them off. None of the aftermarket "replacement" washers I've seen are anywhere near as tight as the OE washers.

There's a reason the factory went to thise lengths.
 
#8 ·
Axle vent isn't blocked and the hose is new. I only know because I cleaned it up inside and out when detailing the rear. The washers are tight but not super tight just like normal washer tight. So perhaps this is the issue. I may have the factory ones in a ziploc somewhere. Maybe a good idea to go back to those.

It's just annoying. I have probably done 100 gear sets etc and never had a problem with leaks. Driving me nuts. I was ridiculously careful to clean both mating surfaces too. Used some acetone I had left over from painting after scraping it all with a razor to get the old silicone off. I will clean it up over the weekend and try some powder to discover the true source and go from there.
 
#10 ·
I didn't use the copper washers and have zero leaks. those were annoying to remove and thought Id spare myself the hassle of ever having to do it again. The fella who setup my trutrac specializes in Ford and rock crawler rear ends and has for 25 years. He told me that he never uses them and doesn't ever have any issues. That's what I had to go on.

I felt washers were necessary so got some brass washers that were a good fit and thick enough so they wouldn't crush. I used some permatex high temp thread sealant on the threads just toward where bolt would go over it. Just a very thin film of ultra black on each side of gasket and also on each hard surface. then I dab my finger all over it to give it that tacky Velcro-like surface texture (something tells me it helps) torqued in stages and then came back 30 min later and torqued again

Based on my experience and the fella who does this every day for last 25 years, I have to conclude the copper washers aren't as essential to a good seal as the other methods described
 
#11 ·
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