Topic: Rear main seal STILL leaks ?!

[Shamb]

The rear main seal on the output shaft on the t-case has leaked for the past year. I put a new seal in when I had it out and got the freshly rebuilt L50 in. Immediatly after it started leaking so I pulled the flange off and it looks like it was leaking at the bottom where the metal outer part fits up against the rear of the t-case. So today I decided to go with a different brand seal.. basically the same thing.. this one was a tad bit bigger in diameter though so it fit nice a snug, before I installed it I also checked to see how tight of a seal it was going to make around the flange... seemed tight enough to keep 80-90 in there...

So I drive it about 5 miles just to test everything since i've been working on it and changing alot of other stuff around.  Get back home and its still dripping, I didn't pull the flange back off to see exactly where its leaking but there is definently a leak there still... about the same as the other seal...

Anyone run into this prob?  how'd you fix it?  am I doing something wrong here???

Also on a side note I noticed that since I have 3 leafed 63" chevys it allows the rear end to flex forward a little when I take off.. thus moving the driveline around and possibly the output shaft enought to leak?!?! ...

Im completely clueless.. thats the only explenation I could come up with so far.

[Duffil]

how does the flange look on the part that goes thru the seal?  Might need a new flange or a speedi-sleeve.

[Shamb [OP]]

looks fine.. a SLIGHT (if that)  bit of wear.. but nothing that would make it leak like it is..

before I installed the seal I slipped it over the flange and it was a good fit.

[MiniSimp]

did you add grease to the inside of the seal when you put it back in?

[toyrolet]

might be the output bearing is causing the shaft to be off center just alittle.  that would mostest definantly cause it to leak as you describe.

[Shamb [OP]]

yea thats true Toy... lets hope not.. lol.. i really dont want to tear into that anytime soon..

and yes Mini I did rub some oil/grease around the rubber seal as to make sure it doesnt crack or dry out.


When I installed the first seal it seemed as if it was leaking at the very bottom of the seal where the very bottom metal to metal contact was  (you know what i'm talking about?)

There's the in-set groove around 1/4" so the seal fits in there nice and flush, at the very bottom of the seal....

[derek]

did you put some silicone on the splines? it can leak gear oil between the splines if you dont put some rtv on them.
i put a little on the splines inside the flange to seal it up.

derek

[All_Set]

I installed a diff flange seal before where I got it too cocked eyed while installing it.  When I was done, I ended up fubaring the seal and it leaked almost immediately. (not alot, but it leaked) 

Pulled it back out.  Looked fine enough.  Replaced it, this time using sealant (grey silicone) around outside of metal seal, used grease on the rubber seal, and grey silicone on the splines(I put it on the flange side so extra sealant would be pushed out of the t-case on install).  Made sure to install it without cocking it and have had no worries since.

When you grab the flange how much is it moving?  Up to down and in and out?

Another thing to consider.  Is your driveshaft balanced?  My driveshaft was so wacked that @ about 70mph it would viberate enough to allow gear oil to slip out of the rear t-case flange.