Pinion seal leak

[Axle_Foley]

'81 Pontiac Firebird Formula with it's original 10 bolt 8.5
104K miles on it.

No gear noise but had some bearing noise and a real bad pinion seal leak when I got the car recently.
Took a close look at it. Noticed someone recently replaced the seal.

Definitely not leaking thru splines. It's past the seal. Flung on the tunnel and leaks when parked. Drips from behind flange on ground and runs to the cover and drips.

So, took it apart and changed the seal again using a NOS seal that even had a thin bead of sealer around the outside of the seal. Seal installed tight and thought all would be well.

Nope. Still leaked bad.

Just picked it up today from the drive line place because it needed new bearings anyway. Gave them another NOS seal and made them aware of the issue.

Brought it home and put it on jack stands at a slight angle and added about 4-6 ounces of gear lube. Leaks like a m-effer still.

When I tore the diff down before I dropped it off I inspected the seal area for any potential issues. Cracks, gouges, etc. Nothing.

Pinion flange is not grooved either. Look at the pic......it leaked THAT much at a slight angle in less than an hour.

WTF. Makes no sense. Is there an upgraded double lip seal available?

[monzaz]

ANY chance you want to do this job?
Remove the pinion yoke, see if you can remover the seal with out damaging it. IF it is a flush mount ...there is no way to remove it with out destroying it.
IF the seal has a lip edge that seats on the casting then you should be able to screw driver the edge and tap and pry little at a time to remove it from the machine hole.
Or
Buy the same seal and feel how it is on the yoke seal surface area. whether you can tip it at angle easy or not. IT should fit fairly tight and only go on squared to the seal.

They also sell redi repair sleeve for this 1.94" seal surface yoke and increase the outer diameter of the yoke seal surface.
You can also buy a NEW 8.5 late 99 yoke with the GM triple lip teflon seal combo...
It really freaks me out that you say the seal surface does not have a groove...MAYBE someone machined or sanded the seal surface so much it is under sized? or the seal your buying is just plain defective.

I really need pictures and it would be nice to feel the seal on the yoke preinstalled (before installation).
IF you do remove the yoke PLEASE take pictures of the seal installed in the snout of the rear end befre trying to remove ...just want to see. top and side shots.

Jim

[Axle_Foley]

Jim thanks for your reply.

I may need your help with this issue later but for now I took the rear back to the shop who assembled it to see what they can do. I didn't want to disassemble anything until I gave them a chance to fix it. I told them there was an issue with a leak from the pinion seal when I first took it there and to give it special attention but obviously they didn't.

I will post an update here as soon as they get back to me. If they fail we will go into it deeper. The only pic I took before taking it back to them is this pic of what appears to be it leaking from between the shell of the seal and the housing on the driver side. Maybe I am wrong but it sure looks like that and it isn't wet on any other area of the outside of the seal accept for where it ran down to the bottom of the housing and dripped on the floor.

Do you have a part number for that late '99 8.5 yoke with the teflon seal?

[monzaz]

That is why we ALWAYS always use RTV on the OD of the seal metal surface that meets the housing ID surface. There might be a screw driver pry scrap in your housing casting where the seal meets the housing casting machined surface. WE run into this alot. BACK yard mechanic screw driver pry bar issue...LOL. Jim

[Axle_Foley]

That is why we ALWAYS always use RTV on the OD of the seal metal surface that meets the housing ID surface. There might be a screw driver pry scrap in your housing casting where the seal meets the housing casting machined surface. WE run into this alot. BACK yard mechanic screw driver pry bar issue...LOL. Jim

When I disassembled the rear before dropping it off at the rebuilder the first time, I saw marks just like you describe on the inside of the housing where the seal goes,as if someone at one time jammed a screwdriver in between the seal shell and housing to pry the seal out.

I didn't think much of it because they were not deep, couldn't even catch a finger nail on them. I didn't even smooth them over with some crocus cloth which is what I should have at least done.

Maybe this is the leak source, I hope so as it should be an easy fix. Have not heard back from the shop yet in the three days since I dropped it off.

[monzaz]

As stated. RTV black silicone on the outer edge of the seal then tap it into the housing... IT WILL stop that score leak.
Jim

[Axle_Foley]

Just got a call from the driveline place.
I am not sure what they tried to fix the leak as I won't be able to talk to them until tomorrow, but they claim the only way they were able to stop the leak was to replace the flange with a new one and use an "updated" two piece seal.

Can you clue me in to what that is exactly?

[monzaz]

only thing i can think of is they are just using GM NEW 8.5 /8.6 yoke with the stainless seal surface on the yoke and a teflon 2-3 lip seal.

It is all like 1996 newer parts -
will see if it stops the leak...HOW much was all that stuff?

[Axle_Foley]

HOW much was all that stuff?

Flange and seal 120 installed.

[monzaz]

Not terrible...Could have been worse. Problem solved? Hopefully Yes...? Jim

[Axle_Foley]

Had the rear on jack stands nose down with some gear lube in it for 2 days and no leak. Have yet to put it in service but I am hoping it'll be good to go.

[monzaz]

Crossing my fingers for you. Sounds good so far.
Jim