Differential Stop-Leak

[Dale .D]

Eh every one. Looking for some advise on the best stop leak additives for my rear end GT. Thought it was a pinion seal So had that replaced & it didn't stop. Wanting to try some kind of stop leak product & see what happens.Thanks for your replies.

[guyopel]

I have not seen any stop leak for the diff. , best to replace the seals or check for and replace worn part that the seal is on .HTH

[kwilford]

Originally Posted by Dale .D Eh every one. Looking for some advise on the best stop leak additives for my rear end GT. Thought it was a pinion seal So had that replaced & it didn't stop. Wanting to try some kind of stop leak product & see what happens.Thanks for your replies.

No such thing that works, and it is a total waste of time to try it.

When you replaced the pinion seal, did you (or the shop that did the work) inspect the outside surface of the driveshaft? It is possible that the sealing surface is scored or grooved by wear, and you will need to repair it with a sleeve (I think they are called Redi-sleeves, and are available from any decent seal and bearing shop in virtually every size imaginable). Or it could be as simple as the new seal was improperly installed.

HTH

[Dale .D]

Hi Keith.You could be right about the faulty installation.Our local shop is not up to par as late.Very frustrating when things come back worse after paying through the nose.Wish I was more mechanical.. Was hopeing to try a stop leak of some sort before getting the shaft again.

[Dale .D]

Originally Posted by kwilford No such thing that works, and it is a total waste of time to try it. When you replaced the pinion seal, did you (or the shop that did the work) inspect the outside surface of the driveshaft? It is possible that the sealing surface is scored or grooved by wear, and you will need to repair it with a sleeve (I think they are called Redi-sleeves, and are available from any decent seal and bearing shop in virtually every size imaginable). Or it could be as simple as the new seal was improperly installed. HTH

You are probably right keith but I'm going to try a stop leak before I get into it. My research has come up with A LUCUS product called lucus engine stop leak that is also reccomended for differencials at a 20% of product to gear oil. I'm useing 75\90 liquid Purple.Doing it today. I'll keep this thread updated as to what happens

[Dale .D]

Originally Posted by kwilford No such thing that works, and it is a total waste of time to try it. When you replaced the pinion seal, did you (or the shop that did the work) inspect the outside surface of the driveshaft? It is possible that the sealing surface is scored or grooved by wear, and you will need to repair it with a sleeve (I think they are called Redi-sleeves, and are available from any decent seal and bearing shop in virtually every size imaginable). Or it could be as simple as the new seal was improperly installed. HTH

Smart ass!. Your right again. Must be all those chinooks last winter.They were cool when I live there.Best part was Edmonton didn't get them.Ordered 2 pinion seals just in case. A friend recommended a german shop in Duncan so I'll give them a try. THe stop leak & expensive oil leaked out like a sive.I've printed your email to put in the car when I take it in . Going to be tight.Getting fixed on fri & a show on Sat in Qualicum. 600 cars .Should be fun .Wish me luck on the fix . Take care. Dale

[kwilford]

Sorry it didn't work Dale. From what I understand, the "principal" behind stop-leak products is that they contain solvents that "soften and swell" old, hardened rubber seals and gaskets, which SOMETIMES can cause them to seal. In your case, with a "new" seal, the rubber shouldn't be hardened, so no way for it to work it's "magic". But the principal reason that leak-stop products are on the shelf is to get desperate owners to give them a try before they give up and fix the leak properly.

IIRC, a leaky pinion seal was one of the first things I ever fixed on my GT, way back in about 1977. The Buick dealership didn't have them in stock (imagine that!) so I gently pulled the old one out and took it down to the local B.C. Bearing and Supply store, which they matched up right off the shelf (standard metric size IIRC). So long as the drive shaft doesn't have a groove or pits in the sealing surface, it's a pretty easy job. Hmm, I take that back, as you have to remove the torque tube, which is one of the nastier jobs to do, especially by yourself. It's been a few years, OK, a few decades, but IIRC, here's a few steps in the process. When I look at the FSM's I have, and even the Chilton's, Autobooks and Glenn's Repair manuals, they don't provide a very good step-wise instruction, so hopefully this may be of help (and all the rest of the more current Opel mechanics on-site can chime in ).

First, you remove the drive shaft rear U-joint, and support the driveshaft still in place in the transmission so it doesn't spill its oil out (unless you take the opportunity to replace that seal at the same time, which isn't a bad idea).

Then you remove the two big bolts that attach the central joint to the body. Nasty job, as the differential will want to swing down unless you have it properly jacked so as to relieve the downward force. In other words, make sure you (or the shop) does this, otherwise they will get a nasty surprise when they remove those bolts. Make sure that the washers and spacers are kept in order and in the correct place for reassembly.

GENTLY allow the torque tube and central joint assembly to swing down (hmm, I think you also have to watch out for the rear brake line) and then remove the four triple-square socket-head bolts that attach the torque tube to the differential. I usually replace these bolts with standard metric M8 socket-head cap screws, which are standard (and more durable) Allen-head. Then gently slide the torque tube and rear dive shaft forward, out of the differential housing, exposing the seal. Replace the seal by prying the old one out with a screw driver, and using a proper drift (I think I found a very large socket the correct diameter, but a seal installation tool is the tool of choice) drive the new seal squarely into the differential housing.

Inspect the rear driveshaft (correctly called "the drive pinion extension shaft", which is inside the torque tube) end that goes into the seal for grooves or pits. It can be "dressed" (made smooth if it has minor grooves etc) with fine Emory cloth, otherwise a Redi-sleeve has to be installed to R&R it. To do that, the shaft may have to be removed from the central carrier, which is another set of instructions.

HTH and good luck.

[opeldean]

Here is my latest leak that started out of nowhere.

It looks like a big job to the repair correctly, as I read this thread. I just want to drive...

Question: Why cant I just clean it up and Seal it with JB Weld or whatever around the perimeter as I have drawn in yellow.

[GTJIM]

Originally Posted by opeldean Question: Why cant I just clean it up and Seal it with JB Weld or whatever around the perimeter as I have drawn in yellow.

What has probably happened is that the four bolts have slightly loosened (with all that extra horsepower!) and the seal across the mating face has been opened up. There should be a thin paper gasket between the end of the torque tube and the front face of the diff housing.

Just re-tightening the bolts to the correct torque (don't 'wring their necks' !) may reduce the leak - but to fix it properly requires some sealing between the cleaned and oil-free faces - not just smeared on the oily outside of the joint ...

[RallyBob]

Originally Posted by GTJIM There should be a thin paper gasket between the end of the torque tube and the front face of the diff housing.

There's actually not supposed to be a gasket there at all. The leakage is via the front pinion seal that surrounds the torque tube shaft. You definitely want to fix this, as low differential oil levels can result in failed pinion bearings...extremely expensive to repair! A pinion seal is maybe $10, plus an hour to swap it out.

Bob

[kwilford]

Originally Posted by GTJIM What has probably happened is that the four bolts have slightly loosened (with all that extra horsepower!) and the seal across the mating face has been opened up. There should be a thin paper gasket between the end of the torque tube and the front face of the diff housing. Just re-tightening the bolts to the correct torque (don't 'wring their necks' !) may reduce the leak - but to fix it properly requires some sealing between the cleaned and oil-free faces - not just smeared on the oily outside of the joint ...

Jim Jim Jim...

If you look closely, you'll see that the torque tube housing actually has a drain built into it: that small piece of curved sheet metal welded to it that is open to the rear. That is to show that the pinion bearing is leaking rather than just collecting oil inside the housing. If oil is coming out of the drain, or from the joint, then the pinion seal needs to be replaced.

[GTJIM]

Originally Posted by kwilford Jim Jim Jim... If you look closely, you'll see that the torque tube housing actually has a drain built into it: that small piece of curved sheet metal welded to it that is open to the rear. That is to show that the pinion bearing is leaking rather than just collecting oil inside the housing. If oil is coming out of the drain, or from the joint, then the pinion seal needs to be replaced.

That is what I love about this site - always learning something new!

Guess I can stop making those fiddly wee gaskets now!