TR2/3/3A TR3 pinion seal - leaked from sitting will it reseal?

I have a question. My TR3, for a variety of reasons, ended up sitting for about three + years, some of you may recall I did a fairly extensive posting on my build a few years ago but then dropped off the board. Anyway things are back on track and now I’m ready to do the first shake down drive.

When the car was put away, it had a brand new pinion/differential seal. But over time differential fluid leaked out from the front pinion seal. My first inclination was to pull it out and replace it. But then I got thinking, maybe if I refill the differential seal it will seal itself just by finally using the car. Maybe just the sitting caused it to leak? I did a check of the other threads - lots of info on replacing the seal but nothing on this topic.

Am I dreaming or could this be a possibility? I get it that it may weap a bit, I can live with that.

Thanks in advance, luke-44

I think it unlikely that "just sitting" for 3 years caused the leak. Also unlikely it will magically heal itself.

But, a bit under a quart in 3 years isn't much of a leak. So I would at least try filling it up and seeing how bad the leak really is. Just don't let it get too low.

If you do want to pursue it, first make sure it's the seal that is leaking. Then when you do change the seal, use a Speedi-Sleeve on the flange. Be sure to lubricate both the surface of the flange (now the Speedi-Sleeve) and the lips of the seal generously before reassembly. A little dab of your favorite sealant under the big flat washer wouldn't hurt anything either.

I had a similar problem and when I removed the pinion flange I found the sealing surface badly pitted so I cleaned it up with some emery cloth and to be sure I used gasket cement on the spline and large washer, it hasn't leaked since, touch wood.

Graham

The original seals get really, really stuck, and when they are removed the pry bar devil that archetypically lives in everyone will take something like a small pry bar/ screwdriver and push that something between the seal and the case and pry. This method usually leaves a scratch in the case that leaks. This information is non-applicable if you did it yourself.

Anyways, I would look real carful at the case and determine whether the leak is in the rubber/plastic lip of the seal or between the case and the frame or outer shell of the seal itself. If by chance the leak is at the case, you might be able to fix it with silicone or something like that. The trick is getting the area clean enough for the glue/sealant to take hold.

steve

I’ve never had a seal “ fix” itself.

I wasn’t really expecting it to fix it’s self of course, but like Randall said if you consider slow dripping over three years maybe it’s not all that bad. What i was wondering is whether the seal could have dried out over time, and when I fill the dif back up, it would wet out and work better. It was a brand new seal that never leaked for the first 3 years I was building the car and somehow, zero miles later, it leaks out over years 4-6.

I think I’ll fill it up and monitor it. Worst case is it still leaks beyond an acceptable amount and I have to change it out.

At least the seal can be replaced without removing the diff.
Berry

I suppose it is possible for seals to dry out...but this one is always wet, unless you have drained the oil from the diff. As with any leak, accept it until you have the time and "want to" to fix it. It'll run forever with a small leak!

Just to close out this thread, it turns out what looked like a big puddle of total diff drainage was actually nothing more than a slow leak over time that looked far worse than it was. A quick check showed the diff was much closer to full than I could have ever imagined. Mystery solved.



I topped it back up and good to go. And strangely, no drips after driving and reparking, go figure. Thanks Randall for the input.

Luke:

Did you top it up so it overflowed the filler plug opening or to some distance below the filler? I recently drained the diff on my TR4A SRA, which can only be done by removing the cover, and the 1.8 liters to refill did not overflow. Or else I mis-measured....

Yes to the point it started to run out the filler plug opening. Maybe I’ve been over filling it all along?

Andy Blackley said:

Luke:

...the 1.8 liters to refill did not overflow. Or else I mis-measured....

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I expect you mean 1.8 U.S. pints.

I always fill till it flows out but best not to overfill (can happen if the rear is elevated) as the extra may get past the seals in the axles.

Quite right. Nearly an entire quart bottle.

Geo Hahn said:

I expect you mean 1.8 U.S. pints.

I always fill till it flows out but best not to overfill (can happen if the rear is elevated) as the extra may get past the seals in the axles.

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