Pinion Oil Seal

Ok. This week/weekend my father-in-law and I tore out the rear axle/banjo/hubs, front hubs and brake rotors, and changed the Sprite from wire wheels to alloys. What a big project!! I'll probably make a post or a blog about that later.

Anyhow... We put the whole car back together without replacing that pinion oil seal... which, seemed to always have a minor leak. But as it turns out, it seems its much worse than I thought. It APEARS to be spraying all over everything thing while I'm driving.

I've attached a photo... I put an arrow pointing to the little "sleeve" on the differential... from which the leak originates. It then travels downhill on the casing of the differential, and finally drips off the drain cap. Because it's the lowest part of the car. I'm pretty sure the pinion oil seal is at fault here.

We're thinking of breaking her apart again tomorrow... guhh... but I need to know what size that nut is at the back of the differential. And if anyone can tell me what I'm in store for??? Torque settings would be greatly appreciated... and whether or not that nut spins standard (lefty loosey) or the other way around. Any other tips you can throw in, please do!

Thanks in advance!

...And a pic of the old girl with new wheels for good measure.

It's a big freakin' nut that's pretty freakin' tight, and yes it's lefty loosey. After you remove the "U" joint and get the driveshaft outa the way you can get it off easiest with an impact. Be warned tho', once you pull the yoke out, there is a distance piece between the back side of it and the bearing, and this HAS to be replaced before re assembly in order to get the proper pre load when everything is tightened back up. If you hate working upside down in tight places, pull the whole pumpkin out and do it on the bench.
A new seal and distance piece should set you right so long as that diff isn't making horrible noises.

BTW, the car looks good.

please do a search on the rear axle here, and on differential, because we've talked about this quite a lot in the last few months.


The pinion bearings will fail quickly if that nut is over tightened, and the factory used a one-time-use crush spacer to set it originally. If you replace that nut without using a new crush spacer, and torque to the 140 ft lb listed in the manual, you will certainly over tighten it. Over tightening this nut is like over tightening the fan belt and causing a perfectly good water pump to go bad (BTDT, in both cases).

If you remove it and try to re-tighten it to the same place you've got about a 50/50 chance of getting it right.

If you take out the differential and rebuild it on the bench (so you can replace that crush spacer) you'll greatly increase your chances of getting it. Ideally, you'll use a special torque wrench that goes down to 6 ~ 15 in-lbs and confirm that your pinion bearing pre-load is correct when you are done. This can also be measured with a small oz. scale and a lever arm, so I've heard some folks say.


Norm

oh, wait, I started an article on this subject. Here, check this out.
(no need to search, I tried to summarize what I learned this summer here)

Hope this helps,
Norm

Thanks for filling in the gaps Norm. It has been a while since I did mine, and I'm not as diligent as you at making notes.
I had been told a total rebuild of the diff was the only way to cure my oil leak, but a new distance piece and seal fixed it. I did do it on the bench though.

Some times ya just get lucky. I replaced my seal a few years back but I have the early rear with the solid spacer. I just tightened it back to where it was. It felt ok. Guess I was just lucky.

Dave

Norm, thanks for the article, as always your stuff is over the top(tu). If you EVER do a book put me down for one.;)

Paul