Did I mess up? Differential pinion seal (would you guys re-do it?)

[M3S54E46]

Hello, I was installing my rear differential pinion seal and It accidentally went in too far (it sits a tiny bit less then 1/8" inset). My intention was to set it in as before so roughly 1/32" in, however I was not being careful enough I guess. However I was wondering if anyone sees any issue with leaving it as is? I inspected both contact points and the seal is sitting on the two surfaces that it should (no issue), I also pushed hard with my finger and it doesn't budge so its sitting firm. Maybe a bigger concern is that it may be partially blocking a return port (not sure though since its only a little more in then before)

One picture shows how it was set in before, one shows how it is set in now.

Would you guys replace it or leave as is?

Thanks!

[M3S54E46]

Here is the before seal, and how it looks like inside.

[chalaka]

tough choice..
spin it couple times, does it leak?

may add some kind of sealant around the seal and leave it like it...

[Casa de Mesa]

cobra may have your answer. If it's anything like a front main seal (same basic principle/design) I think it might actually be better at a slightly different depth. My thought is if nothing is rubbing and the seal is in good shape, you might actually be better off. PTFE seals form a groove on the pinion (or crank with the front main seal) and you actually want to mount the seal at a slightly different depth. I'm not 100% sure this is true with the pinion seal, but I'm pretty certain you're fine.

[Casa de Mesa]

tough choice..
spin it couple times, does it leak?

may add some kind of sealant around the seal and leave it like it...

Adding sealant to a radial seal will have zero impact to the seal's viability. It may actually make things worse.

[chalaka]

Adding sealant to a radial seal will have zero impact to the seal's viability. It may actually make things worse.

oops. .
lesson learned. Thanks Casa de Mesa

(will it be better if applied around the seal during seating it? recalled some youtube video showing adding something around it .. well, may be my bad memory)

[Casa de Mesa]

oops. .
lesson learned. Thanks Casa de Mesa

(will it be better if applied around the seal during seating it? recalled some youtube video showing adding something around it .. well, may be my bad memory)

The seal will leak where the inner portion of the seal touches the spinning pinion shaft. If you apply sealant there, as soon as the pinion turns, you'll break the sealant. If you're talking about putting sealant on the outer perimeter, there really is no point. As far as I know, they do not leak there, unless there was a major issue with the install or something is wrong with the differential housing where that seal recesses into.

[Rich022]

You’re probably okay. I just did mine recently and FYI bmw does make a pretty cool seal driver tool to properly push in and set the seal. Part 83300495593. FCP Euro carries. Was worth it IMO. I also went with the aftermarket Corteco seal which uses a spring to maintain tension around the seal.

[M3S54E46]

Hello All, Thanks for the feedback! I used a genuine bmw seal (it also has a spring to tension the inner seal). I had a look at both contact surfaces of the seal, and both of them lie on the same machined surface(same diameters) as if the seal was in the correct position so I know the seal will be sealing correctly. Also I made sure to measure the distance that the seal is set in is the same all around. Buying a new seal will mean the car will be on jack-stands for at least another week, so I will roll with what I have for now. I should have been more careful (lesson learned), and will let you guys know if anything bad happens.

Thanks again

[Rich022]

That’s good to hear!

[bigjae46]

You should be OK. The oil drain is about 1/2 deep IIRC.

Do NOT apply sealant to a radial seal. There is a spring inside the inner lip of the seal which applies tension and seals against the shaft.

Radial shaft seals will alway leak…eventually.


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[sapote]

Maybe a bigger concern is that it may be partially blocking a return port (not sure though since its only a little more in then before.

There is no oil ports or anything next to the seal to concern. Did you lube the the OD of the seal before pushing it in, and the pinion flange sealing surface before pushing it through the seal?

[sapote]

The seal will leak where the inner portion of the seal touches the spinning pinion shaft..

I'm sure you meant the pinion flange.
This begs the question: why the oil doesn't leak through between the flange and the pinion shaft spines?

[sapote]

OP, how much torque did it need to set the nut to its original marked position?
How much force to slide the drive flange on the pinion shaft?

[Casa de Mesa]

There is no oil ports or anything next to the seal to concern. Did you lube the the OD of the seal before pushing it in, and the pinion flange sealing surface before pushing it through the seal?

I'm not sure who you quoted in your 1st post above, but it looked like I wrote it the way you quoted me. However, I never typed that.

Also in your 2nd post sapote , correct I meant the splined pinion flange that bolts onto the CV of the driveshaft on one side with 6 bolts (or is it 8?) and slides onto the pinion splines and is retained by the pinion nut that must be torqued back to where it was. Regardless, sealant should not be applied to the pinion seal was the only point I was attempting to make.