Differential Side / Axle Seal DIY?

[Owens84qv]

While inspecting the underside of the M3 this weekend, noticed the passenger-side Differential side / axle seal was leaking. I searched for a DIY to replace this and wasn't able to find anything. Anyone know of a DIY?

Thank you!

[ec_E92]

Don't have a diy and no affiliation but check out bimmerdiffs.com for parts. I tore apart mine several years ago for a failed input shaft bearing, it's not hard but not easy either.

[WingZeroX5]

My guess is to remove the output shaft via the 5 torx bolts, drain your diff, then undo the hex bolts, and replace 8-12 http://www.realoem.com/bmw/enUS/show...diagId=33_1418

You could probably get away with just replacing #12, but it's a "while you're in there" type of job so why not do the rest?

Refill your diff fluid

In order to drop the output shaft, you're going to have to drop the exhaust too

[e92zero]

I don't have a DIY but I just did this on both my left and right seals not too long ago. You can reference any BMW Diff seal replacement diy/video online as they are pretty much the same:

- drop exhaust
- remove the 6 torx bolts for the drive shaft (along with the plate), they are suppose to be one time use only. Tightening torque are 120 Nm.
- pry off the flange, should be easy
- I was not able to remove the seal from the covers here while it's still on the diff so I ended up removing the cover as well. 8 hex bolts. Tightening torque are 21.7 Nm. This cover fits very very tightly and is there to actually position and hold the diff gears inside. If you do take off this cover, mark the orientation as there is a breather/oil supply hole inside. (I am not sure it matters as long as it's up but just mark it so you can put it in the same). The shim is also specific to the individual side so don't mix them (left vs right if you are doing both seals).
- I ended up having to use a press to remove and install the seal on the cover. Note how far the seal goes in. It is NOT suppose to bottom out and only cover the oil supply hole maybe 1/2 way. You will know what I mean after you look at the cover more closely. Just remember how far in the old one was and press in the new one the same depth and you will be fine.

Put everything back in reverse order. It's gonna be very hard to put a torque wrench in there to tighten the 6 torx bolts if you are working on it under the car. Having someone to help you hold the brake while you rotate the flange/shaft would save you a lot of time and backache. I didn't have help so I have to rotate wheel, get in car, pull handbrakes, get back under and tighten the bolts in cross patten. Repeat for all 12 bolts at a 3 step process because I don't want to tighten them to 120 Nm in one shot. My back was not happy.

Good lucky and let me know if you have any questions.

[mharris2007]

Originally Posted by e92zero

I don't have a DIY but I just did this on both my left and right seals not too long ago. You can reference any BMW Diff seal replacement diy/video online as they are pretty much the same:

- drop exhaust
- remove the 6 torx bolts for the drive shaft (along with the plate), they are suppose to be one time use only. Tightening torque are 120 Nm.
- pry off the flange, should be easy
- I was not able to remove the seal from the covers here while it's still on the diff so I ended up removing the cover as well. 8 hex bolts. Tightening torque are 21.7 Nm. This cover fits very very tightly and is there to actually position and hold the diff gears inside. If you do take off this cover, mark the orientation as there is a breather/oil supply hole inside. (I am not sure it matters as long as it's up but just mark it so you can put it in the same). The shim is also specific to the individual side so don't mix them (left vs right if you are doing both seals).
- I ended up having to use a press to remove and install the seal on the cover. Note how far the seal goes in. It is NOT suppose to bottom out and only cover the oil supply hole maybe 1/2 way. You will know what I mean after you look at the cover more closely. Just remember how far in the old one was and press in the new one the same depth and you will be fine.

Put everything back in reverse order. It's gonna be very hard to put a torque wrench in there to tighten the 6 torx bolts if you are working on it under the car. Having someone to help you hold the brake while you rotate the flange/shaft would save you a lot of time and backache. I didn't have help so I have to rotate wheel, get in car, pull handbrakes, get back under and tighten the bolts in cross patten. Repeat for all 12 bolts at a 3 step process because I don't want to tighten them to 120 Nm in one shot. My back was not happy.

Good lucky and let me know if you have any questions.

Super helpful description for all of us. Thank you.

[Theodore]

For cross reference, here is a link to a DIY guide for this job.