Where to get differential seals for 2006 Z4M.

jontZ4M · Post by **jontZ4M** » Sun Jan 22, 2023 9:21 pm

Hi guys

My next job is to replace the front and side seals on the differential (front is leaking). I'm new to BMW, any idea how I go about locating these OE parts please?

Thanks

plenty · Post by **plenty** » Sun Jan 22, 2023 9:35 pm

Ring any BMW dealer with the part numbers.

Or search for online retailers using the part numbers.

https://www.realoem.com/bmw/enUS/showpa ... Id=33_1142

grannyknot · Post by **grannyknot** » Sun Jan 22, 2023 9:55 pm

The OEM input seal on the front of the diff is known leaker, you might want to go with something that seals better.
Racingdiffs has had their own seals made up for the front and side bearings, the seal spring is a thicker on theirs.

jontZ4M · Post by **jontZ4M** » Mon Jan 23, 2023 5:50 pm

Thanks guys. Also we do have a link to the official Z4M service manual on the forum somewhere? I've had a search but couldn't see it.

jontZ4M · Post by **jontZ4M** » Tue Jan 24, 2023 6:04 pm

Update:

I spoke to Racingdiffs. Their seal and bearing package is about £300 all in, which I'm sure is perfectly good value.

But as for the time being I only want to change the front seal or maybe all 3 seals, I think I'll phone BMW to see how much I can get the OE seals for.

jontZ4M · Post by **jontZ4M** » Wed Jan 25, 2023 5:10 pm

Guys, just planning ahead: when it comes to removing the flanges shown in the pic attached, I assume they are slip yokes, and just need pulling out? Any Do's or Do Not's that we know of? Thanks.

Spriteracer · Post by **Spriteracer** » Wed Jan 25, 2023 6:35 pm

You could try bearingkits.co.uk for the seals. I don't know for sure if they will sell seals separately, but I had a long chat with Mark (the owner I think) when I bought a full kit recently, and he was very helpful. Worth a call.

The flanges on my E86 3.0SI are pull out allowing access to the seals, as have most of the ones I've seen on various videos. They just tapped out with a suitable longish drift. Some have a bolted bearing retainer plate with the seal in it but the the drive flanges and this plate still pull out.

grannyknot · Post by **grannyknot** » Wed Jan 25, 2023 11:49 pm

jontZ4M wrote: ↑Wed Jan 25, 2023 5:10 pm Guys, just planning ahead: when it comes to removing the flanges shown in the pic attached, I assume they are slip yokes, and just need pulling out? Any Do's or Do Not's that we know of? Thanks.

The side flanges just pop out with pry bar or large screw driver, the front flange will need a 2-3 jaw puller or at least mine did.

Spriteracer · Post by **Spriteracer** » Thu Jan 26, 2023 9:57 am

You are probably aware of this but just in case... Make sure you mark the position of the pinion nut and number of turns before you take it off. Put it back in exactly the same place. If you overtighten you will change the crush spacer and the preload, the setting of which is critical for the life of the diff.

jontZ4M · Post by **jontZ4M** » Thu Jan 26, 2023 12:08 pm

Thanks guys

jontZ4M · Post by **jontZ4M** » Thu Jan 26, 2023 12:35 pm

Do we have a service manual available for the Z4M guys? I've had a search but can;t find anything decent. Need to get the bolt torque values from somewhere. Thanks.

Vanne · Post by **Vanne** » Fri Jan 27, 2023 11:57 am

You’ll find the part number list in my thread. Again.. if you’re swapping bearings, you’ll need a shim kit. It never goes back the same way. Either that or get someone who’s qualified to do the work. Summit racing have all the bits.

jontZ4M · Post by **jontZ4M** » Sun Jan 29, 2023 12:23 pm

Vanne wrote: ↑Fri Jan 27, 2023 11:57 am You’ll find the part number list in my thread. Again.. if you’re swapping bearings, you’ll need a shim kit. It never goes back the same way. Either that or get someone who’s qualified to do the work. Summit racing have all the bits.

I know I should take it to a proper mechanic to do this (I've even got £2k of warranty to use up) but I really want to give it a shot myself, as I love learning these things, as long as it's within a DIYer's skill limit.

I was only planning to change the pinion oil seal, nothing else.

I've played with Nissan diffs but nothing else. I assumed this diff would be similar in design.

As far as I understand, all I need to do is:
1) remove diff from car
2) mark pinion nut position and it's current torque
3) remove nut and pinion flange
4) remove oil seal(carefully)
5) clean it up
6) refit new seal
7) refit flange, tighten pinion nut to original position and torque +5 lbs/ft

put diff on car and torque prop and driveshaft bolts (if I ever manage to find the torque settings).

Does anyone think I've got this wrong or have somehow miss-understood the Z4 diff procedure?

Thanks a lot!

jontZ4M · Post by **jontZ4M** » Sun Jan 29, 2023 12:58 pm

FYI I've managed to find some info on the transmission bolt torque settings, not sure how reliable they are though. Difficulty finding Z4M torque settings in general is worrying me.

Pic 1 is from a E46 M3 website.

Pic 2 is from a generic Z4 service manual.

maupineda · Post by **maupineda** » Sun Jan 29, 2023 6:11 pm

I have ISTA+, if you need any torque value, let me know here or in a DM

Z4-forum.com

Z4-forum.com