I apologize if this has been mentioned already elsewhere over the preceding ~20 years, but I had trouble online finding the information I needed to replace an axle seal on my 2005 R50's manual Getrag gearbox. (I can't speak for other Gen. 1 models or transmissions.)

After replacing a bad CV axle I had a bit of a tough time getting the new axle installed and, as it turned out, damaged the axle seal (the drips of brand-new gear oil in my garage were my clue). (I replaced the driver side, left-hand drive, axle a couple of years ago and it went much more smoothly.)

This was the first time I would have to install an axle seal. My first mistake was buying two genuine BMW seals from a vendor that tends to charge more than the others. My second mistake was following some incomplete advice I found online and gently tapping the new seal into the transmission housing by banging directly in the seal with a small hammer, thereby bending the housing and wrecking not one, but also the second seal I ordered in case I buggered the first. Some swearing ensued because I'd spent $100 USD for the two seals.

Using my brain, I measured the seal with a caliper and determined that instead of spending a significant amount of money on a BMW installation tool, I could go to the hardware store and get a 2" "plumbing pipe thingy," which fit the outside diameter of the seal (the blue ring) perfectly. After wrecking two seals and express ordering four more (non-OEM and 50% cheaper) because I was traumatized and wanted some spares, a few whacks with a 3-pound steel hammer and the new seal was seated. It didn't want to go in straight, but I got it as close as I could and then just whacked it to finish the job. Note that I also removed the flywheel cover that resides to the right the axle housing (held in with two 10mm bolts) for a bit of extra clearance. After some 40 miles of test driving at speeds both legal and illegal and a piece of cardboard under the transmission overnight, no drips. Pictured is the 2" "plumbing pipe thingy" I used. Hope this helps.

 

Timely post, I was just reading about this repair earlier today and searching for seals, as we have a leak coming from the driver's side of the diff on the R50. I, too, saw the advice of not using a tool and thought it was odd. The tip to use a 2" pvc plumbing reducer seemed to make sense. I'll buy a couple of the Getrag seals and hopefully it won't be too difficult.

 

Cool. Yeah, I had a similar PVC part in my hand at Home Depot today but ultimately decided to go for the metal part as it has an obvious striking surface. I think the part I bought is cast iron as it's pretty heavy, so make sure you're not smiling up at it if you get one as I'm sure it would take some teeth out if it fell on your face! 😁 Also, I didn't mention it (and I don't know if you need this guidance but it has been mentioned elsewhere), removing the power steering cooling fan frees up the room you'll need. Good luck!

 

Ha, that's why I was looking at PVC and putting a cap on the pipe, rather than cast iron. Dropping that wouldn't be fun.
Was just under the car replacing the power steering pump, as well as struts, shocks, and the fuel hard line (from tank to fuel rail) which is when I saw the leaking, so yeah, removing the fan will be necessary to do the passenger side. I had to partially drop the subframe (loosen enough that I could pry it down) to install the fuel line. 305k and still going strong though.

 

You have 305K miles? Wow! I'm at 150K and am debating whether or not I want to go with a brand-new built engine, or rebuild mine myself but add a ported-and-polished head. My engine is still going strong and has an upgraded cam (in addition to exhaust and ECU mods), but having a bored-and-stroked engine delivered to my garage is appealing (although very expensive, I know). But doing the work myself is better aligned with why I still have this car in the first place. I've had the front subframe out a couple times and it's not that bad; you just need to be careful to disconnect the electrical connections before dropping it too low, and you need to keep the power steering reservoir upright while the subframe's out or it will leak if it's left flopped over (there are YouTube videos that detail the procedure). Great opportunity to replace upper control arm and sway bar bushings, etc.

 

Just an update to my post about replacing the CV axle. Hope this will help anyone else who's been in a similar situation.

The car did develop a leak about 24 hours after I posted above. I was concerned it was the non-OEM axle I purchased (some have tolerance issues), so I ponied up for the genuine article and installed it with a fresh Getrag seal. I was very careful to slide the new axle in gently so as to not damage the rubber seal (it took a bit of turning the axle and the driver-side wheel before it would go in without resistance), but, after a vigorous test drive, it STILL leaked.

So this weekend I drained the brand-new fluid (again... I tried to save it but decided to just replace it with new... again), pried out the seal and removed the axle to do it all over again.

I was carefully inspecting the "socket" on the transmission housing and noticed that I'd caused a very slight gouge on the top of the mating surface when I pried out the old seal with a pry bar. More of a scratch than a gouge... it didn't look like much... maybe 0.25mm deep. But when I examined the seal I'd just removed, the outer edge of the seal (the blue, metal part) had oil on it, and it looked like this was where the leak was coming from, not the inner rubber bit.

So with my finger I spread a thin film of red rtv over the scratch and over the entire outer edge of the new seal before pounding it in. Reinstalled the axle, added new fluid and have done a couple of 100km test drives over the last couple of days and no leaks. So, it appears to be fixed... finally.

As of this moment, everything's 100% on my 2005 R50. Let's hope it stays that way for a while. It's like a brand-new car, one piece at a time. 😄

 

Many thanks ATK