Diff bushing replacement

[VictorH]

I have to remove my muffler this weekend (going back to stock for now). Since the muffler will be off, what extra labor would I need to do to replace the differential bushings? I have the parts, have been sitting in my cabinet for >1yr waiting for the opportunity.

Do I need a bearing puller-like tool? Do I have to move the half shafts or just the drive shaft? Tips or a link to the DYI would be appreciated. Thanks

[pbonsalb]

Space is sort of tight with the subframe fully installed and the diff in place, so access will be a problem but I did not attempt what you are thinking so I can’t say for sure that it won’t wirk.

I did the diff bushings along with the subframe bushings with the subframe lowered maybe 6 inches. If you bought a meter of m12x1.5 threaded rod (off size so you will have to order on eBay or amazon) and some nuts, you could cut the rod into 3 pieces and replace the bolts with the rod to lower the subframe on what would be 3 studs, to give you getter access.

You need receivers and drivers to pull old bushings out and pull new ones in. I improvise but there are probably expensive special tools that fit perfect and make the job easier.

[Solo_M_Tech]

Diff has to come out and there is a special tool for removing the front bushings and a different special tool for removing the rear one. You're better off paying a reputable BMW shop to do it, since the labor is cheaper than the tools.

I've done this 50+ times and it's never a fun job.

[VictorH]

Originally Posted by ham_sammich

Diff has to come out and there is a special tool for removing the front bushings and a different special tool for removing the rear one. You're better off paying a reputable BMW shop to do it, since the labor is cheaper than the tools.

I've done this 50+ times and it's never a fun job.

Appreciate your insight. I guess I'm going to leave this alone. I thought it if was an extra 2-3 hours and no special tools I'd give it a shot but that doesn't sound like the case here.

[ec_E92]

Originally Posted by VictorH

Appreciate your insight. I guess I'm going to leave this alone. I thought it if was an extra 2-3 hours and no special tools I'd give it a shot but that doesn't sound like the case here.

I did diff bushings several years ago in my garage. I dropped the entire diff (remove axles at diff flange and input flange connection to driveshaft). You can get old bushings out by using a dremel or hacksaw blade and then punch out with a screwdriver. I made a press out of all thread, pvc and iron cups/plates from Lowe's. It is not a fun project, I cursed a lot and def more than 2-3 hours. A shop would be more efficient but I don't trust others to work on my car (and I have another car so can afford downtime on the M3).

[pbonsalb]

So the subframe stayed bolted in? The rear bushing is high up are seems like it would be hard to get to for pulling/installing without lowering the diff.

[Solo_M_Tech]

Originally Posted by pbonsalb

So the subframe stayed bolted in? The rear bushing is high up are seems like it would be hard to get to for pulling/installing without lowering the diff.

You can leave the subframe installed. It doesn't have to be lowered. I've done it that way every time. Easiest way to remove it is too drill out as much rubber as you can and then use a long prybar and a 3lb mini sledge to hammer out the center of the bushing. Then just bang out the outer ring, and then install the new bushing.


NOTE: install AKG or similar poly bushings or you will HATE your life for ever trying to press the new stock bushings in. I promise you.

NOTE2: I always install AKG or similar poly bushings when I do my diff services. Customer gets and upgrade and my job gets easier as well.

[ec_E92]

Originally Posted by pbonsalb

So the subframe stayed bolted in? The rear bushing is high up are seems like it would be hard to get to for pulling/installing without lowering the diff.

Correct. Not going to lie, the job was not fun but definitely doable. Replaced with poly (AKG) mounts.

[M3MPH1S]

I'm about to replace both the subframe and diff bushings with solid. Car has 155k miles on it. I was planning on replacing the 4 subframe bolts and 3 diff bolts, but haven't ordered them yet. Is it recommended or a waste of time? This car sees 6-8 track events per year. Main thought process is I've read about some people breaking one of their diff bolts. At $80+ for a few bolts, figured I'd get a second opinion first.

[Bartledoo]

Originally Posted by M3MPH1S

I'm about to replace both the subframe and diff bushings with solid. Car has 155k miles on it. I was planning on replacing the 4 subframe bolts and 3 diff bolts, but haven't ordered them yet. Is it recommended or a waste of time? This car sees 6-8 track events per year. Main thought process is I've read about some people breaking one of their diff bolts. At $80+ for a few bolts, figured I'd get a second opinion first.

I replaced all of the diff bolts since one was broken and they are clearly prone to damage, but reused the subframe bolts since they never have issues.