Anybody dropped the rear subframe???

[Robert K]

I'm considering dropping the entire subframe in my 1991 535i to replace subframe bushings, diff mount bushings and control arm bushings. Anybody done it? Just wondered how heavy the whole thing is and how difficult it is to remove and replace.

Grace and peace,

Robert K
1991 535i

[pyro]

im going to be doing this same thing VERY soon... had a few questions myself so ill ask... At work we have a universal puller that has many adapters... Can you remove the bushings with that? or do you need the bmw tool? and what is the rear sub frame bushing actually calld so i can order it from our parts supplyer.

[l8apex]

I removed the rear subframe when I installed my 3.46 Quaife diff. Re-did all the bushings while it was out. I also removed the drive shaft to replace the guibo and center bearing at the same time. If you aren't completely removing the drive shaft for the same, or similar reasons, you can probably unbolt the driveshaft at the diff, the two subframe mounting bushings, the diff mount at the body, rear shocks, brake lines, a few wires, and emergency brake cables and lower the whole assembly. I found that removing the emergency brake cables was the hardest part of the job. Eventually, I just unbolted the rear brake backing plates and let the cables and plates dangle.
It's not too heavy with a floor jack, but I wouldn't want to try manhandling it with the diff in place.

[Kobe Diesel]

when you have it all out, consider renewing the rear wheel bearings.

[E34-520iSE]

I agree with l8pex. It's pretty easy dropping the subframe. I did mine with the diff bolted to it. I too found the handbrake (e-brake) cables slowed me down a bit, as I had to unclip it from the shoes. A decent trolley jack will hold the complete subframe no problem - it's not that heavy.

HTH,

Shaun

[Robin-535im]

I'm considering dropping the entire subframe in my 1991 535i to replace subframe bushings, diff mount bushings and control arm bushings. Anybody done it? Just wondered how heavy the whole thing is and how difficult it is to remove and replace.

Grace and peace,

Robert K
1991 535i

Hi Robert,

I did exactly that on my 535 last year. Here's what I can remember:

1) go ahead and remove the last 1/2 of the exhaust, it's possible yet a huge pain to work around it.

2) Removal and installation is very straightforward. Be sure to disconnect the speed sensor cable, because once you loosen the subframe it'll snap like a twig. Ask me how I know...

3) Swapping the trailing arm bushings is not easy. Don Gale helped me out a huge amout by cutting a special pipe just long enough to span the inner legs of the trailing arm, so that you could put it on a press and the pipe would take the force instead of risking a bend trailing arm. A shop might have better tools, but it took many tens of tons of force to remove those suckers, and thats after heating it up with a torch!

4) Think about M5 bushings... I don't know if they are different but might be a nice upgrade.

5) Clean all the gook out of the half-shaft bolts really good with a wire brush or something. Those allen bolts have a tendency to strip if your driver is only 1/2 way in. Mine were filled to the brim with muck.

6) Check your half shafts for play while you're in there, and think about replacing them if the aren't tight.

7) Consider replacing the diff side flange seals while you're there. Cheap and easy to do.

8) Careful with the brake lines: keep all the bits and peices in order and try not to bugger up the nut faces like I did! Rigmaster had to send me a new brake pipe after I was done working my magic.

9) It's not too heavy if you pull the diff and half shafts first. Kind of have to wiggle it back in if the driveshaft is still on the center bearing, so plan on using those beach muscles a bit. In retrospect I would have dropped the driveshaft too, it would have been faster and easier. The tail end of the DS has to fit into the hole in the subframe, yet the subframe mounting points (beercan bushings) have to fit in their slot at the same time. Alternately you can probably pop the subframe bolts up from the bottom to get them out of the way, but I didn't want to disturb the little tar patches atop the bolts yet again.

HTH

- Robin

[Robert K]

Can you expand a bit on how you did all of the work. I'm especially interested in how you removed all of the bushings. I've seen descriptions of the homemade subframe bushing puller/installer. But I'm interested in knowing how hard the trailing arm and diff mount bushings are to replace. Any other info you could provide would be appreciated.

Grace and peace,

Robert K
1991 535i

[Robert K]

I didn't see your reply at first. Just got a new computer and it had me in the default view that didn't show all the posts. Anyway, it sounds do-able. I just know how press fit bushings can be...a total pain. I do understand what you were saying about fabricating the pipe to transfer the load of the press. The last thing you want to do is bend a trailing arm. I'm at the point of making a decision on whether to fix the car and keep it, or just sell it as is. It's still in excellent condition. But I'm figuring I'd have to spend about $1,000 to do all that I wanted. Of course after that, it would nearly be new. Just have to wait and see. Thanks again for the help.

Grace and peace,

Robert K
1991 535i