Quote Originally Posted by 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
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