Aproximate cost of rear subframe swap?

[Marvin_Hecht]

Hi -- My own car has rusty trailing arms, and I have a parts car with a clean rear subframe. One of my rear bearings is bad, and it needs to be replaced, so I thought the time is right to swap the whole subframe. I'd have new trailing arm bushings put in, and also new "coke can" subframe bushings put in. I might even have a 3.46 LSD diff put in. Assuming I have the parts (I'd have my parts car towed to the shop for extraction and gutting), what would the approximate cost be for a mechanic to do this all, say at an independent BMW shop?

I am just learning and while I can do rear shocks, the whole subframe thing scares me. Another thought I had was to just replace the traling arms themselves one-at-a-time at my house, but even then it looks like I would have to mess with the brakes, parking brake, lots of touch bolts, etc.

Thks in advance.

[StereoInstaller1]

Marvin, do not be afraid. It is a parts car, right? SO go to Harbor Freight, but some "Dollies" so you can move the thing when you are done.

Remove the E-brake cables from the handle, adn start removing bolts!

E30's are so easy to work on, you will end up victorius.

At the very least, by yanking your old subframe, you will know more of what you can do.

Luke

[808BMW]

Yank the whole subframe, it's not that hard. It is however VERY heavy (subframe, diff, trailing arms, brakes, all one big thing) so be careful.

[Marvin_Hecht]

Now to unconnect the subframe though, don't you need to remove those coke-can shaped subframe support bearings, and to get them out, you practically need a blow-torch?

Also the Bentley discusses how one may need special tools to do this, in particular when dealing with the CV joints. However I guess if you are going to take the whole thing down with Diff, you just need to unbolt?

And would jackstands in the rear (on the long beams that go the length of the car) be sufficient to keep the rear off the ground while working?

[StereoInstaller1]

Now to unconnect the subframe though, don't you need to remove those coke-can shaped subframe support bearings, and to get them out, you practically need a blow-torch?

I used a BFH, was pretty easy. Don't forget the diffy!

Also the Bentley discusses how one may need special tools to do this, in particular when dealing with the CV joints. However I guess if you are going to take the whole thing down with Diff, you just need to unbolt?

Nah...leave the driveshafts in. It is kind of heavy. Be prepared.

And would jackstands in the rear (on the long beams that go the length of the car) be sufficient to keep the rear off the ground while working?

They were for me.

Luke

[Marvin_Hecht]

Is it true that to unbolt the subframe, it is only 3 bolts? The big bolt holding the differential, and the 2 bolts that screw the subframe onto the coke-bottle shaped rear subframe bushings?

Also my parts car is ABS but my own car is not - what additional complications would this impose?

Thanks Marvin.

[matte30is]

I just did my subframe and put inthe IE poly bushings. It sucked. My old bushings were corroded and didnt come off the studs that hang from the car. I finally broke them loose and ended up breaking off the shaft that recesses in the frame (1/2) inch or so. So them I had to shave off the shaft on my new bushings just to put it back together.


With old cars and corrosion nothing is easy to do on these cars. Be prepared.

[Mike B.]

So them I had to shave off the shaft on my new bushings just to put it back together.

Not a good idea!

If you run into this problem of having the aluminum shafts breaking off in the body (which is fairly common), drill some holes in the remaining aluminum, then use an air hammer with a pointed chisel to break the pieces up and they will fall right out.