BMW Z3 - Adjustable Rear subframe camber and toe

[rutger208]

BMW Z3 - Rear subframe camber and toe adjustable

After installing a new shock absorber set (Bilstein B12 Pro in combination with Eibach springs) and old worn rubbers, my Z3 Coupe suffered from camber and especially a lot of toe-out. Up to 10mm toe-out at the rear.

One of the ways to solve this is to make the rear subframe adjustable with, for example, eccentric bolts or with adjustment plates as shown here. Both required welding and slotting.

Bought a used subframe so that I could easily weld on the adjustment plates and slot out the holes. With the new subframe ready and in the POR15 coating, I dismantled the old subframe with a friend. Quite heavy and unconventional, so I would definitely do this with two people.

Immediately replaced the rubbers of the wishbones, subframe and differential. Also reinforced the hanger of the differential due to the possibility of cracking.

Reassemble everything and tighten the adjusting plates by feel. With alignment came to -1.75 degrees camber and 0.5mm toe-in.
Quite a job but happy with the result!

I b

 

[Ryan1B]

Nice, I am doing the exact same thing.

I happen to have the same adjustment kit with the teeth... however, I am not using them now. I did not like the fact that I would have to slot or cut an access hole in the floor for the taller plates ?

so, since I did not want to risk that issue... I opted to also buy the eccentric bolt kit instead from garagistic .

My subframe is out at my nephews this week to get the plates welded on... and then I'll do the dremel slots myself.

I'll do a write on mine when I get it all done. but what I did was remove each piece one at a time instead of all at once and did it all myself. I took the half shafts out one at a time. removed the diff by itself, then removed the trailing arms one at a time. then the final cross member subframe by itself too.

going it this way I was able to handle it all on my own.

Now that is it all out... I'll do new bushings across the board as well.... and a few other surprises I'll wait to post about.

 

[Delk]

Nice, I am doing the exact same thing.

I happen to have the same adjustment kit with the teeth... however, I am not using them now. I did not like the fact that I would have to slot or cut an access hole in the floor for the taller plates ?

so, since I did not want to risk that issue... I opted to also buy the eccentric bolt kit instead from garagistic .

My subframe is out at my nephews this week to get the plates welded on... and then I'll do the dremel slots myself.

I'll do a write on mine when I get it all done. but what I did was remove each piece one at a time instead of all at once and did it all myself. I took the half shafts out one at a time. removed the diff by itself, then removed the trailing arms one at a time. then the final cross member subframe by itself too.

going it this way I was able to handle it all on my own.

Now that is it all out... I'll do new bushings across the board as well.... and a few other surprises I'll wait to post about.

You dont cut the floor. Only thing you need to slot is where the bolts go through the subframe so they can go up and down.

 

[IainP]

If you put it back in a piece at a time, you’ll find you have to shorten one of the bolts. Can’t remember if it’s the inner, or outer, still leaves plenty of thread though.

 

[Ryan1B]

You dont cut the floor. Only thing you need to slot is where the bolts go through the subframe so they can go up and down.

Ah, good to know. I must have read that wrong somewhere... plus I think the eccentric ones will make it easier for adjustment anyways. plus , this car will never see a track or driven hard, so I am not concerned that much. it's a sunday cruiser