used rotary slide bearings

[delorean175]

Hey guys!

I didn't think this quite needed its own thread in the tech talk section. I did do some research and didn't find much. Anyway, I have an early production e28 with the rear subframe that doesn't have the pitman arms. I'm doing an overhaul on the rear suspension because its all original. I have a subframe from a later car that does require them. I also have some (braced) rear trailing arms from an e32 that uses the rotary slide bearings. Apparently they are the same trailing arms used in the m5. When the bearings are cleaned and greased up they feel like they have a very small amount of wiggle in them. I bolted them to the subframe as a mock up to see if I felt any play, nothing. But I understand they might feel tight on the garage floor but under the stresses of driving they could be completely sloppy. Does anyone have any experience with these bearings? I might go with poly trailing arm bushings if these are worn out, because replacement rotary slide bearings are pretty expensive. Any insight would be greatly appreciated!

[Cactus]

I have never successfully removed these bushings. I haven't found a good way to stick them in a press. They seemed tight, so I just slapped them back on a car. I would prefer to use 2 piece poly bushings just for ease of install.

[ElGuappo]

I installed the full trailing arm from an E32 740 onto my E23.
The trailing arm is the same part as all late E28 and E32/34.
The differences start with the flanges, inner and outer are different and pose different problems.
If you have a non ABS car then you are actually in luck, as the E32 inner flanges have the wrong tone ring to work with E28 ABS.
The output flange has different stack heights and change effective offset depending which one you use: E32 output shaft pushes the wheel 8mm closer to the fender.
I personally LOVED how the bearings felt, any wiggle the trailing arms had before was gone, now they only move in the up/down arc they are supposed to go.

[delorean175]

Thanks for the replies guys!

If its that much of a pain in the ass to change out these rotary slide bearings think I will just run them the way they are first and see how it goes. One way you could remove them is by popping out the metal center sleeve and (carefully) sawzall through the outer sleeve. Then try to press it out. That was how I managed to get out the factory subframe bushings.

I installed the full trailing arm from an E32 740 onto my E23.
The trailing arm is the same part as all late E28 and E32/34.
The differences start with the flanges, inner and outer are different and pose different problems.
If you have a non ABS car then you are actually in luck, as the E32 inner flanges have the wrong tone ring to work with E28 ABS.
The output flange has different stack heights and change effective offset depending which one you use: E32 output shaft pushes the wheel 8mm closer to the fender.
I personally LOVED how the bearings felt, any wiggle the trailing arms had before was gone, now they only move in the up/down arc they are supposed to go.

I have a non ABS car, but I wanted to have the option to install an ABS unit I picked up a set of e28 inner flanges with the ABS rings. iirc I also have the outer e28 flanges also. I didn't want to mess with pulling them off my existing trailing arms.

I have never successfully removed these bushings. I haven't found a good way to stick them in a press. They seemed tight, so I just slapped them back on a car. I would prefer to use 2 piece poly bushings just for ease of install.

I have a set of the subframe bushings from Powerflex. They were super easy to install. However I did get an audible squeak sound from them after a while. I ended up pulling them out and covering them in an anti-cease paste then reinstalled them. Its been quiet since.

[ElGuappo]

It is so much easier to R&R the entire trailing arm I don't understand why you would consider just doing the bushings/bearings?
To press them out you've already done half the work to remove the bolts and have the trailing arm hanging there.
Just remove the shock mounting bolts and the drive axle bolts, brake caliper, and of course the parking brake cable.

[delorean175]

It is so much easier to R&R the entire trailing arm I don't understand why you would consider just doing the bushings/bearings?
To press them out you've already done half the work to remove the bolts and have the trailing arm hanging there.
Just remove the shock mounting bolts and the drive axle bolts, brake caliper, and of course the parking brake cable.

Pretty much all there is to R&R on the trailing arm is the wheel bearing, Rotary slide bearings and pitman arms right? Also sway bar links. The rotary slide bearings were the only thing I was unsure about. I think I will try running them the way they are because of cost. The trailing arms are currently stripped (except for the rotary bearings) awaiting new wheel bearings and flanges.

[ElGuappo]

I think we are both talking about the same thing from 2 different angles.
You have stripped the E32 trailing arms and are installing new wheel bearings and assorted bushings.
That is the logical course of action, just be aware of the offset +8mm using the E32 flanges introduce.