Trailing Arm -- Ball Joint Upgrade (from rubber bushes)

[RocketyMan]

I decided to upgrade the rubber bushings in the rear trailing arm to FCP-modified ball joints.

A little background:
I started to get really annoyed with going over smooth road and getting really bad bump-steer in the rear axle when going over man-holes and such. FCP had these ball joint upgrades and I was very interested since there is little to no deflection with a ball joint vs rubber bushing.
As an FYI, these seem to go out of stock every once in a while. (I got them on sale last )
https://www.fcpeuro.com/products/bmw...-33326763092sm

Figuring out how to do this, there was no great walkthru. PelicanParts had a only half-baked walkthru that I wasn't at all impressed with:
https://www.pelicanparts.com/BMW/tec...eplacement.htm

Hence my endeavor.
As for tools, I would suggest having a few key items. It is very nice having little extra tid bits around to use as a driver, spacer, etc. Needless to say, I had to do a bit of scrounging in my garage to find something that would work.

Special Tools:
1. Autozone rent-a-tool balljoint remover: Part #57023
https://www.autozone.com/test-scan-a...set/557231_0_0

2. M12X180mm bolt class 8.8 (I wish there was a 10.8..but nothing) -- I went down to local hardware store to pick this up
3. M12 flanged-nut that is hardened as well as five hardened washers (unfortunately I couldn't find a fine-thread setup)

4. A non-deep 12 pt 1-1/4 socket (1/2" drive so the m12 can fit through)

5. EP lithium grease to grease the threads of the M12 setup. This is going to need plenty of it to try and preserve the threads as long as possible. Then also some PB blaster or penetrating oil.

[RocketyMan]

My plan was to try and do this WITHOUT having to drop the rear axle carrier and/or moving the fuel tank out of the way.

DO NOTE:
When working with the threads on the carrier, pay attention to any threads before they contact the fuel tank. Having about 5 of the hardened M12 washers helps with precise positioning.
Also, the axle carrier brake line bracket can somewhat interfere with your setup. I have steel braided lines, which didn't hurt them at all...but it did rub a bit.

Take you time with this. It was a bit frustrating for me at times--but it just amounted to getting creative with my setup and the sequencing of various spacers/washers, etc.

Once the rubber bushing is removed, it's a good idea to clean up the pocket and lube it with the EP grease you have to prevent any binding. A good hint when removing the bushing is you'll bind up the aluminum outer shell of the bushing and hear it *pop* when it removes. Aluminum loves to gall. So use some spray lube.

Then take you upgraded ball joint and lube that outer shell with the grease as well. This will again help with preventing any binding. It's crucial to try and get the ball joint as perfectly square to the surface to go in smoother. Once it's in, try and center it where both sides stick out equally.

[RocketyMan]

I didn't get lucky getting every single bushing out in tact. Most of the time using the 1-1/4" socket just pushed out the inner bush. Ohwell...tapping the outer shell of the bush out wasn't too hard. Again, just be creative if this happens, try and get the socket out. Then you can fold in the out shell of the remaining bush and it comes out seamlessly.

DO NOTE:
It really helps to gain a bunch of clearance by removing the rotor, parking brake shoes, and then loosening the disc shield. It can rotate about the rear hub so that you can get the clearance to get all the adapters and such on and not be in the way of the brake shield. It's only four 10mm bolts holding it on.

I know this might be a little silly, but I had a huge 1-3/4" wrench that actually ended up making pressing the new ball joint into the receiver more "square." Again, once you press it through, make sure this is even in the receiver on both sides.

Once you get all four ball joints installed, button everything else back up. Notice that the trailing arm is free to articulate--but solid with no movement radially.


P.S. I ended up eventually rolling the threads on the M12 bolt. If it was a class 10.8, it would've def lasted much longer. But a $5 bolt sure beats spending on the bav-auto toolset. Oh...don't forget to return the Autozone rent-a-tool.