[satz]

Hi all

please see image. Is this called the ball-joint boot?

I recently replaced the suspension, and it looks like I might have split these, though I don't know how.

And is there a DIY to replace just that part?

thank you

Perfect excuse to upgrade to M3 parts here

[satz]

so the dealer (who pointed this out during my wheel alignment), said that the entire lower control arm has to be replaced (31122405859). You apparently can't just replace that rubber bushing

[juld0zer]

That would be correct, as through BMW you cannot buy the balljoints or boots. Just the arms and fasteners.

Once the boot is torn you cannot rule out the possibility of water and dirt ingress causing issues down the track. The most cost effective solution would be an OE replacement from Lemforder or TRW, etc. Replace all fasteners involved, and the inner bushing bolt must be tightened with vehicle at ride height.

[feuer]

The most cost effective way is get a used part on the cheap and reuse the boot only (if your control arm is newer and in Ok condition)

[avocet]

Originally Posted by satz

I recently replaced the suspension...

So the arm is basically new? I would do what feuer says unless that boot is bonded on in such a way that it is not reusable.

If so, that tear looks quite small. I would inspect the boot and see if there has been any grease wash out or contamination. If it looks like it is still healthy in there I would then consider finding a good flexible sealant like high strength silicone or something like this:

http://flamemaster.com/cs-3204-class-a-b-c



Sure it might look a little... rough. But since you know it is in decent shape, and it will let you know if you keep an eye on it if it begins to wear prematurely.

[Efthreeoh]

Just get a new control arm. There is no fix for a torn boot. Also, once the boot is torn, the ball joint is compromised and will eventually wear out. Losing that ball joint is very dangerous because it locates the hub (wheel and tire), so if it separates you will lose control of the car. The part is around $100.

[satz]

hi avocet, the arm is the original non-M-sport arm.
The only suspension parts I replaced were the springs and shocks, but didn't touch anything else

cheers

[mweisdorfer]

I'd upgrade to the M3 control arms and redo the tie rods while your in there.

http://www.e90post.com/forums/showthread.php?t=788761