Xoutpost.com - New thrust arm bushings still no help

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Quote:

Originally Posted by bcredliner (Post 942416)

I have never torqued in the air so I don't know how big a mistake that is. How many miles do you think would have to be driven those two months?

Oopsi, Meant I have always torqued in the air to be sure not to over stress the bushing and it says to do that in the manual. don't know how many miles it takes to destroy the bushings. What's the estimate?

Quote:

Originally Posted by davintosh (Post 942429)

http://www.autohausaz.com/secure/Par...1121096372.jpg

That's one of the thrust arm bushings. The bolt that goes through the center and holds it to the frame also keeps that center metal insert in a fixed position; it doesn't rotate. The metal ring on the outside of the bushing is bound tightly to the thrust arm, and rotates with the up/down movement of the thrust arm as the vehicle moves over obstacles. The rubber connecting the center to the outside ring is designed to flex a bit, and allows up/down movement within a given range.

BUT... If the center of the thrust arm is torqued down without first loading the front suspension, the center starts out rotated down. When the vehicle is lowered to the ground and the weight of the vehicle is on that corner, the rubber will already be stretched almost to its designed limit. Thinking about that it's easy to see how the bushing will fail pretty rapidly.

One alternative I'm looking into is using spherical bearings instead of bushings. They are pretty widely used on other vehicles, especially offroad vehicles; one of the guys on the mye28.com developed a set for the e24, e28, e32 & e34, and has pretty good success with them. They do transmit a bit more road noise to the frame and cabin than OE bushings, but their longevity is much improved over OE, and replacing the wear parts is far easier than replacing the entire bushing. They also have a lot less flex than OE, so steering response is far improved as well. Since they are a spherical bearing instead of a rubber bushing, they don't require the suspension to be loaded before torquing down the center bolt.

Right now he's working on a variant that would fit the e53, which should also fit the e39 and a couple of other models. I'm thinking the pricing would be similar.

Moosehead Engineering Spherical Upper Control Arm Bushings

http://images.ecwid.com/images/525075/15262624.jpg

any news on progress of these bearings for the X5? website doesn't list it yet.

I got an email from Paul at the end of August, and it sounds like he is getting close to having test pieces, but I haven't heard anything since. He's looking to verify the outside diameter of the e53 bushing; I put a cheapo plastic caliper on mine and it was about 2 5/8", but I'm not terribly confident in that number because of corrosion on the bushing and my measuring instrument. Paul says the e38 bushing is 66mm (2.59843"), which is in the ballpark of what I got. If anybody has a new bushing that they could put a caliper on, that would be immensely helpful.

Isn't it true that the E38, E39 and E53 all can share the same thrust arm bushing?

I remember on the M5 forums that people were using the X5 bushings before polyurethane ones came out.

I just ordered the Powerflex set. I can measure those next week...now if Paul needs a beta tester, I could wait to install the PF bushings... :)

FYI, E38/E39/E53 same size bushings, but different construction. See this thread on M5 forum.
X5 Thrust arm bushings - BMW M5 Forum and M6 Forums