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Old 04-13-2012, 07:34 PM
Quick99Si Quick99Si is offline
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Location: Chicago
Join Date: Jul 2011
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Mein Auto: 2004 M3 6MT
Originally Posted by PokerIzWork540 View Post
Ok someone help me out here just created an account to get a little assistance.. Ive just recently bought a 97 540i and just did a shtload of work already cause previous owner was brain dead i suppose. So I just replaced the rotors and pads in the front which ended the vibration at low speeds while braking.. Now after driving today I noticed the strong vibration at 50-60 while often having to over steering to the right while headed str8 (too loose?).. So I jacked the car up and the driver side wheel has a lot of play, not from top and bottom pressure but has lots of play from side to side (a lot of play actually)..

So ive read through this forum and with all the terms upper control, Lower arm, right upper, rear lower, thrust arm, traction strut, wishbone.. and theres actually more ive heard etc.. So when i look under at whats moving I see three main bars all of which are moving a bit under there, so which do I change first.. Is there 1 main arm that will prevent the whole assembly from moving around?? The one thing im clueless on with cars is this crap... thanks in advance for any help!
You need to step back and figure out which is the issue before you proceed. The movement you're describing can be due to any link down there.

Before we proceed, I should clarify the common names for those components..

Two aluminum bars, silver in color:
1. boomerang shaped one, closer to the back, mounted at 45 degrees to the car is the thrust arm. This one should also have a warning stickers about not hooking to it.
2. straight one in thefront, mounted perpendicularly to the car is the control arm, as they call it.

The last link you're seeing is part of the steering system, black in color (not aluminum), and should have some threads exposed. This is the outer tie rod.

The bad news is, they all wear and go bad. The good news is that you can figure out which by wiggling the wheel and looking for freeplay in a few key spots, essentially where the bushings and balljoints sit. This is easier with an assistant, obviously. The thrust arms also last about 60k miles so you may as well replace them anyway.

So take a look at where the freeplay is, then search around how to replace the part (always in pairs) because it isn't exactly straightforward. Popping the balljoints is a bit tricky, as is properly reinstalling the tie rods (count threads), bushings (torque under load), etc. There are a few very good DIYs here for all if those.

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