# e39 540 control arm question



## Sands (Apr 7, 2004)

Getting ready to replace the suspension on a 100k mile e39 540. How do I know if I need to replace the entire control arm or just the rubber bushings?

Will I see any fluid leaking out of the pivot balls? Looseness?

thanks!
Ian


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## DZeckhausen (Mar 11, 2003)

Sands said:


> Getting ready to replace the suspension on a 100k mile e39 540. How do I know if I need to replace the entire control arm or just the rubber bushings?
> 
> Will I see any fluid leaking out of the pivot balls? Looseness?
> 
> ...


I assume you are talking about the front suspension? There are two lower control arms on the 540i front suspension. The shorter, straight arm is called a Wishbone. The longer, curved arm is called a Traction Strut.

The wishbone comes complete with a new ball joint at one end and a new bushing at the other. The traction strut comes with a new ball joint, but requires a separate bushing to be purchased and pressed into the other end. At 100,000 miles, it's probably a good idea to swap them both out. Check Pacific BMW for pricing. I think you'll find those pieces are not as expensive as they look.







*Wishbone*​






*Traction Strut*​


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## Sands (Apr 7, 2004)

DZeckhausen said:


> At 100,000 miles, it's probably a good idea to swap them both out. Check Pacific BMW for pricing. I think you'll find those pieces are not as expensive as they look.


Just what I was looking for. Thanks. Best price so far is on ea4parts.com (spelling?) 119 for the arm and ~95 for the wishbone. Arm is less bushing.

Another question.... I've seen urethane bushings for sale for both. Is the performance improvement worth the extra NVH? I autocross and participate in several track schools a year.

thanks!
Ian


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## DZeckhausen (Mar 11, 2003)

Sands said:


> Another question.... I've seen urethane bushings for sale for both. Is the performance improvement worth the extra NVH? I autocross and participate in several track schools a year.


I would stay away from the urathane bushings. One of the things I like best about the 540i is the ability to gobble up highway miles with nary a squeak or a rattle. I think there are better ways to spend your money on this car. Now, if your plan is to turn this 540i into a dedicated track car, that's another matter entirely!


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## Lscman (Aug 5, 2003)

DZeckhausen said:


> I would stay away from the urathane bushings. One of the things I like best about the 540i is the ability to gobble up highway miles with nary a squeak or a rattle. I think there are better ways to spend your money on this car. Now, if your plan is to turn this 540i into a dedicated track car, that's another matter entirely!


I have yet to see a genuine, dedicated E39 track car. Too many smart folks out there choosing the proper tool (2800 lb Porsche or M3 etc). I'm still hoping to witness a wealthy, stubborn M5 track enthusiast trailering his M5 to the track to duke it out with Subaru's, 944T's and Mustang's. A guy who likes to kill a flea with a $125K highly-modified sledgehammer.....supercharger, 10+" wheels, big brakes, track suspension mandatory. It'd be great dinner discussion, eh?


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## DSPTurtle (Oct 4, 2003)

I have urethane bushing on my traction struts and my sway bars. No noise so far and it really made a huge difference on the traction struts...no shimmy, ever.
JB


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## Sands (Apr 7, 2004)

DSPTurtle said:


> I have urethane bushing on my traction struts and my sway bars. No noise so far and it really made a huge difference on the traction struts...no shimmy, ever.
> JB


How is the road noise?

I've driven in Florida and the roads are suprisingly similar to Iowa's


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## DZeckhausen (Mar 11, 2003)

DSPTurtle said:


> I have urethane bushing on my traction struts and my sway bars. No noise so far and it really made a huge difference on the traction struts...no shimmy, ever.
> JB


Was the huge difference you mention the lack of shimmy? If that's the case, then new factory bushings would have had the same effect. Or did you notice a dramatic improvement in turn-in response?


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## DZeckhausen (Mar 11, 2003)

Lscman said:


> I have yet to see a genuine, dedicated E39 track car. Too many smart folks out there choosing the proper tool (2800 lb Porsche or M3 etc). I'm still hoping to witness a wealthy, stubborn M5 track enthusiast trailering his M5 to the track to duke it out with Subaru's, 944T's and Mustang's. A guy who likes to kill a flea with a $125K highly-modified sledgehammer.....supercharger, 10+" wheels, big brakes, track suspension mandatory. It'd be great dinner discussion, eh?


Aside from the supercharger, MIB on m5board.com, is coming close to this. I wouldn't be surprised if he starts stripping the interior in a couple years! :yikes:


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## Lscman (Aug 5, 2003)

Mib's about as close as they come...but something tells me I'm not going to Australia too soon.  

He's installing a 400lb/in progressive DFC kit that rides like stock & it appears his mods will remain tasteful & practical. I'm looking for a nut with 700lb/in GC's that trailers his car with race rubber, no license plate, custom roll cage, no rear seat & wants to outrun gutted E30 and E36 M3's with the customary 550lb/in GC's....you know, a real fool. Somebody who wants to buy one-off carbon fiber rear passenger doors to drop the weight below 3700 lbs (lol). The 5 series enthusiasts need a hero.


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## Sands (Apr 7, 2004)

Lscman said:


> Mib's about as close as they come...but something tells me I'm not going to Australia too soon.
> 
> He's installing a 400lb/in progressive DFC kit that rides like stock & it appears his mods will remain tasteful & practical. I'm looking for a nut with 700lb/in GC's that trailers his car with race rubber, no license plate, custom roll cage, no rear seat & wants to outrun gutted E30 and E36 M3's with the customary 550lb/in GC's....you know, a real fool. Somebody who wants to buy one-off carbon fiber rear passenger doors to drop the weight below 3700 lbs (lol). The 5 series enthusiasts need a hero.


Want to sponsor me? LOL :rofl:


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## Lscman (Aug 5, 2003)

I'm looking for some fool who spent his own money trying to turn an overweight luxury saloon into a dedicated track car. It reminds me too much of my old friends...Lincoln Mark VII owners who flush coin & butcher nice vehicles, trying to turn their 3800lb coupe into a 3200lb Mustang. It's fun to watch them take a coal shovel to the interior to try getting under 3500 lbs. I can admit my Mark VII has seen plenty of track, but for the record, it still has stock gearing, automatic and it remains near 3800lbs.

Honestly...I want to laugh & point at it, not sponsor it.


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