ufcrusher

So we brought our BMW in for its regular scheduled service appointment and then received a rather confusing call from the dealership.

The dealership informed us that the front control arm bushings, rear trailing arm bushings, and leaking oil filter housing.

Anyone have any idea what these bushings are nor how they could have been damaged. The car didnt feel like there was anything wrong with it, so we are a bit confused.

Help please?

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babymike

i am by no means a mechanic, but my best guess is that since bushing are usually rubber, they may be old and cracked, hence not performing correctly. i'm sure someone will correct me, but that's my best guess.

Nanotech9

yup yup - but unless you've been driving in a ton of salt, they shouldnt go bad within the first 100k miles.

basically, the control arm bushings act as a rubber buffer between the control arm and the frame of the car. The arm pivots one direction within these bushings when the suspension and arm travel up and down.

the trailing arm bushings are basically the same thing - except on the rear of the car. They're between the trailing arm and the frame of the car, again, made of rubber, and reduce road vibrations.

After high mileage or extreme conditions, these bushings will either dry-rot and crack, or sometimes simply wear down and hollow out. If they get soaked in oil too much, the oil will impregnate the rubber, weaken it, cause it to expand, and it will loose its shape and rigidity and sometimes even pop out of its place.

I replaced these bushings in my '91 318is with URETHANE offset bushings (uhh, the offset bushings are from the M3). They transfer a bit more of the road vibrations, noise, and make bumps a bit harsher, but at the same time, stiffen up the handling a bit, and SHOULD never wear out (not for a LONG time at least as they're basically a solid instead of a rubber).

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Nanotech9

In the above image (if its there)...
(1) (purple) is a control arm bushing.
- The control arm is that "L" shapped part that goes out to the wheel. the black dot in the bend of the "L" is a balljoint.

(2) is a sway bar bushing (where it attaches to the frame).

(5) Bushings on either side of the trailing arm.

(6) rear sway bar bushings.

Basically, they're the main pivot points for the suspension on the car. Everytime you go over a bump, theres metal-to-rubber-to-metal rubbing, and after time, it wears out.

look_ma

If you did not meet nano's criterial for needs new ones, go to the dealer and make them show you why.

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mechmike0034

Nano did a great job - excellent diagram and explanation!

http://www.gotapex.com/forums/showth...threadid=70692 (Rear trailing arm suspension bushings.)

I'll give/paraphrase the same advice:

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rasetsu

You just encountered a very typical "lets rape this guy for as much as we can because he trusted us to do a routine service on his BMW" call from the dealer. How old is your BMW? If it's less than 10 years and you don't tear it up on the race track once a week, I highly doubt any of this stuff really needs to be replaced. For the oil filter housing, what they deemed to be a "leak" could be spilled oil from the oil change, stripped threads from the dealer twisting the filter on, or a bad oil filter gasket. If the bushings are bad, the car will probably squeak a lot over speed bumps. Take it to an independent mechanic and let them take a look before giving more of your hard earned money to the stealership. The bushings alone aren't expensive, but the labor to replace them likely will be.

djradam

is anyone a mechanic here? cause i might want to PM ya

ufcrusher

Its a 98 323ic with 71k on it...so in reality relatively low miles, but the history on the car is that it was originally bought in Texas and then out here in San Diego. Thus, it has always been in more arid conditions.

My fiance finally got a service advisor who knew what these things were and could explain them. He told her that we did not need to worry about it. It does not present a safety hazard and he didnt think that it will ever present one. Apparently the only thing that could happen is excessive tire wear.


So is the best bet to order some of these urethane bushings and taking it to a non dealer bmw service provider and getting them changed out or just sitting on it?

mechmike0034

Call this guy, tell him Mike from iATN referred you, and get him to take a look. His bread and butter is Asian imports, but he may be able to either offer you a second opinion or recommend a good independent BMW shop...

rasetsu

I would worry more about the oil leak (if there really is one) than the bushings. Keep an eye to see if any oil is dripping down and check the oil level about once a week. When the bushings really need to be replaced, I would stick with the rubber ones as opposed to urethane if the car is not used for competition purposes. These things really shouldn't need to be replaced and when they do, have an independent mechanic do it.

Nanotech9

i agree - dont use urethane bushings unless you plan on taking the car to teh track every weekend.


djradam - i'm no mechanic, but i can do some things myself. Usually the only things i know are things i've tried to do myself.

like for example, right now i've got the motor out of my BMW. Yeah, i had a couple of mechanic friends over to do most of the work, but they made me help out and get involved. As of 1 months ago i wouldnt have ever considered pulling out my radiator. Not only did i pull the radiator, but also the intake and exhaust manifolds, and I pulled the tranny off the motor. The other guys actually decided how to lift the motor out and where to attach to it etc, but i was right there helping manuever it.

my two mechanic buddies, my car, my garage... and my motor and my stress level suspended from the ceiling



anyway - ask away on your questions. I probably cant answer many of them, but maybe i can help out a little.

Airencracken

Yikes!

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TERRIBLETOM

You know, this is typical of a dealership, they figure no one will question them. I perform all the suspension overhalls and frame straitening for our body shop and I cannot recall one instance of any bushing being defective unless the vehicle was over 10-15 years old. Of course this is just my observation.