Front Control Arm Bushings - the dreaded wobble

[Bmwstylz]

i have the typical wobble under braking in steering wheel. mostly 100km down to 80km... car fairly smooth at other speeds during braking. no real vibration in brake pedal.

i'm pretty sure its the FCABs. I want to do just the bushings not complete control arms. The repair looks pretty straightforward on pelican parts.

has anybody done this themselves? easy to hammer off or do I really need to start cutting?

[DET1990]

You can use a 3 jaw puller to pull it off the control arm when ive done it i cut the outer part off then use the puller on the remaining piece of rubber install is kinda tough with the stock bushings but can be done

[cirrusblau]

I managed to get new Meyle HD bushings on by hand with just some dishsoap, working under the car. The hardest part was getting it started. Once it was on, it slid home with (relative) ease.

+1 on the 3 jaw to get it off.

[rmanaudio]

FCAB are really easy to replace M or non-m. Just hold the old ones off and put some WD-40 between the groves and pull or hammer it out. When installing the news ones use liquid dish soup and gently hammer it back on and bolt it up.

I doubt it will solve your issue. Usually vibrations under braking is caused by either warped rotors or rim or tire issues.

[cirrusblau]

When my FL CAB failed (well, when I bought the car with a bad one), I needed to do a minor steering adjustment when I hit the brakes to counteract the extra angle on the FL wheel.

There was never any vibration like what is typical of bad ball joints.

To the OP, raise the front of the car and with the steering wheel locked and for each of the front wheels, grab them at 3 and 9 and wiggle. If it wiggles, good chance it's your CAB.

[Bmwstylz]

good tips indeed.. yeah I don't want to replace them for no reason. maybe it is the rotors?

i will try the wiggle test first

[jabela]

It's highly unlikely that your rotors are warped. I've never heard of one BMW with actually warped OEM rotors. Maybe your 318ti came with shitty chinese rotors or something. More likely is uneven pad deposits or rusty rotors. Bedding your brakes in usually fixes that.

If you've never replaced your FCABs, they are likely shot. How many KMs on the 318ti?
You can also check by having someone drive slowly and hitting the brakes while watching from the the side. If you see the wheel move relative to the car body then your FCABs are shot.

I used a 2 jaw puller (3 jaw is better) to pull the FCAB off the arm. I replaced them with Powerflex Urethane bushings. I'm pretty happy with them. What's nice is that they're the whole assembly, so you don't have to tear out the old bushing and press in the new ones.
Check your size especially with your oddball 318ti.

http://store.bimmerworld.com/powerfl...hing-p281.aspx

http://youtu.be/PuXbK-g_zfM
http://youtu.be/1pJYBjXk8YE

[rmanaudio]

If you put on your RIMs the wrong way, you can warp your rotors. Rotors can warp on any car. If you have a box setup, move your rear tires to the front and test.

[jabela]

Originally Posted by rmanaudio

If you put on your RIMs the wrong way, you can warp your rotors. Rotors can warp on any car. If you have a box setup, move your rear tires to the front and test.

What do you mean the wrong way?

If there's not a clean surface between the wheel and rotor that can cause vibrations, though that would most likely happen at all times and not just under braking.

Bad alignment can also cause lots of issues. Always good to check that and mandatory after replacing FCABs.

[cirrusblau]

An alignment may be a good idea after FCABs, but I wouldn't say mandatory. So long as the car was aligned while they were good, I don't believe the minor variance from one set of FCABs to the other would cause much difference.

If the alignment was done with bad bushings (which I believe any reputable shop would advise against), then could have all sorts fun front end geometry after FCAB replacement haha

[blk3]

I had the same symptoms as you with my car. It was the bushings that caused it. If you had warped rotors you would have the shake under braking at pretty much all speeds. I got some poly bushings and haven't changed them since

[Bmwstylz]

Originally Posted by blk3

I had the same symptoms as you with my car. It was the bushings that caused it. If you had warped rotors you would have the shake under braking at pretty much all speeds. I got some poly bushings and haven't changed them since

that's exactly what I thought. the brakes are smooth at all speeds with no pedal pulsation.

on the flip side I had a 320i e46 with horrible wheel vibrations and a new set of rotors transformed the car !

[Bmwstylz]

So I finally did the wiggle test with hands at 9 and 3 position. The wheel makes a clicking noise back and forth and comes out maybe 5mm? each way.

I can see the FCAB and it doesn't really move at all.

But the whole wheel and brake rotor wiggle together and 'click' as I push each hand.

I'm thinking now it must be the wheel bearing that needs replacement? There is no noise from it on this side of the car (but oddly enough the other side is slightly noisy at speed and under load (while cornering).

Could a worn wheel bearing produce vibration in the steering wheel under high speed braking?

[cirrusblau]

Are you sure you're looking at the bushing (and not the carrier) of the FCAB? 5 mm is a lot of movement for just a wheel bearing. I'd say that if your wheel and brake rotor wiggle relative to the caliper, then you've got a bad bearing.

Noisy under cornering one way is generally a sign you've got a bad bearing.

And yes, a wheel bearing with that much play would no doubt cause vibration under high speed braking. Better change the bearing before the wheel falls off :p

[Bmwstylz]

yah i was looking at where the metal control arm goes into the bushing. it was hardly moving at all even under heavy shaking of the wheel.

hmm yah i better get those wheel bearings done methings