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-   -   Still twitchin'...........! (http://forum.e46fanatics.com/showthread.php?t=797932)

CERF04ZHP 10-13-2010 11:30 AM

Still twitchin'...........!
 
What's up fellas.

Looking for some advise...

I have a 2004 330i sedan and had developed a quick twitch in the steering wheel when I stabbed the brake pedal, which is a tell-tale sign that the front CAB's were getting tired. Well, I replaced them with OEM CAB's and although it's better, if I get on the brakes quickly, it still twiches upon initial contact. Gradual application of the brakes lends no steering wheel play, but if I have to quickly go from gas to brake, when I hit the brake pedal, the steering wheel twitches for a split second right when I grab the brakes.

I understand the CAB's are designed to have some play, to take stress off of other suspension components, but I don't think it's suppose to twitch in my hand when I get on the brakes.

I have had my front end evaluated for anything else that may be fatigued or loose that would give me that sort of sympton, but everything is nice and tight.

My question is this: If I replace my CAB's with a press-in Urethane unit from Bavarian Autosport or Turner, will that eliminate my twitch? Or do you think the OEM units I replaced them with are bad? Or any other advice/experience for me?

Thanks!

TxZHP04 10-13-2010 03:56 PM

Have you verfied that the contral arms were inserted to the exact same depth into the new CABs on both sides? An asymmetry could result in a twitch like this. How much front camber are you currently aligned to?

CERF04ZHP 10-13-2010 04:29 PM

I have not verified the depth. Camber should be exact to whatever the factory specs. are. How could I tell if the control arms were too shallow or deep into the bushings?

TxZHP04 10-13-2010 05:16 PM

I believe the Bentley manual lists a spec for the insertion depth but the real question is whether it's the same on both sides. You might also check to see if you are getting even brake pad wear on the left and right wheels. I would normally suggest checking the control arm ball joints as well but you've already indicated that the usual suspects have been inspected.

CERF04ZHP 10-13-2010 05:30 PM

Right. I will check Bentley's for depth and re-evaluate. If for some reason I am not getting even wear on the brake pads on one side, what would that indicate? That one of the calipers is hanging up? Have you replaced your CAB's on your ZHP yet?

cooler20b 10-15-2010 10:03 AM

Check ur brake rotors a slightly warpped rotor will twitch the same....

WFRFitness 10-15-2010 10:11 AM

Quote:

Originally Posted by cooler20b (Post 12351884)
Check ur brake rotors a slightly warpped rotor will twitch the same....


+1 can't believe this wasn't your first thing to fix / replace. :thumbsup:

TxZHP04 10-15-2010 10:50 AM

Rotors don't warp but they can develop uneven pad deposits. Typically when this happens though, you will get a vibration through the steering wheel when braking. I believe the OP is only experiencing a single abrupt change in steering angle upon initial application of the brakes as opposed to a more lengthy vibration so this is not likely to be his problem.

WFRFitness 10-15-2010 12:49 PM

if it's a single abrupt change and it's always in the same direction then it's a caliper problem... no matter how stiff your FCAB's are if you have a caliper in the front which isn't working properly the car will pull hard to the side of caliper which is working. The 'tell tale' sign that the FCABs are going bad is twitching when hitting bumps and it twitches back and forth not just in one direction.

If the car is making a sudden pull or twitch to one direction when hitting the brakes and that direction is the same every time than you have a caliper problem.

Lesson #1 is diagnosis... if the problem shows itself when performing a specific task (in this case braking) than the problem is most likely within the system involved in performing that task (in this case brakes)

hummer 10-18-2010 11:02 AM

Any unbalance side to side can cause twitching. Say one bad strut for example.

CodeName_88 10-18-2010 02:17 PM

I replaced my control arms and FCABs and still had the same issue - replaced my struts and it was all good.

Make sure to get an alignment as well.

mvrk10256 10-18-2010 02:20 PM

2 Attachment(s)
make sure they were pressed in correctly or it can seriously **** you up. cause the inners will fly out on the road. ask me how i know...... :facepalm:

this is one side
http://forum.e46fanatics.com/attachm...1&d=1287429597


the heatshield saved my ass on the other side

http://forum.e46fanatics.com/attachm...1&d=1287429597

TxZHP04 10-18-2010 02:27 PM

Quote:

Originally Posted by mvrk10256 (Post 12361543)
make sure they were pressed in correctly or it can seriously **** you up. cause the inners will fly out on the road. ask me how i know...... :facepalm:

Just to clarify, this particular issue is only a problem with certain poly CABs.

jb1 11-02-2010 10:04 AM

I have this EXACT same issue with me 2005 330vert. I had the BMW dealer replace the CAB's and I still get the twitch when you hit the brakes with a quick light tap. I had them go over it again twice and they tell me that everything looks tight. They even re greased the slides on the front calipers. It also just had a 4 wheel alignment. The only other thing I can think of is that the brakes need to be bled or something. He even went to the extent of measuring my rotors on both sides to make sure they were wearing evenly. Very frustrating. I had a 2002 coupe that I don't remember it having this issue.

Shalaylea 11-04-2010 03:52 PM

I have a 2005 ZHP with the exact same issue. I finally gave up on trying to fix it. It gets better with new CAB, tires and/or alignment but has never completely gone away. I had a dealer brake bleed and dealer replaced the brakes under the new car warrantee. When I first posted this issue a few years ago, there seemed to be fewer people who had experienced it, there's good info here now, but sadly, you may be SOL.

CERF04ZHP 12-27-2010 04:14 PM

I am going to have the brakes bled, and while they're in there, check the rest of the brakes out for wear patterns and uniformity, etc. Down the road I will replace the struts, but right now I'll just deal with it.
The weird part, is that when it's really cold out (like under 20 degrees), the twitch isn't there! But as soon as it warms up again, it comes right back! I hate these kinds of annoying little problems that don't have definitive answers!

Blocked Out 12-27-2010 09:51 PM

Quote:

Originally Posted by CERF04ZHP (Post 12343747)
What's up fellas.

Looking for some advise...

I have a 2004 330i sedan and had developed a quick twitch in the steering wheel when I stabbed the brake pedal, which is a tell-tale sign that the front CAB's were getting tired. Well, I replaced them with OEM CAB's and although it's better, if I get on the brakes quickly, it still twiches upon initial contact. Gradual application of the brakes lends no steering wheel play, but if I have to quickly go from gas to brake, when I hit the brake pedal, the steering wheel twitches for a split second right when I grab the brakes.

I understand the CAB's are designed to have some play, to take stress off of other suspension components, but I don't think it's suppose to twitch in my hand when I get on the brakes.

I have had my front end evaluated for anything else that may be fatigued or loose that would give me that sort of sympton, but everything is nice and tight.

My question is this: If I replace my CAB's with a press-in Urethane unit from Bavarian Autosport or Turner, will that eliminate my twitch? Or do you think the OEM units I replaced them with are bad? Or any other advice/experience for me?

Thanks!

You should give the new CABs a few weeks to settle in. And if the twitch still continues to bother you, you might to want to check things like your strut tower hats, tie rods for play/wear.

You can switch to Polyurethane bushings at any given moment, and yes, they will get rid of ALL steering wheel play (given there are no other worn out components that need to be addressed).


My recommendation is Powerflex, keep in mind that Polyurethane bushings will transmit more vibration and road feel in to the steering wheel and some people have found them unbearable(there are also people who want to raise their car from a stock suspension height, because they think its too low, as they are used to driving minivans all their life, but thats another story... ), I for one have Powerflex CABs and absolutely love them.


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