I still need help with my front brakes issue, new rottors

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Anri
Posts: 137
Joined: Thu Mar 08, 2007 4:08 pm
Location: Los Angeles, California

I still need help with my front brakes issue, new rottors

Post by Anri »

I just changed the front Rotors with brand new Zimmeran and the problem is still there ! ! !

I am so pissed of that cant find the prblem.

The ball joints are good they dont play, the shoks are new Bilstein HD, I just changed the bushing on the control arm with new (I thought thats why its shaking).

The simptom is: say from 65/70mph you press the brake on light way foot and you hold the same press and the car is going down from 55mph to 50mph and the steering wheel start shaking like crazy, the same time I dont feel the brake pedal to shake so its not the rotors as I just said they are brand new installed!

WHAT ELSE COULD BE I NEED HELP PLEASE

Reagrds
Anri
Shark6er

Post by Shark6er »

its your control arms or your calipers need rebuilt
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Brucey
6 Series Guru
6 Series Guru
Posts: 10077
Joined: Fri Apr 09, 2004 7:17 am
Location: Cambridge, UK

Post by Brucey »

it could also be runout-induced disc thickness variation; this can afflict rotors at very low mileages.

If the running clearance between pad and disc is too small (sticky calipers, master cylinder fault etc etc) then this will turn a small run-out (in which the disc kisses the pads) into a thickness variation pretty quickly.

If the runout is bad (eg dirt on the disc mounting flanges) then even a normal pad to disc running clearance can cause DTV.

The tolerance for disc thickness variation is so tiny you can't really measure it.

I have had an intermitten DTV problem for some months, caused by a master cylinder fault that intermittently causes the brakes to drag.

When the brakes are OK, a couple of hard stops from 120mph down to 70mph (brutal I know) usually sorts out any DTV by dressing the disc surface after that braking is fine from any speed. With brakes bad or since a bad episode with the brakes, braking is very poor at 55-60mph as you describe. All this with new TCA bushings, good ball joints etc, too.

hth

cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
EMMMM_90

Brakes shaking

Post by EMMMM_90 »

Hey Guys I have not been on here much as I have been on the market for a new job. Seems like its finally over and start next week. I have a one week vacation so you will definitely see more of my presence here on the boards.

... Any how back to these brake issues. Brucey has many good points. However on cars this old I would if wallet allows change some if not all of the components that might be associated with the steering. Ball joints, Bushings, brakes rotors, ect ect. I have encountered that if the previous owner neglected to fix the original problem then most likely the problem created a domino effect damaging other parts associated with the original problem. Thus one fix requiring another fix and so on and so forth.

In the long run if most parts are replaced they will last a long time but if not perhaps the problem will reappear once parts that were not change begin to show wear during driving.

My 2Cents.
donudel

Re: I still need help with my front brakes issue, new rottor

Post by donudel »

Anriart wrote:I just changed the front Rotors with brand new Zimmeran and the problem is still there ! ! !

I am so pissed of that cant find the prblem.

The ball joints are good they dont play, the shoks are new Bilstein HD, I just changed the bushing on the control arm with new (I thought thats why its shaking).

The simptom is: say from 65/70mph you press the brake on light way foot and you hold the same press and the car is going down from 55mph to 50mph and the steering wheel start shaking like crazy, the same time I dont feel the brake pedal to shake so its not the rotors as I just said they are brand new installed!

WHAT ELSE COULD BE I NEED HELP PLEASE

Reagrds
Anri
So many things to check.

When you changed the rotors, did you use new pads? If so, did you bed them in? Do the pads have a chamfer on the leading edge? Some do, and some don't. If not, I've seen the lack of a chamfer cause a vibration. Easily cured with a grinder. You don't need a big chamfer. 1/4 inch should do it.

If you reused the old pads (a false economy IMHO), were they glazed? Which may have been your original problem. When you put on the new rotors, did you clean both sides with brake cleaner? This is a dirty procedure. Getting dirt/grease on your pads will cause grabbing when you apply the brakes.

Did you clean and grease the guide pins? Having sticky pins will affect how the caliper closes and retracts. How are the pin bushings? If there is alot of play, the calipers don't close in parallel and they can get cocked.

How are your steering components? Idler arm and tie rods. Lots of joints in the whole process other than just the control arm ball joints.

Hope that helps.

Don
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