vibration while braking
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Instructor
Joined: Jul 2011
Posts: 126
Likes: 12
vibration while braking
I developed vibration in the steering wheel while braking with my 1994 964 Turbo Look (C4), sometimes very pronounced.
I installed new front end (tie rods, shocks, etc) in the past and it drove fine...
But very recently I installed new rotors and pads and new tires were installed about 2 months ago.
Wheels were balanced and car was aligned at that time.
What could this be? Warped rotors, wrong brake pads?
Any pointers appreciated. Thx.
I installed new front end (tie rods, shocks, etc) in the past and it drove fine...
But very recently I installed new rotors and pads and new tires were installed about 2 months ago.
Wheels were balanced and car was aligned at that time.
What could this be? Warped rotors, wrong brake pads?
Any pointers appreciated. Thx.
Three Wheelin'
Joined: Mar 2017
Posts: 1,971
Likes: 238
From: Northern California
Jack up your car until the wheel clears the ground. Spin the wheel, it will be tight due to the pads riding on the rotors, but if there is a spot that jams the rotors, then you know the rotor has a high spot due to warpage. Bear in mind if your rotors are not warped, there will still be some binding due to the pads touching the rotor. What you are looking for is a consistent binding, not a particular tight spot that jams your rotor. If you have that then the rotor is warped. Unfortunately you cannot turn a drilled rotor and the only option is to replace it. If it is new try to get n touch with the seller to see if they will stand behind it.
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Joined: Dec 2018
Posts: 74
Likes: 33
I developed vibration in the steering wheel while braking with my 1994 964 Turbo Look (C4), sometimes very pronounced.
I installed new front end (tie rods, shocks, etc) in the past and it drove fine...
But very recently I installed new rotors and pads and new tires were installed about 2 months ago.
Wheels were balanced and car was aligned at that time.
What could this be? Warped rotors, wrong brake pads?
Any pointers appreciated. Thx.
I installed new front end (tie rods, shocks, etc) in the past and it drove fine...
But very recently I installed new rotors and pads and new tires were installed about 2 months ago.
Wheels were balanced and car was aligned at that time.
What could this be? Warped rotors, wrong brake pads?
Any pointers appreciated. Thx.
Its time to replace your trailing arm bushings in front!
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Rennlist Member
Joined: Mar 2003
Posts: 9,065
Likes: 1,195
From: NY Tri-State
Did you bed your pads after you installed them? Also, you should avoid changing pads and rotors at the same time as it is really hard to bed the pads properly. I doubt your rotors are warped unless you took the car to the track or the German Autobahn.
Three Wheelin'
Joined: Nov 2005
Posts: 1,250
Likes: 44
From: Bahrain = somewhere in the Middle East
I would check, in order:
I've been where you are a few times. The issue has been, for me, point 2, point 3 and one time the tires themselves. The tires was simply a try to see if things got better, since everything else was checked and confirmed to be fine.
I had the rotors turned with the ProCut tool (I think that is the name) once and it made a little difference, but ultimately the tires fixed the problem. Went from Pirelli P Zero Rosso to Conti Extreme Contact DW in 2012 or so.
- Front tire wear pattern
- Front wishbone bushings
- Steering components (even as far as rack and steering column)
- Brake rotors (check if they are true)
I've been where you are a few times. The issue has been, for me, point 2, point 3 and one time the tires themselves. The tires was simply a try to see if things got better, since everything else was checked and confirmed to be fine.
I had the rotors turned with the ProCut tool (I think that is the name) once and it made a little difference, but ultimately the tires fixed the problem. Went from Pirelli P Zero Rosso to Conti Extreme Contact DW in 2012 or so.
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Rennlist Member
Joined: Mar 2012
Posts: 17,248
Likes: 2,218
From: SoCal
Right, rotors really don't warp and I've had many times I come off the race track with brakes smoking, but they CAN get deposits.
Typical vibration check points:
rotor deposits
tire balance
tire issues
wheel bearings
control arm bushings
shock bushings
shocks
Typical vibration check points:
rotor deposits
tire balance
tire issues
wheel bearings
control arm bushings
shock bushings
shocks
Three Wheelin'
Joined: Nov 2005
Posts: 1,250
Likes: 44
From: Bahrain = somewhere in the Middle East
Low tire pressure also contributes to this - a remarkable amount for me, with our wavy, tram lining tarmac at the lights.
Nordschleife Master
Joined: Jul 2007
Posts: 5,613
Likes: 52
From: DFW, TX
Yea. Check those front control arm bushings.
Illustration of what the control arm does with bad bushings.
http://www.jackals-forge.com/lotus/9...shbone_pry.wmv
Illustration of what the control arm does with bad bushings.
http://www.jackals-forge.com/lotus/9...shbone_pry.wmv
Rennlist Member
Joined: May 2002
Posts: 23,303
Likes: 511
From: Baltimore, MD
+1 on pad deposits. Would get them from time to time with the race car. Pagid Oranges created the issue. Popping in a set of Hawk Blues (very abrasive) cleaned the rotors in a few miles.
Rennlist Member
Joined: Jul 2017
Posts: 1,830
Likes: 357
Ive had the pad deposit issue as well. In my case I it occurred with new pads and rotors by holding the brakes while stopped while the were very hot. Causes a strong judder from then on when braking. Since then I always try to replace the pads on used rotors and make sure I dont hold them while stopped without fully bedding them in. Some pads are more sensitive to this than others.
Pete
Pete
