Contour Enthusiasts Group Archives Forums General Troubleshooting Pulling under braking

1999 Mystique, ATX, Discs/Drums.

Pulls hard left under braking conditions.

Runs straight under normal driving conditions.

Changed rear drum brakes

Changed out RF Caliper

Swapped pads from side to side

Changed hoses.

What can I check next, I'm running out of ideas.

N.B. No noises or other drivability issues are present.

Check you ball joint, tie-rod ends and check the rotor on that side for run-out.

You should replace calipers in pairs. If you haven't replaced the LF caliper start there. Have you bled the entire system? Are the rear shoes adjusted correctly?

Do you have an infrared temp sensor? Can you barrow one? Measure temp of rotors after a couple of stops, the temps should be even side to side.

Ball joints & tie-rods are okay from visual inspection.

Lines were bled also.

Rear shoes were fitted to spec (as I was told).

Stupid question here ... what is 'run-out' ?

Also, using the IR heat sensor ... how do I interpret difference in temps?
FL rotor also seems to not have worn properly. Appears more shiny from a visual inspection. This is what prompted me to ask the wife is braking was okay

Apply the hand brake while rolling down the road to see if it pulls then. If it doesn't you know the problem is probably in the front - unless the proportioning valve is screwed up.
Run out is the disc wobble from side to side. There has to be a little built in to push the piston in a wee bit when you release the brakes. Too much will make the front end vibrate or you will feel like you are riding on the head of a pigeon!

The higher temp rotor will be the side the car pulls to. Run-out would cause a vibration while braking the limit is .001 total run-out.

Jack the front of the car up and pump the brake pedal a few times with the car off, then try to rotate the wheels, they should turn freely, if they don't you have a caliper that is either not releasing or the guide pins are frozen. Also check that the pads are not binding in the bracket.

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Run out is the disc wobble from side to side. There has to be a little built in to push the piston in a wee bit when you release the brakes.

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The rotor does not push the piston back in a wee bit. If the caliper is operating correctly the piston will retract enough to release pressure from the rotor.

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FL rotor also seems to not have worn properly. Appears more shiny from a visual inspection.

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Sounds like the LF caliper may be hanging up causing the pads to drag on the rotor and get to hot.

Check your spring. My car pulled to the left under braking and thats when I saw I had a broken spring.

If the brakes check out, take a look at your front control arm bushings.

Arms appear to be okay.

Was talking with a guy today who mentioned that there are three proportioning valves, and he suggests the rears ... does this make sense to anybody ?

Further information ... car still not finished though.

Hoses have been changed.

Master cylinder changed.

Drums have been turned (this helped a little).

Proportioning valves have been changed.

Suspension parts have been inspected.

Car now occaisionally pulls to the other side.

ANy further ideas guys ?