Car -pulls- to left or right when braking

**OLJustice** · 05-03-2008, 05:06 AM

Title says it all. My car pulls to the left or right when braking from lets say... over 40mph or so. This is NOT a vibration. I had a vibration about 5 months or so ago and had the front rotors and pads completely replaced. The vibration is gone but lately I've noticed that the car will pull to the left and then to the right (or visa-versa) under hard braking. I mean I will literally see the steering wheel move slightly in either direction.

This is very scary if braking hard in a lane in between 2 cars. I have to be very conscious to countersteer and keep her straight. Any suggestions? This is very dangerous. Again, my front pads and rotors are only about 5 months old.

Oh, and she always squeals horribly under very light braking (not when full force is
applied)

**OLJustice** · 05-03-2008, 10:43 AM

anyone ever heard of this happening?

**sidetrack** · 05-03-2008, 12:40 PM

Rotors and pads would be the first place to look. But yours were recently replaced. Maybe something is leaking on the pads causing inconsistent braking? I would take the car back to the your brake installer. Maybe their install went bad.

**jhs914** · 05-03-2008, 12:42 PM

That is a classic symptom of brake fluid leaking on to the brake pads. Pull the wheels and check for signs of fluid leakage.

**skeletonizer** · 05-03-2008, 01:05 PM

Do you have stock rotors? It is possible (not probable) that you are experiencing "knock back".

If this happens after hard cornering without brake applied. The outboard brake rotor can flex enough that as it travels through the caliper it's at a slight angle, thus forcing the piston(s) back into the caliper. The pull is experienced when the unaffected brake grabs before the slack in the other one is taken up.

If you preload your brakes when approaching a corner it will minimize knockback. The problem has been adressed electronically in the Challenger SRT8 by using the ABS pump to keep the pads against the rotors.

After reading about this I went out and tried to make it happen in my SRT. I think that it would have to be very extreme driving to make it happen as I could only slightly feel it and only after a four wheel drift.

It was fun though.

**OLJustice** · 05-03-2008, 01:15 PM

Originally Posted by jhs914

That is a classic symptom of brake fluid leaking on to the brake pads. Pull the wheels and check for signs of fluid leakage.

Where would I look for fluid? I'm assuming it wouldnt be on the rotors since they are constantly being "wiped" by the pads. Maybe on or about the caliper?

**OLJustice** · 05-03-2008, 01:17 PM

Originally Posted by skeletonizer

Do you have stock rotors? It is possible (not probable) that you are experiencing "knock back".

If this happens after hard cornering without brake applied. The outboard brake rotor can flex enough that as it travels through the caliper it's at a slight angle, thus forcing the piston(s) back into the caliper. The pull is experienced when the unaffected brake grabs before the slack in the other one is taken up.

If you preload your brakes when approaching a corner it will minimize knockback. The problem has been adressed electronically in the Challenger SRT8 by using the ABS pump to keep the pads against the rotors.

After reading about this I went out and tried to make it happen in my SRT. I think that it would have to be very extreme driving to make it happen as I could only slightly feel it and only after a four wheel drift.

It was fun though.

This occurs after braking relatively quickly (but not like ABS-Engaging speeds) from.. Oh i'd say 40mph or more. Your theory seems plausible, although it happens to me after straight acceleration :(. To further the description -its like the car suddenly jerks to one side or another after braking. Sometimes it'll go left THEN go right. We're not talking like 90* turn pulling here. But enough to jerk me into the next lane if I let it do what it wants. The wheel follows b/c I can feel it through the wheel. I mean you can actually see it turning slightly. Very very scary.

Rotors are stock. They were replaced by the dealership. Pads are semi-metallic Mopar "Value" brakepads (yeah, I went cheap). A quick trip to RS Strauss revealed that the rear pads have about 35% left on them and the fronts are good (they didn't give me a percentage). Again, I get no vibration so I dont think they are warped, just this really scary & dangerous pulling problem.

**ephines** · 05-03-2008, 05:54 PM

This has happened to me. You need check the balance and the air pressure. The brakes were calibrated for stock RT not SRT rotating mass(38 vice 49lbs).

**OLJustice** · 05-03-2008, 06:04 PM

Originally Posted by ephines

This has happened to me. You need check the balance and the air pressure. The brakes were calibrated for stock RT not SRT rotating mass(38 vice 49lbs).

Update: After a quick jaunt to Jersey, I realize that it happens braking from ANY speed. Not from over ~40mph as originally thought. So long as I apply the brakes in a constant linear and firm fashion, it will happen.

I will go out and check my tire pressure right now.

**BrilliantBlackHemi** · 05-03-2008, 07:23 PM

You might could take emory cloth and clean off the rotors, then go out and bed in the brakes again. That may help alot.

**Hemi31** · 05-03-2008, 07:30 PM

You also might want to check the tie rod ends.

**BobCrespo** · 05-03-2008, 07:36 PM

Could also be a Caster pull check the bushings.

Bob

**MikeEast** · 05-03-2008, 08:14 PM

I kinda like Erik's 'check the tie rod ends' - but I think that would also show up as a bit more play in the wheel when driving straight as well. At least all the ones I've replaced over the years felt like that. My 64 VW Transporter had about a 1/4 turn of the steering wheels worth of slop in it.

Mike

**OLJustice** · 05-03-2008, 09:54 PM

I checked pressure. Tire pressure is equal on all wheels within +-1psi. I guess the next step is checking tie-rod ends. I truly hope this isn't the issue as they were supposedly replaced at the dealer about 3 or so weeks ago.