The problem: Under heavy (near threshold) braking , my car is pulling strongly to the right. The steering wheel does not seem to move, but the car arcs notably to the right. Very unsettling at speed.

Other symptoms:
--A right side tire is locking up - puff of smoke and black streaks on the rode (at 70 mph). While driving, my impression is that it is the right rear. However, the right front tire seemed to have the highest temps after repeated braking. Tires are AVS intermediates.

--There is NO air in the system and the brake pedal feels great. All calipers/rotors are practically new and in great condition.

The set-up:
Front: Willwood billet superlites with 11.75" rotors and carbotech Panther+ (4 events on this set-up.)

Rear: Hasty 11" single piece rotors with new stock rear calipers. Pads are are track-oriented Axxis pads (not metal masters).

My guess: I think I am overpowering the right rear, which only has 430 lbs on it. The left rear has 70 lbs more. The only thing I can think of doing is to put less aggressive pads on the back.

Misc fact:
The car had similar behavior when I had stock rear rotors with Panther + on the back. Previous set-up did not do it which was stock rear rotors with r4s on the back. That was a while ago, so who knows.

All advice appreciated.

 

I know you said they were new but it really sounds like a rotor issue. I had the same problem and it turned out that my right front rotor was warped.

 

Richmond Va, huh?
where in Richmond....?
<----lives in Fan area, near Carry Town.(west End)

As for your breaking problems, hmmm?
Is it only from the backs that you are getting this or does this happen to the fronts, I could not really understand that in your post? Try a less agressive pad in the rear like you said because running track pads over a upgraded pad does make a bit of difference. Try running carbo techs just in the front, and stock pads in the rear, all your stoping power well the majority is in the front anyways.

Edit: and the rotor can be warped too...doh forgot to mention that but Freek24 did so its all good.


[Modified by AcuraRacer112, 7:29 AM 6/24/2002]

 

I live in Mechanicsville - Just 15 minutes or so from the fan - we should do lunch sometime.

Rotors are definitely not warped - confirmed with a run-out gauge.

Please keep ideas coming.

 

A few non-brake possibilities. Some may not apply to your car:

Alignment.

Worn suspension bushings.

Coilovers that need cornerweighting.

Unibody bent due to prior accident.

 

Great minds think alike:

Car was just cornerweighted and aligned. 49.8% cs 59.3 Crossweights.

Zero toe w/ 2 degrees camber all the way around.

No accidents in last 8 years.

Bushings are in reasonable shape.

 

I had the same symptom on my streetable track mule. I was running -1 3/4 camber all around, P+ pads front and rear, and 0 toe all around. I suspected that the P+ in the rear was going to be too agressive and it was; the ABS was releasing the rears long before the fronts were at threshold and the back of the car wanted to go left under hard braking. I put stock pads back on the rear and set the rear toe at 1/16 in total. The car now brakes in a tidy straight line with just a touch of left/right rear drift when I'm right at the limit. I'm not sure which change cured the problem, but I suspect the heavy rear braking was the root cause. I'm going to stick with the slight rear toe in since I run the Mugen 26 mm rear bar.

If going less aggressive on your rear brakes does not cure it, try a little rear toe in. Check your line pressure at each caliper, your proportioning block might be sending more pressure to your RF caliper?

 

Stuck or sticking caliper?
Crimp in a brake line somewhere?

 

Consenus typically seems to be to strive for even cross-weights so I am in the minority in this thinking, but you may have enough difference in vertical load on the left and right fronts to give you lock-up and/or pulling problems. On a front drive car, I think there is a case to be made for striving to equalize the fronts and letting the rears fall where they may. You may already be doing this, since I don't understand what you mean by "49.8% cs 59.3 Crossweights".

Kirk

 

Sorry for the typos. What I mean is LR+RF = 49.8% of the total vehicles weight.

 

was (re)reading Carroll Smiths book Tune to Win and he mentions that almost never are steering or pulling issues under hard braking are really caused by brakes. its usually the suspension. for example, if the castor is off for any reason on one side, then that would upset it enough to cause your problem. or any other suspension irregularities, recheck em all, also one shock may be worn out.


[Modified by Tyson, 1:53 PM 6/24/2002]

 

are you running stock rubber brake lines, or are they stainless?

 

Lines are stainless. Castor looks good. Appreciate the thoughts.

 

I had a similar issue when putting new pads onto my car. Check the LEFT front, and make sure that you are getting a full pad on the rotor.
I had the shim work it's way between the pad and rotor, and it wasn't getting a full bite.
A small amount of pull to the right is normal.
And as for locking up the right rear, put some weight over that corner.

 

i have the same wilwood 11.75 and fastbrake rear set up as you do. Exact same thing happened to me once in autox. the car will pull right under heavy braking. but it only happened once and I suspect its the rear disc is just too big and lock up. I never had this problem before I install the kit. But now its just went away and never does it anymore.

 

Okay - what is the raw left/right split in the front (with driver and all that)? If it is more than 100#, that gets my guess $.

Kirk

 

Hi,
Could you explain the "small amount" is normal angle to me.

 

Here's an update.

Took out Axxis ultimate pads from the rear and put in the $25 raybestos pads from pep boys. Initial impression is that the pull to the right is less frequent and less severe. The right rear is no longer locking up and bracking balance is pretty good. The car still feels a little squirrely under heavy braking - particularly as you approach lock-up.

It may be that I just have too much brake on the car for street tires. ( I can lock up the fronts below 60/70 mph or so.

I will check the bushings tonight to be sure.

Weight distribution (Driver & 1/2 tank of gas)
LF 813 RF 755
LR 501 RR 433

Thanks again for all of the input folks. - Phillip

 

I dont know if its been mentioned yet (didnt feel like reading through all the posts), but I had the same problem a while back. All I did was bleed the brakes and everything was back to normal. If you have any air/shitty boiled-over fluid, it was cause one caliper to apply less pressure on the pad, therefore less braking torque, therefore will pull to the opposite side of that which needs to be bled. Was that a run-on sentence?? Just bleed your brakes