RaleighSS

hoping to grab a few more ideas ....

C5 Z06 stock braking system with SS lines. I am getting a pull to right side on initial application of brakes does not seem to matter rate of application (hard panic or soft normal stop) and only seems to be on inital application if you hold it straight through the first pull to right you can let go of wheel and does not pull to right its just that first hit..

Steps done so far
Bled entire system
removed left front caliper pulled 2 pistons out and made sure nothing wrong or sticking cleaned and reinstalled
Changed pads from PFC to Stock PBR pads
Cleaned and inspected all rotors
Inspected for leaks on all lines


Have not
replaced rotors
installed brand new pads

Recent work
Oil pan removed (so had to drop part of front end i think)
New Front Rack with new tie rod ends (was leaking so had to replace)
Track alignment by Long Road Racing .. they have done it for me many times.
T1 Sway bars installed (verified they are neutral)

Let me know your thoughts ...

crease-guard

The only other thing I could think off the top of my head is to make sure you don't have a loose wheel bearing. It almost sounds like you are getting some sort of piston knock back on the left side since it just happens on initial application.

I had a similar issue and turned out I didn't torque down the wheel bearing bolts thus causing the rotors to wobble and causing the piston knock back.

froggy47

Did they turn the rotors? What does "clean" the rotors mean?

ErnieN85

check the brake lines a partial collapse of the line can cause a delay of pressure to one caliper (left side?)

sperkins

Had to fix this same issue recently for a customer that had an alignment done at one of the big name shops. Camber and toe was set, but the caster was jacked beyond belief.
When the pan was replaced, the whole front cradle had to come loose. I would check the positions of all 4 of the front eccentrics to make sure they're relatvely close in comparison to each other.

RaleighSS

Oh I just cleaned them very good just in case some fluid / oil or whatever got on them ...

RaleighSS

Ok good idea ... i can check the bearings but also maybe tap the brakes a bit to see if i can get rid of the knock back

froggy47

When you change pad compounds you should always sand the rotor or do a light (lathe) turn and then bed in the new pads per mfg instructions, ck to see if you have any glaze spots, pad deposits etc on the new pads & on the rotors.

RaleighSS

Ok i considered that but I have always been switching from track pads to street pads for the run home and never had any issues. When I had the PFC on the grab was much worse just because I think the bite on those pads is much better...

froggy47

All these other suggestions are good also, but that would be the first thing I would ck, also since you say it's a quick pull then they work ok.

It may also wear off if it's a small glaze spot, but if it's a glaze on the pad you may need to redo the whole thing.

moespeeds

2nd the loose wheel bearing or hub suggestion. I had this exact problem one weekend, then the next weekend lost the brakes due to pad knockback. When I got in the pits I found I was missing a bolt in the hub and a 2nd of the 3 was loose.

RaleighSS

ok ... Hub and rotors are my next focus point ... guy up the street turns rotors for 5 bucks so may do that just to see

moespeeds

First thing you should do is jack up the front end and grab that wheel and try to shake it side to side and up and down, see if there is any slop there.

RaleighSS

Yes ... going to inspect that hub heck all hubs first then move to the rotors also will look at the lines again make sure I did not miss something there ....

waddisme

Wouldn't he want to check the hub on the front left for the pad knockback? If it pulls to the right, then the right caliper is gripping before the left?

RaleighSS

yes that is the side i am going to focus on tonight :-)

Grabbed_Crow_Mobe

Try swapping the rotors and pads from left to right and see if the pulling follows directions. If not, you can rule out rotor/pad possibilities.

RaleighSS

Put another set of back up rotors and backup pads on and same problem ... checked hub and could not make it move at all on both sides front. I have not focused on rear is it possible for rear to be grabbing and pulling car to right ?

CONE RACER

Another thought is to check your all your caliper pins for full, smooth, slide motion.

Last month I was chasing a slight yaw (a little less than a "pull") to the right with the car when braking at track speeds. I had done several of the same steps you are doing. Turned out to be just one of the caliper pins on the left rear brake was sticky at a certain position. Didn't notice it when I pulled the caliper or changed the pads. Cleaned and lubed and it fixed the problem.

RaleighSS

Did that on the front will look at the back tonight.

Hubs are old on all 4 corners (original) but have 0 flex or movement while they may need to be replaced on principle I cant see how they have anything to do with this problem as I cant move them at all