Installed bullitt brakes: Problem!

[waggs]

i installed bullitt front brakes on my car yesterday and i have a problem. whenever i'm going 40mph and apply the brakes i get this pulsating feeling in the brake pedal. it doesn't pulse as fast as the abs kicking in, it seems to go with the rotation of the wheels. i can't feel it in the steering wheel but i can hear the noise. it sounds like a thumping sound. i'm pretty sure i lubed all the contact points good.

i went outside a few minutes ago to check the rotors and i noticed that the drivers side pads weren't contacting the rotor as much as the passenger side. what could cause this? is this where my thumping sound is coming from?

 

[darkside03gt]

double check the torque on the bolts attaching the calipers to the spindle. also make sure your pads are correctly installed they should be seated in the caliper bracket. dumb question but did you torque your lug nuts? You could also potentially have a broken pad. its rare but it has happened.

 

[Mustang5L5]

I'd also slap some high temp paint on those rotor hats otherwise you'll have brown rotors in a couple weeks

 

[waggs]

double check the torque on the bolts attaching the calipers to the spindle. also make sure your pads are correctly installed they should be seated in the caliper bracket. dumb question but did you torque your lug nuts? You could also potentially have a broken pad. its rare but it has happened.

i tightened the mounting brackets good. i was reading a bunch of old threads here and i found out that they should be torqued to 85ft lbs i'll do that tomorrow.

the lugs were torqued to 100ft. lbs. one of the pads might've broken. i'll check in the morning.

looking at the pics side by side, it looks like the drivers pads aren't even applying at all. maybe siezed caliper? i got the brakes from a wrecked bullitt. hopefully this wasn't the reason they wrecked

 

[waggs]

I'd also slap some high temp paint on those rotor hats otherwise you'll have brown rotors in a couple weeks

yeah i have the silver spray paint in my garage, i'm gonna put it on next weekend. i was just waiting for the pads to fully seat so i know where to paint

 

[darkside03gt]

you bled the brakes also right?

 

[Mustang5L5]

It's possible. You could try placing a block of wood in the caliper and pressing the pedal to force the pistons out (but not too far). Perhaps one is seized.

 

[waggs]

yeah i bled the brakes. i kept the resovior full while i was bleeding them too. i'll try the block of wood tomorrow and see if the caliper is ****ed. are they rebuildable? or will i have to buy a new one?

 

[BobHyatt]

yeah i bled the brakes. i kept the resovior full while i was bleeding them too. i'll try the block of wood tomorrow and see if the caliper is ****ed. are they rebuildable? or will i have to buy a new one?

Depends. If you can get the piston(s) out, then anything can be rebuilt. But if it is rusted in solidly, you might find it impossible to extract the thing. Best bet is the block of wood, with motor cranked to get the hydro-boost kicking in and see if you can develop enough pressure to push the caliper out. Once out you can remove any rust easy enough...

BTW 99% of the time, pedal pulsation is a direct result of a warped rotor...

 

[Mustang5L5]

I know they have rebuild kits for the 38mm Cobra caliper used 94-98 as I've rebuilt a pair. They are just 2 rubber seals around the pistons and two piston boots. Pistons can be bought separate but if the bores are pitted you need a new caliper.

The newer 99+ calipers are 40mm bores. Haven't found a kit for them yet (but i haven't really looked)

 

[flstang65]

are they new rotors? if not they could be warpped

 

[waggs]

yeah the rotors are new. wouldn't warped rotors make the steering wheel shake too? i can only feel it in the brake pedal.

 

[BobHyatt]

yeah the rotors are new. wouldn't warped rotors make the steering wheel shake too? i can only feel it in the brake pedal.

If you drive very slowly, and lightly press the brake, you will feel a warped rotor as the brakes drag and release due to the warp. If a caliper is rusted, it won't provide any braking, and it won't provide any pulsing or anything else since it is not moving... If you feel the drag-release-drag-release in the above test, you have a rotor problem. And we have seen problems with new ones. But make sure the rotors are on properly as well. If they don't sit flat on the hub, that is an artificial warp.

If you want to test for warp, do this. take the wheel off, and then use washers and lug nuts to clamp the rotor onto the hub with the wheel off. Take a coat hanger and straighten it out and attach it to the caliper or spring or something solid, and then bend the tip so that it just barely misses contacting the surface of the rotor. Now rotate the rotor by hand watching to see if the gap opens up or closes as it rotates. If so, the rotor is either not seated or it is warped. If you have a dial indicator, so much the better for this test.

 

[RedDaemon]

yeah the rotors are new. wouldn't warped rotors make the steering wheel shake too? i can only feel it in the brake pedal.

depends on front or rear brake problem. at least in my experiences


did you properly "break in" (no pun intended) your breaks?

 

[03TrueBlue]

Did you have the rotors turned? I always turn new rotors being the lay around so long on their sides and they will sometimes warp a little. The problem you are talking about is the same thing mine had and it was a very small warp. Turned them and fixed it. Also if you have a frozen caliper it should pull one way if its on the front when you hit the brakes.

 

[Mustang5L5]

Does the car pull to the side during braking?

 

[RedDaemon]

so did he crash the car or what? what happened to this thread.

 

[waggs]

no i didn't crash the car brakes amazing and everything but the knocking sound is still there. i'm guessing it's the rotors. i'm gonna get them turned this weekend so hopefully that fixes the problem. i made a vid a few nights ago of the braking. everything works fine but the steering wheel shakes violenty back and forth which leads me to believe it's the rotors.

YouTube - brakes

i let go of the steering wheel at 6 seconds in. i start braking at 7 seconds.