Locked Brakes!

You guys know any reason why the front 2 tires of a RWD car would lock up? First one would only lock up, then took the wheel off and inspected that, then it seem to rotate fine after that, gave it a shot again and then the other one started to lock up.. suggestions?

Pop off your calipers, clean up the sliders, lube them up and throw it all back together.

ill give it a shot , best advice ive been given so far

If i can't figure out whats wrong tonight, anyone know of any good shops that can rebuild z32 calipers?

calipers seize but its pretty rare, how do they look? really rusty and shit? I'm sure you've checked for kinked lines already. what does the pedal feel like?

Do they look on after driving a bit, and then back off after the car has sat for awhile?

I inspected it tonight, the rotor is warped and bent, and is very difficult to spin. I'm pretty sure that is my problem. I have new rotors and pads all around ordered

The rotor is warped and bent?

locked2 wrote:

The rotor is warped and bent?

Warped/bent

I cant even imagine how warped a rotor has to be to lock up the brakes.

That isn't going to be your problem, the problem is going to be in the caliper itself. Once you release the brake pedal, there is no longer pressure on the caliper and it is able to retract again. Your problem is something that is stopping this from happening. You said they are Z32 brake, so forget about the sliders that I was talking about, that won't apply.

I don't see how there is any way for a warped rotor to cause your brakes to lock up. Without hydraulic pressure on the brakes, the pistons are free to retract. There isn't going to be enough run-out to span the gap on fully retracted brakes and lock up your brakes. If your rotors were as bad as you think they are, your front end would have felt like it was ready to fall off whenever you hit the brakes before. Warped rotors are very easy to feel through the pedal.

Get your calipers re built, or just rebuild them yourself. It isn't hard to do.
http://www.nicoclub.com/archives/rebuilding-300zx-z32-calipers.html

Sometimes it can be a little bit of a bitch to pop out the pistons, even when you do use are like they show. They get corroded in there, and that is why they lock up on you.

DOMS14 wrote:

That isn't going to be your problem, the problem is going to be in the caliper itself. Once you release the brake pedal, there is no longer pressure on the caliper and it is able to retract again. Your problem is something that is stopping this from happening. You said they are Z32 brake, so forget about the sliders that I was talking about, that won't apply.

I don't see how there is any way for a warped rotor to cause your brakes to lock up. Without hydraulic pressure on the brakes, the pistons are free to retract. There isn't going to be enough run-out to span the gap on fully retracted brakes and lock up your brakes. If your rotors were as bad as you think they are, your front end would have felt like it was ready to fall off whenever you hit the brakes before. Warped rotors are very easy to feel through the pedal.

Get your calipers re built, or just rebuild them yourself. It isn't hard to do.
http://www.nicoclub.com/archives/rebuilding-300zx-z32-calipers.html

Sometimes it can be a little bit of a bitch to pop out the pistons, even when you do use are like they show. They get corroded in there, and that is why they lock up on you.

the dude slammed into a curb/wall sort of thing, how he explained it, and I'm positive its that it is bent. It'll spin by hand partially like 3/4 of the way but once you hit the bent part. It'll be a big bitch to turn. I got new brakes on the way anyway., also the calipers look like they were just rebuilt and are pretty new. my theory if its difficult to turn with the wheel off, imagine with the wheel on and the car set down on the ground with the weight of the engine and car on the wheel. Causing it to be difficult to rotate, and just slide on the dirt and grime on my garage floor.

If you hit a curb or "wall sort of thing". Hard enough to bend a rotor. Id take a look at the bearing on that side aswell.

Jason- wrote:

If you hit a curb or "wall sort of thing". Hard enough to bend a rotor. Id take a look at the bearing on that side aswell.

I was just going to say that. When you have the brakes off, get a dial indicator and magnetic base and check the run-out on that hub. Also look and your lower control arm, front shock, tie rod, sway bar end links.. basically everything associated with that front suspension/ steering.

This is that white Silvia off Kijiji isn't it?

don't know if it was on kijiji or not. But yeah i replaced all parts associated with the front suspension already, tie rod sway bar end links, lower control arm, and front shocks, also replaced the inner tie rod , ill check out the hub in a few days when i have some time.