Uno99

iTrader: (2)

I just finished changing my rotors and pads. Irotors / Hawk HPS pads. I used a c-clamp and made sure the cylinders were compressed back and put plenty of caliper grease on the clips and back of the pads. I can hear the pad slightly rubbing the rotor when the brakes are not applied. Last time I did my brakes this did not happen. Any ideas what I may have missed? Will this go away after I season the rotors and bed the pads?

Uno99

iTrader: (2)

Anyone hello, Any ideas please.

3rdgenguy

iTrader: (1)

are the pads ceramic?

Uno99

iTrader: (2)

Not sure. They are hawk HPS

trackbird

iTrader: (4)

Hawk refers to them as "Carbotic" pads. It's not ceremic, and it's not quite carbon metallic....

You could have a bit of rotor runout or you might have rust built up on the hubs that is not allowing the rotor to sit flat on the flange. These are the first things I'd check. You can remove the wheel, spin the rotor (snug 5 lug nuts down on the rotor to keep it from just "flopping around") and see if it runs true. If not, you might want to pull it off and take a wire brush to the hub to clean it off and see if that helps. If not, you might try another rotor and see if it spins "true". That will help you find out if it is a rotor or a rust problem. At least that's where I'd start.

LS1powerhouse02

iTrader: (9)

you also might want to check the boots on the brake caliper pistons. Your caliper could be hanging up slightly. Mine did the same thing......my boots were ripped and i was going through pads way too fast. Just an idea.

Uno99

iTrader: (2)

Caliper are new rebuilts. I will check it out. Thx

JasonWW

iTrader: (2)

You don't put grease on the back of the pads. You want the opposite. You can put the tacky no-squeel stuff them if you want. What clips did you grease, the upper and lower ones the pads sit in? That's OK.
There is a special hi-temp brake grease you can put on the clips as well as the guide pins.

If your only problem is the pads rubbing very slightly while not on the brakes, then I would just drive it a while and see if it goes away.

If you suspect the caliper is not completely releasing, you can check by starting with the car cold, drive for about 5 minutes and then check the caliper temps with your hand. The 2 fronts will always be warmer the the rears. Make sure the 2 fronts are about the same temp as well as check the 2 rears the same way. If one side is noticably warmer than the other side you may have a caliper dragging and building up friction while not on the brakes. Assuming you put all the parts on correctly, it would be a caliper issue and it would need to be replaced.

trackbird

iTrader: (4)

Post #2.

http://frrax.com/rrforum/index.php?a...261&hl=grease&

And the post from lateapex on May 24th at 13:18

http://frrax.com/rrforum/index.php?a...2&t=4563&st=15

JasonWW

iTrader: (2)

Kevin, you can qoute Bob all you want. You haven't convinced me. Have you asked him about this in particular?
Most folks just throw away the pad shims. When your brakes squeel, some people will go to great lengths and spraying some of the blue, tacky, anti squeel spray on the backs of the pads to stop it is worth the scarifice of not allowing the pads to slide around. Not allowing the pads to slide around may have no effect at all, so it wouldn't really be much of a sacrifice.

Let's get Bob over here if you think I'm wrong. He may know something specific about these calipers that I don't. Still, it would be a moot point if one of the caliper pistons is not retracting and that is the cause of the noise.

If I sound upset, I'm not. My typing does sound a bit angry to me though.

trackbird

iTrader: (4)

I've seen more than one set of hawk HPS pads, which have shims that are "stickied" and riveted to the back of the pads with the shims torn off of the rivets and wrinkled up in a "pile" which required us to pull the calipers and remove the remains of the shim. It seems to be caused by the "thrust" of the rotating rotor trying to push the pads away from the rotor (while there is enough brake force to effectively "stick" the shim to the caliper). Couple that with a little play in the pad abutment bracket and a lot of brake force that "clamps" everything together tight and it will try to walk the pads out from under the shims and the caliper "fingers". As the rotor spins into the pad, it's at an angle and that produces a force trying to push the pads off of the outside of the rotors surface. Also, we're dealing with calipers with equal sized pistons, so the leading edge naturally gets more clamp load as the pad bites and is pulled by the rotation. These forces together are what can wrinkle the shims and the reason it is suggested to lightly lube the backing plates. It helps keep the system "floating" and prevent the clamping force from "locking up" the pad/caliper interface to where it can't move independantly.

Did that make sense?

JasonWW

iTrader: (2)

Yea, that makes sense. Still, a lot of people throw away those shims. Most brake pads for other cars don't use any kind of shim between the caliper and the pads. Normally you would put the tacky spray directly to the back of the pad. That can make the difference between squeeks and quiet.

Uno99

iTrader: (2)

Well it turned out to be the metal brackets that the pads sit in on the caliper brackets. Seems the new one were a bit too big and were rubbing slightly. I lubed up the old ones and everything is fine now. Thx for the replies The irotors look sweet and the hawk pads really bite and resist fade. Very pleased with the combo.

slimcracka

iTrader: (7)

not to get off the subjust but i recently changed my rotors and pads and on the passanger side on the out side of the rotor onle the caliper is only grabbing the top inch or so anyone else had this problem? btw there power slot rotors and hawk pads..thanx
justin

JasonWW

iTrader: (2)

It's not really a problem. Your calipers have just spread a little. They all seem to do that to some extent. Just keep driving on it. What will happen is that the smaller contact patch will apply more pressure and wear the high spots on the pads down quicker. After a couple of weeks the pads will get matched to the shape of the rotor and they will be making full contact at which point the pad wear rate will be back were it should be. I think everyone goes through this, it's really nothing to be concerned about. See how they look after a couple of weeks of driving.

slimcracka

iTrader: (7)

thanx alot i was really kinda stressing it a lil bit but i kinda thought it wasnt that bad cuz the streering wheel doesnt jerk when i get on the brakes... thanx again..