i searched but could not find much info.

I installed new front axxis ultimate brake pads.

I noticed when I drive that the front pads seem to be rubbing the rotor while I am driving, very slightly, noticeable at low speeds.

Even when I am not braking they make a small amount of noise.

I put the car in the air and noticed that rear pads seem to touch as well and make a small amount of noise when i turn the wheel.

Is it normal for pads to SLIGHTLY touch when not braking?

Could it be that the axxis pads make a rubbing noise that is more noticeable than the stock pads?

any help is appreciated

thanks!

 

It's normal for disc brake pads to make constant contact with the rotor surface, unlike drum brakes. Drum brakes have springs that retract the brake shoes away from the drums when you lift off the brake pedal. On a disc brake car, the pedal returns to rest in the up position but the calipers don't utilize any method of retracting the pads or caliper pistons (pots). That's why we often have to manually push the pistons back into the caliper body when replacing well worn pads.

I'm a little surprised that you can actually hear the brakes when you're not pressing on the brake pedal, though. Ultimates and other more aggressive race pads are noisier (tarmac pads in WRC cars are horrendously loud), but as long as you can freely spin the wheels when the vehicle is raised off the ground, I wouldn't be concerned.

 

Thank you wingless wonder, I was pretty sure that everything was OK, but your words gave me confidence.

I went out to the track today, Buttonwillow, no problems.

Everything went well, rotors/pads were not overheating due to rubbing.

I guess i'm just not used to running "track pads", it was my first time. The noise threw me off.


-A

 

its actualy not normal for the pads to touch( at least not noticable) if they were drums its normal. Did you compress the pistons back in when you changed your pads out?

 

to explain myself its true that the calipers dont use a real method of retraction but they should move back some due to the pressure being taken off of the piston(s). so there really shouldnt be any noise if you use a normal pad race pads i dont know about but everyday street pads they should move far enough off to make VERY little noise most deff not a noticable noise, this light contact is why pads glaze which is normal so dont let a brake service store tell you you have a problem with your car cause of glazed pads. Drum brakes DO have retracting springs but they pivot at either the bottom or the top (depending on the type of drum they are) and they DO touch the drum at that point they have to or else the parking brake wont be adjusted correctly and wont work right. check the piston and I dont know this yet but if the calipers used in the WRX are floating calipers you need to change the caliper sliding pins and the rubble sleeve EVERY TIME you do a brake service to your car (0r at least you should it keeps the floating side mobile so that it can slide and contact the rotor.) If it is a fixed caliper depress the pistons on BOTH sides. and as always use lock tite on the bolts holding the calliper to the car.

 

and one more thing the piston will always need to be pressed back in its the brake fluid pressure that pusehes it out and it will continue to move out to adjust for the wear of the pad. so much so that if your pads are rivited it will dig the rivets into the rotor.

 

oh and lastly did you resurface the rotors that could be it too...sorry so many posts just going over the touble shooting in my head for a brake job and things keep popping up.

 

Constant Contact with the rotor is normal. Pads travel a very short distance. BMWs utilize constant contact to keep the rotors warm to provide better braking in wet conditions.

 

it isnt normal for it to be audible

 

It does seem odd to be able to hear the brakes when they aren't being applied. I've used Axxis Ultimates before and Hawk HPS street pads, currently. Both generate more noise than factory pads (along with better braking) but I can only hear it when I'm actually braking. I can't actually hear anything when just cruising along or coasting, although I guess my catback exhaust and road noise might mask brake noise.

 

well im about a week from certified to do a brake job on any car in any shop so im tellin ya audible noise is not good and im sure he can hear this over his own road noise(or he wouldnt be mentioning it so it must be pretty loud) means something is not adjusted right im thinking that the rotors are warped and that the pistons might not have been pushed all the way back in this would make the pads hit the rotor in areas since the piston would be out to adjust for smaller (worn) pads. thats my two cents, also deending on the feel of the bake pedal there could be a problem there.

 

The rotors do not feel warped. Under light to heavy breaking, even on the track, I did not feel the pulsating pedal that is common with warped rotors.

Yes, I did push both of the pistons all the way back into the caliper before I installed the new pads.

No, I did not resurface the rotors. They were very even, smooth, and in overall good shape. But you are right, it is probably BEST to do a resurfacing if I were trying to be a certified, A++ mechanic that has a reputation to keep up with customers.

The noise is VERY SLIGHT. I have to go very slow, roll down the window, and pass an object that will reflect the noise, a fence, long wall, etc to hear the noise. Even then the noise is hardly noticeable, but came to my attention after switching to track pads.

I think that every thing is OK. I don't have any reason to believe the pads are glazed over or otherwise. But I should lube the caliper slider next time I do pads. I will be putting on the OEM pads soon so I will lube it then.

Will I need to bleed the brakes again after switching back to OEM pads? I think so...

 

i would recomend it (resurfacing that is), its porbly nothing at all since your windows are down and you need to be near a wall to hear it on my sh*ty chrysler i can here it and its normal pads on mine, though the car has loads of problems tht i havent got the money to fix. You should resurface the rotors though because enven if they are not warped they are worn and they are slicker than they should be, plus warping happens on the thousands of an inch scale meaning that you wont really be able to see it. i highly recomend resurfacing it at LEAST every other time especially when switching between pad types since the wear will be different., also resurfacing it will help with braking while the pads wear in( pads wont stop to well until at least 200 miles have been put on them though that distance may be shorter for race pads). as for bleeding it you wont really need to, the brake fluid should be fine even after a stint at the track. IF you knoticed some fade at the track though there could be air in the line or your fluid may have boiled and flushing and bleeding is a good idea at that point since the air once its there will always be there in the lines.

 

ok i dont know about the calliper build in the subaru, is it fixed: no sliding parts other than the pads?
is it a floating caliper: one side moves toward the inward pad and applys pressure to the outward surface?

if its fixed just get some graphite lube for the pad housing and lube that up nice this just makes it slide better to the disk.

if its a floating calliper then you ALWAYS lube up the sliding pins in the caliper, thats the pins that hold the "floating" side to the fixed side and allow the floating side to travel, they MUST be lubed and the rubber sleeve that they sit in should be replaced at a parts store that usualy runs 12 bucks for the rubber. if you dont want to replace them lube the crap out of those pins and push them in and out until it all slides nice and easy.

and when you put the caliper back on the assembly use white lock tite since its strong but not as strong as red, this makes the lock nice and strong but wont kill you to get them off next time you replace the pads.

 

oh and just a little info for everyone NEVER use air to clean out your brakes, the dust though it is not asbestos anymore is still NOT GOOD FOR YOUR LUNGS, use brake cleaner spray.