problem with brake pad not contacting rotor 100%

[TurDz]

This has happened to me twice now with two individual rotors. The first time, I installed my track pads and brembos, and on the rear right rotor (iirc), about 1/4'' of the very inside of the disc surface (closest to the hub) didn't contact the pad at all, and I only noticed this once rust started building up and turned slightly orange (a thin orange ring)

I thought it wasn't too major, but I have now reinstalled my stock OEM pads, and stock rotors, and the same thing is happening, but on the rear left rotor now. It's happening with a slightly bigger width, and on the very outside of the rotor surface.

I'm suspecting this could be the a slight problem with the clips? maybe they're not seated 100% into the caliper?

any input would be very helpful. thanks.

[vinhisbored]

well.. i know that you're not supposed to use used pads with new rotors.. (as in your brembos..) i think that maybe the oem pads are slightly smaller on the rotor, so that when you brake, the pads now arent touching your rotors at all (near the top). that happens to me, but i dont think that's really a biggie. your pads not contacting with your rotors would be more of a concern.

[TurDz]

Sorry if I wasn't clear. I used new track pads and new brembo rotors when I first replaced them. Now I swapped them back to my OEM used pads and used rotors (which were fine before I initially swapped them out).

[S14DB]

time to rebuild the calipers.

[OptionZero]

but they were fine on the track and street before and after (helped work on Turdz car...and paid the price! haha)

[vinhisbored]

are your brakes still grabbing though? or is it 'weaker' than usual?

[TurDz]

Well, my brakes are fine. It's just I know I have air in the system. I just finished bleeding with new fluid, and it feels so much better. I'm going to be driving about 1.5 hours, so I'll post back to see if that rusted ring is grinded off by the brake pads.

[OptionZero]

hey, you don't need to rebuild the calipers...just use the q45's we have lying around =P

[SimpleS14]

I'm going to be driving about 1.5 hours, so I'll post back to see if that rusted ring is grinded off by the brake pads.

That might led to uneven brake pad wear and possible squeaking noises. I had a simliar case happen with my car...that's why I say this.

[TurDz]

my update. About 2/3 of the ring has disappeared, and 1/3 still remains with very light rust. I'm thinking the rest will go away eventually.

The only thing I did was re-bleed my brakes (because we accidentally put air in the lines, not good). Maybe there wasn't enough hydraulic pressure on it. Because when I saw the air bubbles in the rear lines, WOW...it was a lot of volume (looking at the vinyl tubing, there was about 1 ft. of pure air between the fluid.

Thanks for all the help guys.

[TurDz]

I'm bumping this thread up again.

I looked at the race pads I swapped out, and one of the pairs has a slightly angled wear. Just barely, but noticable. It's not angled in the longitudinal direction of the pad, but across the horzontal (meaning more of the pad is touching the outside of the rotor than the smaller-radius inside surface near the hub)

What causes this? Can it be the caliper pin sticking or not being lubricated enough? How can you check for partially frozen calipers?

No matter what, I'm still going to use them as is, but if I can do something to fix it that's pretty easy, that's really what I'm looking for.

thanks

[SochBAT]

i thought i had that problem too, but maybe the caliper doesn't sit as deep for a reason?
My stock rotors had that 1/4th inch of rusty, patchy unused surface, as well as my 180 brakes.

[Giant Robot]

sounds like one of the piston is weaker than the rest in the caliper.....i'd suggest the caliper rebuild. Take apart the caliper, pop out the pistons, see if the seals and walls of the pistons have no pockets in them

[drift into a curb]

Just go with a remanufacture instead of caliper rebuild. If you hone them out incorrectly, you'll run into problems later.

Hmm.. what you could check is... take off the caliper and rotor and check the hub. Clean the hub surface with brake cleaner/acetone and sandpaper/steel brush. Make sure your torque ratings are to specification. If you want to check for a stuck caliper, you can squeeze it to see it compress. Open up the boot and check if it's still nice and greased. You can try resurfacing the rotor after you check everything but it's kinda useless without new pads because your pads are already worn into the rotor.

[TurDz]

Well, the problem could be my install techniques. We installed the rotors/pads very quickly (4 people, in like 1/2 hour) and it was dark, so I didn't get to install them as perfectly as I would want (i'm pretty anal about that). I think today I may reinstall my race pads again in preparation for my next track event in about 3 weeks.

Thanks for all the tips, I will definately clean the hub surface, clean the shims, re-grease the pins, etc.

just like on this DIY website (which IMO is very good and detailed):

http://www.motorvate.ca/mvp.php/301