Eyedeas

I bought some used XP8s for the rear that had a ton of meat left. This is how they ended up bedding. What the heck do I do? Replace the pads? Replace the rotors? For what it's worth, the front XP10s bedded in perfectly. Help please!

gsflyer2011

Used pads and used rotors i gather? Naturally one cannot expect them to bed in perfectly as neither are straight and with some taper. I am actually surprised that the fronts bedded perfectly. That is more unusual. This is very normal. Did you do break in? Just let it go, with more usage they will get evened out. I really would not loose any sleep over that at all.

Eyedeas

Brand new rotors all around. The front pads were new, and they bed together evenly. The rear pads were used but had a lot of life left. I'm just worried about the rear since they're not making full contact with the rotor. Part still has cross hatching and the other part is worn.

gsflyer2011

Ahh! Ok thanks. Then i chuck the used pads asap and put new ones in before the old pads cause more damage.

Eyedeas

I'm wondering if I could just leave them and they'll wear themselves flat. It's either that or replace. Idk. I'm on a time crunch otherwise I'd say just to replace.

Adam@Amp'dAutosport.com

Here is my take. First off once a carbotech pad is bedded it does not need to be bedded again. So, what you were doing is actually using up pad material. I would check the rears and make sure everything is lubed and siding freely in the caliper with that being said if all is good I would not hesitate to use them. What bedding process did you use? If the xp8 compound is smooth and very shinny you glazed them . If glazed than I would chuck them. What's your time frame?

Eyedeas

I was transferring pad material to the new rotor, is that not the purpose of bedding? I also had brand new pads and rotors up front, so I had to bed those at the very least. My bedding process was going around the block to get an initial layer on there (didn't realize how necessary this was until I first left the driveway...pads had NO bite), then after that I took it out the next day and did stops from about 60-70 down to 20 ish and did that for about 10-15 minutes until they started to feel a little squishy/fade. Then I drove easy on the brakes for about 20-30 minutes at speed to let them cool.

My timeframe is until Thursday. My first HPDE is Thursday AM.

Adam@Amp'dAutosport.com

Yes, you should lay a transfer layer down on new rotors. But the xp8 would have done that with out bedding them since they where bedded before. What is your bite like now?

And no that is not the purpose of bedding pads Carbotech pads need to be bed to release the gasses in the binding material of the friction compound. This is why I always recommend pre bed XP series so, you can take a few laps easy and lay the material down and go no need to bed. You should actually bed new rotors with old pads so that layer is down there before this is assuming you are using the same brake pad manufacture.

windyC6

Using used brake parts on a old DD or beater is one thing, but heres a good rule of thumb for a high performance car such as our Corvettes. Used rotors.....never. Used pads....never.......

Adam@Amp'dAutosport.com

Eyedeas

Yeah apparently that's a no no. New rotors, pads with barely any use. Figured no problem. It was given to me by a good friend who has a lot of experience on the track with more than a few cars. Figured it would be fine. You live and learn though. The question is now to leave it or replace. ��

Adam@Amp'dAutosport.com

Maine issue is using used pads with new rotors. You may be ok but I would like to see the condition of the pad.

jft69z

You're going to a HPDE with brakes that appear to be making poor/uneven contact? The answer would seem pretty clear....replace.

Adam@Amp'dAutosport.com

Material. What's your bite like now?

Adam@Amp'dAutosport.com

unless there was some install issue.

gsflyer2011

And that is my life ling motto too, you do not mix old and new on any assembly that will be working together ever and i only made one exception only once, when i switched to carbotech 1521 s at 2000 miles when my GS was new. The OEMS had to go and the rotors were too new to go buy a new set but it took a long time to get them bedded together without any shimmy and noise thank god. The original pads had eaten up the rotors so bad at that low miles but bobcats cleaned that up a lot.

jft69z

It's not like it's some beater from the northeast where salt & corrosion have left rust or high spots on the caliper mounting surface that would cause the pad to sit wrong. Still worth checking that those surfaces are clean & flat without any debris. Checking that is just a standard part of ANY brake job though.

Just like not using a big C-Clamp or pad spreader and just pushing the pistons back, thus forcing all the sediment & crap back into your nice expensive ABS unit. (open bleeders & drain fluid into container while pushing pistons back to help prevent this.) Or cleaning hub flange surfaces to make sure the rotor sits true, or checking the rotor run-out to make sure it is in spec...etc.

Eyedeas

I was originally adviced that it would even out with some heat and use. So forgive me for asking the question, I'm on a time crunch now so I wanted to at least ask and double check.

Eyedeas

Great. Feels good, had no idea it looked so terrible until after I got home. Everything felt normal and bite is solid.

jft69z

Completely understandable...