So here's the story, I have a front brembo gt kit with the 13 inch rotors, calipers, brackets and braided lines on my 02 z28, and hawk/ powerslots in the rear. I just put the front kit on today and wen out and tried it. The rear brakes seem to be locking up before the fronts badly. I pulled the abs fuse just to get an idea of the proportioning of the brakes and the rears are very quick to lock up. With the abs working and you get on the brakes hard the low trac light comes on because of the rear end. I feel that I'm not getting the most from this kit because of the rear brakes locking up. Should I get a proportioning valve for the rear, but won't that make just the line pressure in the rear less and no more added to the front?? Any suggestions would be a big help, thanks, Paul. I also have kuhmo v700s all the way around, 275s up front and 315s in the rear, so with these brakes and tires I would expect more from my set up.

 

Camaroz28lt1383:
Since the only change was the front then the problem must lie there. Bleed the front again, check the line routing to be sure nothing got crimped during the install. While I don't have your calipers I do have the rotors and pads and my braking action is very strong and positive with no rear lock up at all. Any ABS or Brake warning lights on the dash display? Could the new pads and rotors been contaminated with brake fluid during the install?

 

I agree with NJ-LE... go rebleed the system, check that everything is installed correctly. Almost sounds like you've got air in the ABS system, or lines, or calipers...

 

I might try and get a mity Vac or hand bleeder to help bleed these. Is there any special way bleed the calipers with the dual bleeder screws ? Also to get the air out of the abs you just keep bleeding the system and eventually the air will bleed out? Thanks for your help. Paul

 

I used a "Mighty Vac" at the calipers and ABS unit. I never let the master cylinder reservoir get low enough to let air in the system (also never turned on the ignition to cycle the ABS system until I was done with the conversion and made sure all the fittings and lines were tight) If there's air in the ABS it should come out easily, even by gravity because it's lower than the master cylinder. I did use the vac there too because I was changing fluid type also and was worried some of the slightly heavier dot 3 would stay in the lower part of the ABS. From what I've read, if you have an ABS or Brake dash board trouble light that won't go away you're stuck with having to submit to a brake shop or dealer with a GM Tech 2 (?) tool to cycle and reset the ABS unit.
Good Luck (you should be very happy with your brakes once they're working properly)

 

Yeah thats the thing I don't have a light on at all. Pedal feel is just as good as it was before I put them on, the car stops better forsure but I'm sure there is a lot more left. The only time the low trac light comes on is when you apply them very hard, and it's from the rear brakes trying to lock up before the front.

 

I can see the "traction" light when braking hard on rough surfaces but it never feels specific to either end of the car. Not long after I did the conversion and break-in, I gave a VERY hard and quick stab on the brakes at interstate speed and got a chirp from the front tires ... original fronts never did that. Perhaps your new front pads haven't bedded in yet. If the rears are locking, I think I'd unbolt the front calipers and check to be sure the pads and hardware (anti-rattle bits and whatever shims, etc that Brembo uses) are installed as they should be. I assume the calipers slide on guide pins so check that the pins are lubed and are not nicked or bent and the calipers slide freely and all the mounting bolts are still tight. Push the pads and pistons back and observe them when remounted with some else very slowly pushing the pedal to try to see if the pistons move equally and simultaneously. All the parts you're using have excellent reputations ... could the front pads have been dragging the rotors and glazed over instead of bedding in? (Just a thought)