This is in regards to the '89 IROC in the sig...

Actually, the calipers didn't work before *or* after I rebuilt them. (see this post for a picture of how my rotors are wearing) When I say they won't work, I mean that I can have the car in drive with the emergency brake on, and the car still creeps (even when I don't give it any gas). Also, I tried propping up the rear on jackstands and ran the engine. With the transmission in drive and the brakes applied, the rear wheels only barely slowed down--and this was with the benefit of the power brake booster.

I ordered the AC/Delco rebuild kits and spent several hours yesterday rebuilding both calipers. I couldn't tell that any thing was visually worn very much when I tore them down, but I had the kits so I went ahead and put all new seals in. I did notice that the pistons were very tight in their bores, but the bores were clean and straight. So I figured that that's how they're supposed to be (tight).

I went to test-drive it, and the stopping power is still bad. And the rear rotors still look the same--virtually no wear. I have bled the heck out of the lines, too.

Also, I have been driving the car for ~550 miles with the brakes like this, and I haven't seen any improvement (so I doubt it's a simple pad alignment issue or the pads would have worn-in by now).

Any ideas what could be causing the problem here?

Thanks

 

I have the samwe problem except the pads are only a inch or so wide so therefore it does not cover the entire rotor. Thats why you are only seeing half the rotor wearing. At least that is whats going on with my car.

 

Is it normal, then, that the brakes can't even hold the rear wheels when elevated and in gear? It seems like they ought to at least be able to hold that...

 

yup... it's normal. and no the rear brakes cannot keep the wheels from turning while in the air.


i had the exact same trouble as you. i also rebuilt my calipers trying to fix the prob and bled the **** out of my lines(many quarts later). do you have a spongy or low pedal? i was getting real mad and was ready to get a 4th gen rear. i took one caliper completely off, leaving the hydralic line attached, and pressed the brake pedal more than a few times. i noted how the piston assembly worked. i was like wtf? they are working. i then moved to the next wheel and did the same procedure. after a test drive i was aww *** same ****. a few days later the brakes began working much better. they have been working good since i did that last month. make sure your ebrake is adjusted properly. mine was constantly pulling on a caliper. that may have been my problem all along . good luck.

 

mystikkal_69: Mabye I actually do have a minor alignment issue, then?

But, the e-brake adjustment shouldn't affect normal braking, should it?

Thanks for the response...

 

i wouldn't think so, but my brakes are working so.... i dunno

 

I dunno about that... my PBRs work pretty damn good, the parking (NOT "emergency") brake will hold the car on a real steep hill going forward, and a fairly steep one even in reverse.

Sounds to me like you have something else wrong with your brake system; master cyl, prop valve, rubber lines, etc. If the calipers didn't use to work, and you fixed them and they still don't work, then the problem must lie elsewhere, assuming you fixed them correctly.

Just being logical, sorry. I have no brain so I'm pretty dumb, so that's the best I can manage.

 

Are you standing on the gas when you do this? My brakes hold the rears stopped just fine. Something isn't right here. And I don't see why swapping to another rear with the same PBR brakes would do anything different? Point is something isn't right. If you havent' already, look into your prop valve or master cylinder. You seem to be getting fluid at all the corners so the lines aren't your problem.

Ed

 

ok i re-checked since they work now & at idle they can, but above idle they cannot(ie 1000rpm wheels turn real slow). anyways they work good now . they whole system new with acdelco components, exception being the rear calipers and flex lines(non-acdelco). woo hoo. i did spirted stops last night


p.s. i will be posting about a slight problem with wheel lock up on the drivers side