Ok this problem started about 2 years ago when i purchased the car. i bought it from the original owner, an older coulple, through the autotrader. It had 67,000 original miles (now has 105,000). It was well taken care of, clean, everything worked properly, The owners son was a gm mechanic and had taken the car into his shop and performed all the work on it himself. I have a recepeit for every little thing that was done to the car in 14 years they had owned it. I have the original braking system in the car, front disc/ rear drums. So any how my problem started 2 weeks after i bought the car. Before i bought the car the owner had told me the fornt pads need to be changed. The two weeks i owned and drove the car before changing the pads the brakes worked good. i had a 91 rs before this with the same braking sysytem and both cars pedals felt the same and stopped evenly could lock the fronts up on both cars.


He gave me the new pads for it, bendex pads. so i changed them like i always have on front disc cars. the piston and inside of the caliper were clean except for alittle brake dust i cleaned off with brake cleaner. put the old pad back on and used a C clamp to depress the piston, pullled that off put on the new pads. lube and reinstalled everything hopped in the car pumped up the pedal untill it got firm. started the car pumped up the pedal again. it felt alittle like the pedal got firm maybe abit later than it used to. but just as firm. so i go for alittle test drive 30 feet hit the brakes the pedal feels like it did before i changed anything but instead of locking up the tires like it usually would the pedal got firm and about 1/2 -1 second later the car car finally started to stop but with only 1/3 as much force. i new somthing was wrong but i thought for what ever reason maybe they'll work if i let them wear in a bit. never made any difference. 2 years and 2 more sets of pads later same problem never changed. oh yeah i also adjusted the rears everytime i replaced the front disc.

So any how a month or 2 ago i got sick of almost dying everytime i had to make a panic stop and decided to fix it so. I've replaced in this order the master cylinder, flex hoses were replaced with earls ss lines. new rotors, with new pads. I havent changed the brake booster. it sucks the pedal in an inch when the car is started, "i'm almost positive it's good" i was thinking maybe bad calipers but it brakes evenly and pads wear evenly. i was pretty sure it was the prop valve but every one said they don't really go bad. I have no air in my lines bled them 20 time this year, i've gone through a coulpe of gallons of sysnthetic dot3/4 brake fluid, used a vacum bleeder 1/2 the times and the buddy method the other also bench bled the master cyclider prpoperly berfore intstall. the master cylider seamed to give me better rear preasure and the brake lines gave me the firmest pedal i have ever felt. if you slam on the brake as hard and as fast as you can it makes almost no difference when you push the pedal very slowly and softly. sorry if this is long as hell states the obvious. i'm just sick of people thinking that it's air, or that i shouldn't be able to lock up the fronts. i've driven about "5" 3rd gens with the same front disc/ rear drums. and all of them could lock up the fronts. I'm completly out of ideas and money. if anyone can offer any help please do. i need my brakes back. thanks
-Scott-

 

What brake pads are you using?

You might want to try stepping up to a set of Hawks.

 

It's isn't the pads. the problem is that front brakes don't engage for a second after you slam on the brakes, there's a delay, and not enough preasure, bad prop valve? To aswer your now i have "pinnacle brake technology, performance friction carbonmetallic pads," they were the best pads i could get from autozone. i've had bendex performance brake pads, the ones which were originally on the car when i bought it and worked great, then i replaced them with the same pads and everything went to hell after that.

 

That is a real baffling problem if you've tried changing all those parts.

If you're running out of money, swapping the front calipers is really cheap since they've been used forever by GM.

They're $11 + 10 core at Autozone. I'd say go to the junkyard and pull a pair just to test, but with them being that cheap, just do it right the first time.

Do you get air out everytime you bleed the brakes? Is your car leaking anything? One thing that comes to mind is that you have a small hole in one of the hard lines and it's causing it to leak fluid and it takes it a little while to build pressure.

You've done what I would've done so far.

 

It does sound like a fluid leak, i kinnda thought so too. but it's never dripped any fluid or consumed any brakefluid. it's gotta be the calipers or the prop valve. maybe when i changed the pads that first time when i depressed the pistons back into the calipers into pushed some kinda of a blockage into a small opening in the prop valve. i think i'm gonna go down to the bone yard this weekend and pull of a set of calipers and a prop. I mean what else could it possibbly be? after every install master cylinder, brakelines, i bled the sytem 2 times to get all the air out. but air isn't working it's way back in. when i drive it for a week or two and bleed the lines, like i've been doing lately it's always buble free. Thank you for responding to my post Nape, any more advice you or any one has to offer would be apprciated. thanks, Scott