dgc5769

Hi Everyone,

My 92 has always braked poorly. Feels like the brakes are glazed or there is not enough brake pressure. I've replaced the pads and rotors, the hoses, the master cylinder and the vacuum booster. The local shop checked my brake pressure and said that it was normal. The only thing I can think of now is that possibly when the car is in motion, the computer/ABS is not valving enough pressure to the calipers. Does anyone have any idea what could be causing this?

Flame Red

Just wondering if you properly bleed all the brake lines and put in fresh DOT 4 fluid?

jaa1992

j55 or jl9 brakes?
What kind of fluid did you use?
Did you bench bleed the master?

I did the same thing to my 92 and she hauls down pretty good from 110+ to 50. So much so I'm still overbraking even after a year.

You may need to look at the hard lines, could be a pinched line, corrosion, etc.

dgc5769

Hi FlameRed,

I had the local brake shop bleed the whole system when I took it in to check the hydraulic pressure. Not sure what kind of fluid they used. The pedal is plenty stiff, tho

dgc5769

Hey jaa1992,

I think I've got the smaller brakes...11" vs 12" ?? Anyway, I didn't bench bleed the master cylinder, but the pedal is rock solid. Just takes a lot of leg to stop the car. Feels a lot like only the back brakes are really working. The proportioning valve is in the master cylinder though, and replacing that didn't make a difference. I'm really stumped.

socalman

I'd say that's the 12" brakes. My 92 felt the same, did all the same- new rotors, pads, stainless lines. Installed C5 front brakes and now it stops like it's suppose to. If the car is new to you, it's just how an 18 yr old Vette felt with the non optioned bigger brakes.

http://forums.corvetteforum.com/c4-t...done-pics.html

Cyclonite

What kind of pads? I put new NAPA pads on my 91 and I feel like I have to put my foot through the floor just to get it to slow down some, and put Hawk HPS on my 92; that one feels like my brain is coming out of my eyeballs when I hit the whoa-pedal.

If everything else (mechanically) is in proper working order, maybe it's just the peroformance of the pads.

jaa1992

That would be the next thing to look at.
I had an 88 many moons ago that still didn't have ok brakes until I put a set of PFZ pads. The brakes were bad with any parts store pads. Don't think you can get the PFZ pads any more, go with the Hawk HPS or Carbotech street pads.

jstkrsn

I changed to the J55 calipers with 13" slotted/drilled rotors with steel hoses. Have ceramic pads and synthetic fluid. Car stops on a dime now.

Joe C

i have the exact same thing going on in my 90. i have new pads, master cylinder, S/S brake lines, etc. i have to stand on this thing, and it still feels like i don't have 100% braking power. i'd hate to be in a panic-stop situation in this thing. i have bled the system four times, and i'm fairly certain, i don't have any air in the system. also, there is no way in hell i can lock the brakes up and get the ABS to engage. i'm suspecting glazed rotors, and i the pads i bought were cheapo autozones - it was a temporary set of pads. as we speak, i'm installing new rotors, and powerstop's evolution ceramics, so we'll see how that works. i have new rotors the powerstop ceramics on my 05 silverado, and she'll stop on a dime (and give you a nickel change). if i'm still having issues, it's off to the shop for a power bleed and a diagnostic check on the ABS system. i once read something about clearing some codes or something on the ABS, but i have to admit, i'm somewhat clueless, and i can't seem to find anything in the FSM. dgc5769 - keep me informed on your brake system progress and any fixes that solves the problem. sounds like we have the exact braking issues...

vette079

Never heard of glazed rotors, glazed pads OTOH (but that´s probably what you meant).
What many people have bad luck with, is the break in of new pads.
Allways take it slow in the beginning, smooth pedal movement, and not too long on the pedal, better with short smooth intervals.

Once "broke in", try to do a "panic" stop on a closed road, so the ABS kicks in, preferrably on a dry road, so the system has to work really hard.
Do that once or twice and see if you feel any difference later on.

Joe C

glazing most often occurs in pads but glazing can also occur in rotors. its usually caused from prolong periods of excessive heat. the surface of a glazed rotors almost has a slick, polished look and feel.

i'll be finishing my brakes this AM, so i'll post the results with new pads and rotors shortly...

BTW, here's a little something i found on-line -

http://www.ehow.com/how_4421355_clea...ke-rotors.html

GKK

The 12" JL9 brakes will stop fine if working properly.

I'd have the ABS system checked for codes by a shop with the proper ABS test equipment.

12" brakes should stop just as well as the 13" brake system but, will begin to fade sooner.

Sidney004

Its the pads, try the Hawk HPS or HP+ .

socalman

If there was a problem with the ABS system, going to a 13" brake system wouldn't have changed anythings. The 13 vs the 12 is like night and day. No way 12" will ever work as well as 13. (less effort, bigger rotor, bigger pistons, bigger pads).

ddahlgren

J55 uses the same pads as a 12 inch rotor. I think mine are glazed for whatever reason and will remove the pads and scuff them and the rotors with some 220 paper and see what happens. I can not set off the abs on a dry road. I have hps pads and new rotors all the way around.

vette079

OK, still never heard of it before, but who am I, I just thought they would become warped when getting too hot.

I learn something everyday like most of us.

Lrod

I read that the ABS computer can retain codes that need to be cleared??? I did all of the above, Hawk pads, SS brake hoses, bleeding & a DRP prop. valve spring, brakes very good!

socalman

I didn't know that. Is the caliper the same? If so, then I should clarify that there is a huge difference between the C4 and C5 brakes.

Joe C

just finished the brakes on my 90 - new rotors and ceramic pads. test drove the thing to break in the pads, and i can say there is a great improvement in my car braking performance. i guess i can chalk it up to glazed rotors and cheap pads. i'm still going to take it in to the shop and do a power bleed and check the ABS system and clear the codes if any. as of right now, 110% improvement!