breathment

I was doing some reading about the rear brake proportioning mod. and the first post seemed to have alot of praise for it. but the second 'update' post seemed to have some disagreement coming from Larry and Andy who brought up some good points. i dont' want my rear brakes locking up in an emergency stop. but since my front brakes never even come close to locking up i am starting to wonder if maybe my proportioning valve or m\c is in need of replacement, as i believe Andy was suggesting to everyone. but i have been doing some reading and since some people can lock up their front brakes and i can't even come close and i can get my parents 4000 lb jeep fully loaded to stop about 50% quicker then my car (no lie), then i think i might have some more problems.

the calipers\pads all the way around are new. the rear calipers rebuilt with the GM rebuild, and new e-brake cables, and the e-brake is used everyday.. i have NEVER gotten the front brakes to lock up, (except in rain). and i can be driving at any speed and pull the e-brake and the rear wont lock.

so i am thinking about getting a new m\c and prop. valve.. but i want to know if this is normal for the stock brakes to suck this bad or if mine are just special.

MdFormula350

sorry i was bored at work.

i just read the title

anyway my front brakes lock up before the rears do, my rear brakes are also pretty shot from all the burnouts...

my 88 iroc-z when i had to stop real quick to avoid an accident (still hit the car) cocked sideways, the rear locked up and not the front.

i did the spacer thing in my 88 formula and finally got the fronts to lock up before the rear did, made my car alot safer then my first car.

for some reason my 91 formula has no problem locking the fronts first.

No4NJunk

edited!!

Back to topic....Breath, I can barely lock them up. My problem is that the headers run very close to the brake lines and is probably expanding the fluid and causing air bubbles. But nonetheless, I'm doing a complete brake tune up soon so It won't be bad for long. The car brakes very good though and stops on a dime.

MdFormula350

heating up the brake fluid probably isnt a good thing, probably some sort of insulated wrap / tape would work well to protect brake lines from to much heat.

No4NJunk

Maybe but as close as they are (almost touching) insulated wrap can only do so much. Those headers get up to 1200 degrees +!! I'm probably going to replace all the lines in the front split anyway.

Randy82WS7

make sure rear brake shoes are adjusted out and are self adjusting and not frozen adjusters, is a common problem and would help cause front lock up

HamSpiced

i had this problem with the brake lines getting hot. i was told by a mechanic friend to wrap the brake lines with aluminum foil (he claimed it was an old trick) and it is supposed to deflect heat. works for me so far.

laiky

if you are talking about the interference on the drivers side under the header ( i have slp 1 3/4's) you can bend them down, that helps alot, i had put my engine in and had the header tube touching ( HPC Coated) and i lost my brakes on a high speed run. Since moving the line i have not had any trouble.

Have you tried locking the fronts after the brakes were hot? Semi mets need some heat to work good. Did you resurface your rotors at the last pad change??

waltersb

The only time I think I've ever locked my breaks up was in the wet, and I'm pretty sure I locked the all up..

I drive it fairly hard sometimes, don't think I've ever had to lock them up to stop

Clint E.

On my 88' IROC with 4 wheel disc, when I first bought the car the brakes worked excellent, but they wore out so I had to change them, I used brand new rotors AC/Delco carbon metalics and they sucked I couldn't even lock the fronts up. Last year I replaced the front calipers totally flushed the fluid out of the old system and put on some cheap jobber pads. They now work alot better, not great mind you, but at least I can lock up the front tires. I think that carbon metallic pads run too cold in a camaro and thats part of the problem. Also look at the brake fluid it is supposed to be clear not brown or balck like mine was.

nikh23

sorry if i'm wrong, but wouldn't locking the brakes up be bad, i mean that is why they invented ABS right?

No4NJunk

ABS prevents lock up by sensing the air pockets in the suround plate on the hub. When the brakes are put on and it senses no air movement is pulsates the brakes to allow for a very mild "slip" so that lock up doesn't occur.
We don't have this technology in our cars. The reason we want ours to lock up is because we can control the lock up ourselves by pumping the brakes. If your brakes don't lock up then thats a good indication that something is wrong and your stopping distance will suffer horribly.

nikh23

gotcha, sorry about the stupid question i wasn't familiar with how ABS actually worked, thanks!

No4NJunk

The only stupid questions are ones unasked!

Clint E.

Doesnt ABS work with magnetic wheel pulse sensors not air?

laiky

There is a toothed reluctor that rotates with each wheel, the sensor is magnetic, as each tooth passes the sensor it creates a small electrical pulse. This pulse rate is used to compare wheel speeds. if one or more wheels stops suddenly the abs computer can see the change in pulse rate from that wheel and then modulate line pressure for that wheel. It has nothing to do with air pockets.

No4NJunk

aah! Thats what I get for listening to the wrong people. I knew it sensed wheel speed somehow and for some reason I was thinking the sensor rotors thickness had to do with air speeds. Now that i think about it that wouldn't work right though. oh well. I got half of it right . Guess I should be asking the questions.