I bought a 90 Corvette from a private party. It ran fin but the pedal was a little hard. Decided oh well, and just drove it. Fluid was low but figured it would wait until the weekend. I took and ordered the rubbers for the lids of the master cylinder. Replaced them, and said I would put fluid in on Friday, as I wanted to check pads anyway. Hmm they were low, so I went and bought front and rear pads, as I prefered to put a fresh set on, front and rear, so I had an idea how they were wearing. I came home, and they sat on my tool box that evening. I said I would run to the store, and the pedal was as always all the way there. When I came out of the store and was on my way home, the pedal went soft and to the floor, but I made it the couple of blocks home. I checked and the fluid did not look any different. I added fluid and pumped the pedal. Seemed to feel ok, but still real low. I jacked the car up, took the front tires off and proceded to do the pads. The left front brake was dragging. I did the pad spreader to push the pistons back in the caliper, and everything went real smooth other than when I pumped the pedal to get ready to bleed the brakes, and the pedal was hard as a rock. I pumped it several times, and then said I must have something trapped someplace. I had the wife pump the pedal about 5 hard fast times, and then cracked the bleeder on the left front. Very little flow if much, mostly moist not flow. Hmmm sounded bad, so I went and moved up the line. Tried at the rubber hose and still just a trickle of fluid. Hmm tired the same at the master and I do not have hardly any flow out of the front of the master cylinder. Is there just a trapped bubble not letting the fluid push the air out, or is it time to take the master apart and rebuild her. Can I even buy a rebuild kit for this model? Am I stuck with getting a new master, and then if that is the case, what is a good upgrade from stock, as in the very near future I plan to upgrade to Brembo calipers, and cross drilled rotors anyway.

Looking for sugestions if anyone has any.

 

ok... I will say this... you are a moron. Driving around on a known low brake reservoir is just plain ****ing stupid.

I feel better now.

Start the car, that will help bleed the brakes, cause now the booster will have some love in it. The booster won't last forever without any engine vacuum. Otherwise, you need weightlifter calves to pump up the system.

There is a chance you need to rebleed the master... but what I would do now is loosen the bleeders and let gravity do it's thing.

you cannot rebuild these masters.

a hard pedal is a bad booster, a soft pedal is a bad master.

Brembos? damn, you have money...

 

First I only drove it a few blocks and by low pedal it was lower than the suburban but still felt pretty good.

I know it was stupid but thought I could get it home.

The pedal is hard but when I cracked the rear line on the master is bled down a tiny bit, and then I sealed it up and when pumping it up, it felt pretty normal. Well except it still has not front braked, I am going to try to gravity bleed the front brakes and see if I can get something to move. If not, I will just get a new master, and go from there. If that does not work, then I guess it is going to get an upgraded brake system. Just hate to put that kind of cash in a street car that is used for driving back and forth to work, and might see an autocross once or twice a year, and is going to make 1 trip to willow springs raceway each year for a fun run.

 

if you want to upgrade, check out the C5 brake conversions. Much nicer than C4, and a **** load cheaper than the Brembo (think $2500.00).

 

Hey there, Mark,

Your Hoosier buddy here.

If you decide a booster is what you need rather than an MC, I've got one of those, too.

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as I said, a soft pedal is a bad master, a hard pedal is a bad booster.

with limited flow... I would wonder if both weren't toast. sometimes, the master will leak fluid into the booster, that's really bad.

 

Indianavette, check your PM I sent one asking how much.

 

You do not want hard fast pumps! You want her to pump more slowly, and as far as pedal will go to floor. Then release pedal slowly with foot always in contact with pad.....like this Puuuuuuuuuump, relllllllllllllease, puuuuuuuuuump, relllllllllllllllease......

 

You may want to try to get a set of speed bleeders while your working on it. The make bleeding your brakes a breeze.