Low brake pedal 72 stingray

[Gary L.]

hAD BAD MASTER CYLINDER WHICH AFTER I REPLACED IT, I HAVE A LOW BRAKE PEDAL. iT HAS GREAT PEDAL UNTIL THE ENGINE IS STARTED. IT DROP TO ABOUT 2 INCHES FROM THE FLOOR. I HAVE CHECKED FOR LEAKS, CHECKED PADS, CHECKED BOOSTER, BLED, BLED, BLED BLED, AND BLED BRAKES. nO AIR IN SYSTEM. BRAKES SEEM OK, BUT I DON'T UNDERSTAND WHY THE PEDAL IS SO LOW. TALKED WITH NUMEROUS PEOPLE AND MECHANICS AND THERE SEEMS TO BE A LOT OF THIS GOING AROUND ON THE CARS. ANY IDEAS? HAD PEDAL ON FLOOR WITH LIGHT ON WHEN I GOT IT. THAT WAS MASTER CYLINDER. I JACKED UP THE REAR OF THE CAR TO BLEED EXTERNAL AND INTERNAL BLEEDERS PER CHILTON MANUAL. NEVER GOT ANY AIR. WHAT IS THE SECRET?

[Edward J.]

Re: Low brake pedal 72 stingray

Gary, Bleeding the air out a corvette disc brake system can be a pain. The best way to remove air I find is to just take the top off master cylinder and crack the bleeders one at a time since the rear calipers have a inboard and outboard bleeder ,start with the r/rear inboard and be patient take a drop light and just keep I eye on the bleeder you'll see the air bubbles start to come and when theres a flow of fluid go to the out board bleeder next and so on. Ed

[Michael W.]

Re: Low brake pedal 72 stingray

The master cylinder needs to be bench bled prior to attaching the brake lines. Not sure if you did that or not.

[Terry M.]

Re: Low brake pedal 72 stingray

Gary,

It is not unheard of for new parts to be defective right out of the box, so do not assUme that the "new" master cylinder works perfectly. Do eliminate other possibilities before changing it again. I also rap the brake calipers with a dead blow hammer -- rubber mallet will also work if you don't have the dead blow -- a couple of times to be sure there are no air bubbles clinging to the walls of the caliper.

[Gary L.]

Re: Low brake pedal 72 stingray

I did use the gravity bleed process along with the wife pumping the pedal, & vacuum. Gravity bled again after test drive along with taping on calipers. Guess this is what it is. Other people i checked with say they cannot get their other shoe under the pedal when it is all the way down. Noticed the floor board goes almost straight up, so this may be how it was designed. I am use to there being a higher pedal from the floor on other cars. Thanks for everyone's input.