Problem with my Brakes.....Bad Fluid Leak!!!

[leeboy66]

The brake light on my 1977 Corvette has been on since I bought it a few weeks ago. The guy I bought it from said that the brakes needed to be bled. They felt a bit spongy, but continued to work well, although I have only driven the car once since I purchased it. Before driving it for the only the second time yesterday, I checked the brake fluid levels and found that the rear reservoir was a bit low. I added fluid and went for a cruise. The brake light remained on, but the brakes felt ok. When I got home, brake fluid was leaking pretty badly from the rear reservoir. Why do you think this is happening? I seem to have created a leak by adding more fluid. Do you think I need to replace the cover and gasket on the master cylinder? Or do you think I have a bigger problem?

 

[wishuwerehere82]

Your light is on because at one time or another you lost pressure in the system. It comes on because it senses a differential pressure in one leg of the system compared to the others.
The light will not go off until you bleed the calipers and remove the air in the system. You may also have to pump the pedal a few times to get the light to go off.

As for the leak, if it is coming from the cover, you may have overfilled the reservoir. The bladder in the gasket displaces a bit of fluid when it is in place. It should not have more than 1/8" lower than from the rear edge of the reservoir.

 

[Ludigdrums]

Hey, where in LI are you? I'm in Huntington Station and have a pressure bleeder. I'd be happy to bleed you brakes with you. Pressure bleeding is the best way to bleed Vette brakes! I've also been around the block with my fair share of brake problems.

- Jeremy

 

[leeboy66]

Jeremy, I'm in Lynbrook. My leak seems to be coming from the master cylinder which was fine until i checked the fluid level yesterday. After adding fluid, it has not stopped leaking. Do you think bleeding the brakes will really solve this problem. If so, I would like to come by and use your pressure bleeder.

 

[wishuwerehere82]

Hey Ludigdrums!

Remember when we were doing this on your Vette like 2 years ago? How time flies.:L

 

[Ludigdrums]

Do you see fluid actually leaking from the master cylinder? If so...where? If the rear reservoir is just going down, then there is probably a leak in the rear brakes somewhere (calipers, hoses, etc.) Unless it's actually leaking from the master cylinder itself.

Let me know what the deal is.

wishuwerehere82...YES, how could I forget!!! It took me a while to get my confidence back in the brakes. They work great now, except that the front left definitely clamps harder than the rest. I've tested it with a infrared temp guage, and it's always way hotter than the front right...and the rears are usually the same to each other. I've re-bled but it remains the same. It's also hard to tell if its really all a braking problem because my steering cylinder is a bit out of whack. No $$$ or time right now to get it all perfect. But it works more than well enough for now!

- Jeremy

 

[leeboy66]

It looks like it's leaking from the master cylinder itself. It seems to be coming from the cover area. At first it was just by the rear reservoir, but yesterday i saw some by the front as well. I wonder if i just need a new cover. Perhaps the gaskets are shot.

 

[JOE BYRNE]

Rubbers

Welcome to project Corvette!! Take the cover off and make sure the middle of the rubber inserts are not popping into the cylinder. If they are gently push them back up so the rubber is nice and flat. Also make sure the fluid is not right up to the very top edge

 

[GTR1999]

Welcome to Corvettes. I'm over in New HAven CT if you need any help.
Do you have a chrome cover? They are absolute junk and leak 90% of the time. If you have the stock cover then replace the gasket or the entire cover if needed.
What concern's me is this is a new car purchase from a guy who said the brakes need to be bled. BIG red flag here, vette brakes don't just need to be bled if they are working correctly. The only exception is if the car has been sitting for more then 5-6 months then the BF will absorb mositure and turn to an acid base. I would look at the whole brake system and check rotor runout to see where it's at. Should be under .003" otherwise you're going to get to know your brake system very well. Properly set up these braeks systems are very good.
If you need help let me know.

 

[leeboy66]

Thanks for the info, Gary. The cover is not chrome, but I think it is the source of my leak problem. I'll probably have to replace the gasket or the entire cover as you suggested. You are right about the red flag. I have a feeling I will be replacing the entire brake system sooner rather than later. I've been told that Corvette brakes have a history of problems.