scoob5017

I have a 1972 with a complete wildwood brake system 1 in master with 6 piston front 4 piston rear gravity bleed them then did the old pump and release the petcock and then they just go to the floor. I am going to pull the master cylinder and bench bleed it again then go around caliper by caliper. so my question is do I have a prop valve or a distribution block in her . I have read that the prop valve can cause all types of headaches. She has the brake warning light switch in the distribution block just not sure and would like a definitive answer before I pull the rest of my hair out. Thanks in advance

NeverTooOld

The C3's have a distribution block with a centering valve in it that turns the BRAKE light on if it senses there is a pressure differential between the front and rear brakes. If your BRAKE light is staying on stomp HARD on the brake pedal a few times to reset the pressure differential valve.

JayRay

Check your caliper thickness and replace as necessary.

cagotzmann

Before bench bleeding try this. Works every time for me. Saves many hours to get the last bit of air out of the master cylinder.

https://www.corvetteforum.com/forums...-cylinder.html

https://www.corvetteforum.com/forums...gy-brakes.html

carriljc

I recommend you use a pressure bleeder. I installed the same 6-piston forward, and 4-piston aft,brakes over 5 years ago and I have NOT had to rebleed them since.

I gather that you replaced the hoses at each corner at the same time?

Nevertheless, consider getting a pressure bleeder, or if you're in a hurry, then just fabricate one from a garden sprayer---it's cheap and easy and you can get the thing at your local hardware store. I would actually try this before removing the master cylinder.....unless you have a reason to doubt the master cylinder. Either way, it's good to have a pressure bleeder anyway.

More info here: https://www.corvetteforum.com/forums...post1581454605

ctmccloskey

Hello there,
I have a 1968 L-71 car and have done lots of work on my car's brake system in 27 years of ownership. I am still using the stock style calipers with O-Ring pistons and they are still working okay.

Yes, they can be a pain in the butt to bleed if you don't have the right tools. I drained my system right after buying the car because I was not sure just how old the fluid in the system was. I rebuilt the calipers and tried bleeding it like I had always done. I pumped and pumped the pedal with little containers at the wheels. I even tried the one way valve "Speed Bleeders" which were a giant improvement but still a lot of work.

After a year or two I ended up buying one of the Phoenix Speed Bleeding systems. This system lets you push the fluid from the wheel back to the master cylinder. This system makes it very simple to do and it works on any vehicle I have.

When I tried silicone based brake fluid I really appreciated the ease of flushing out the system. I had to flush the lines and refill the entire system several times.

My C4 has the ABS system behind the drivers seat where the C3 battery lives. That is a real pain if you try bleeding it the normal way as there are several brake lines that have loops in them causing the air to stop all movement of fluid. The Phoenix systems has no problem pushing the air upwards towards the master cylinder.

Good Luck and may your Brakes always be ready for anything!