Pressure Bleeding Pressure
Thread Starter
Racer
Joined: Nov 2019
Posts: 336
Likes: 173
From: Canadian living in southern France
Pressure Bleeding Pressure
After replacing all the brake flex hoses on my '76, and then trying to bleed the brakes five different ways, (none of which worked), I have ordered a Motive Power bleeding kit from Summit, and should have it Tuesday.
The brake system on these cars is very different from other American cars, and I'm not expecting there to be guidelines just for Corvettes.
My one question is : Does there seem to be an optimum pressure level, at which the air is flushed out most effectively?
Thanks in advance, from the south of France.
The brake system on these cars is very different from other American cars, and I'm not expecting there to be guidelines just for Corvettes.
My one question is : Does there seem to be an optimum pressure level, at which the air is flushed out most effectively?
Thanks in advance, from the south of France.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
Likes: 2,810
From: Cool Northern Michigan
I have found 12-15 lbs is all that is needed. It doesn't take much. Over those specs just causes unwanted leaks at the MC lid.
By pouring two bottles of Dot3 in the pressure tank, pumping it up to 15 bs, you should be able to do all six bleeders. As you near completion of the process, you should back-off the pressure so as not to spray your fender and engine bay when disconnecting. The last bleeder, left / front is a good place to cease air pressure. When done, the tank / hose should be rinsed with denatured alcohol.
You may also consider some type of shut-off valve in the clear hose. Also if the hose is extra long, the tank can stay down on the floor of the garage. Less chance of spraying something you shouldn't.
The MC lid adaptor that comes with the tank is disappointing to say the least for old style systems. Take a look at my profile > photo album > pressure bleeding for a idea how to make your own MC lid for about $15.
By pouring two bottles of Dot3 in the pressure tank, pumping it up to 15 bs, you should be able to do all six bleeders. As you near completion of the process, you should back-off the pressure so as not to spray your fender and engine bay when disconnecting. The last bleeder, left / front is a good place to cease air pressure. When done, the tank / hose should be rinsed with denatured alcohol.
You may also consider some type of shut-off valve in the clear hose. Also if the hose is extra long, the tank can stay down on the floor of the garage. Less chance of spraying something you shouldn't.
The MC lid adaptor that comes with the tank is disappointing to say the least for old style systems. Take a look at my profile > photo album > pressure bleeding for a idea how to make your own MC lid for about $15.
Last edited by HeadsU.P.; Aug 17, 2020 at 07:15 PM.
Le Mans Master
Joined: Mar 2004
Posts: 7,470
Likes: 1,490
From: Little Rock AR
My memory seems to be that you want to assemble it dry and pressurize it once to verify that you have it sealed. Pump it up to a little over 5 PSIG and see if it holds. If it stays pressurized, release the pressure by unscrewing the top and then you can add the fluid to the bleeder and pump it back up to 5 PSIG. Continue with bleeding the calipers beginning with the wheel furthest away from the master cylinder. Do the inner screw first and try to get the bubbles out then do the outer screw after that before moving on to the next caliper.
