Gravity Brake Bleeding
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Melting Slicks
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From: Englewood FL
Gravity Brake Bleeding
When you gravity brake bleed, can all the brake bleeders be opened at the same time, as long as the master cylinder is keep full? Or will air be introduced, so only one bleeder can be opened, starting at the inner right rear caliper?
1967 Pedal Car Champion
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From: US-PNW
Yes, you can open all at once with no problems. FYI, the front and back are actually two separate systems. You'll see fluid appear from closest to master to farthest - opposite from the usual sequence advice.
PS - I do agree with Jebbysan (below) that all open at once can be stressful. Maybe front and back on one side first, then the other so's you're not running around the car.
PS - I do agree with Jebbysan (below) that all open at once can be stressful. Maybe front and back on one side first, then the other so's you're not running around the car.
Last edited by barkingrats; Apr 7, 2021 at 09:29 AM.
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I would also do a pedal pressure bleed after the gravity bleed. I did as there was still some air in the system after a gravity bleed.
Le Mans Master
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From: Loveland
If you are just replacing the fluid in your system, gravity bleed is fine. If you are trying to get air trapped in your system out,,,,,, not so much.
Last edited by kodpkd; Apr 9, 2021 at 03:18 PM.
Thread Starter
Melting Slicks
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From: Englewood FL
Team Owner
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Not sure how 'gravity bleeding' eliminates the trapped air at the top of each caliper bore cavity. I still like to have some pressure on the fluid to make it circulate well and get rid of almost all air in the system. A pressure-bleeder system would be ideal for a one-person brake bleed job.
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have you tried a pressure bleeder, really fast and no stress. Just dont pressurize it too high.
Thread Starter
Melting Slicks
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From: Englewood FL
Le Mans Master
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From: Cool Northern Michigan
Love those Motive tanks. Have one myself. They are great for forcing contaminated DOT3 and bubbles out.
However, in your case, you are just performing a refresh flush.
Considering the cost of the tool and headache of manufacturing a lid for the MC, you wiould be better off just sticking to gravity flush.
Not likely any air in system anyway.
However, in your case, you are just performing a refresh flush.
Considering the cost of the tool and headache of manufacturing a lid for the MC, you wiould be better off just sticking to gravity flush.
Not likely any air in system anyway.
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From: los altos hills california
Melting Slicks
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The first bleed is easy, open the bleeder until fluid reaches the end of the tube, close bleeder, remove tube to let air into the tube and reconnected, open bleeder push fluid unit the air reaches the end of the tube again.
If you wanted to do the math you could calculate the volume of fluid in the length of the tube vs the fluid capacity of the MC.
During initial testing I found with my setup, rear brakes are about 3-4 full bleeds of a 6 ft clear tubing, and front brakes are about 5-6 full bleeds.
after you hit the limit, add fluid. I set the air pressure to 20-25 PSI and does a great job removing air in commonly trapped area's.
If the MC goes dry no big problem do this. When I installed the MC I did bench bleed, but this doesn't get all the air. This has never failed to get the last bit of air from the MC.
Get the last bit of air out from the brake master cylinder. - CorvetteForum - Chevrolet Corvette Forum Discussion
Last edited by cagotzmann; Apr 8, 2021 at 07:40 PM.
Le Mans Master
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From: Loveland
I have been pushing this method for a few months. Raising the rear up high. I think people think we are nuts. After more than a year I finally got a hard pedal doing this,,,,, even after bench bleeding the MC you get more air out.
Melting Slicks
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From: PHX AZ
Mark very timely!
I just did the complete brake job in the CE. Frankly, I thought that 'gravity bleeding' was a 'myth'. I even went so far as to build a 5 psi pressure bleeding rig.
It sits UNUSED!
See, time was on my side; I religiously followed the service manual's 'Bleed Sequence'...'cept I gravity bled them. For the rears I made a 'Y' pipe bleeder. Took a leisurely few hours.
DAMN! if it didn't work! ROCK HARD PEDAL!
Do not in any circumstance let the M/C suck air.
DOT 4 only.
Good luck!
UNKAHAL
I just did the complete brake job in the CE. Frankly, I thought that 'gravity bleeding' was a 'myth'. I even went so far as to build a 5 psi pressure bleeding rig.
It sits UNUSED!
See, time was on my side; I religiously followed the service manual's 'Bleed Sequence'...'cept I gravity bled them. For the rears I made a 'Y' pipe bleeder. Took a leisurely few hours.
DAMN! if it didn't work! ROCK HARD PEDAL!
Do not in any circumstance let the M/C suck air.
DOT 4 only.
Good luck!
UNKAHAL