Gravity Break Bleeding
Thread Starter
Burning Brakes
Joined: May 2010
Posts: 941
Likes: 10
Gravity Break Bleeding
I am putting a new Master Cylinder on and want to do a gravity bleed. I have search but have not found out what kind of flow I should expect to see out of the open brake bleeder. Should I see a steady flow, slow dripping flow or a fast dripping flow.
Thanks
8Valve
Thanks
8Valve
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
Bench bleed your new master cylinder before you install it as that'll cut the bleeding time to about 10%. To bench bleed it you just fill both reservoirs almost full then with two of your fingers covering the outlet ports slowly push the piston in until it bottoms while keeping your two fingers pressed firmly against the ports. Your fingers will act like check valves as fluid can be blown out but air can't be sucked back in.
Once you get it bled install it, tighten the two lines, keep the lid off, then open the right rear bleeder valves (one at a time) and wait until fluid is dripping at a steady rate like one drop per second and let it continue dripping until the fluid coming out is clear. Close off that bleeder and open the other bleeder and repeat the process. Then bleed the left rear caliper the same way then bleed both of the front calipers (only one bleeder screw on the front calipers).
Once you get all four of the calipers bled top the fluid level off in the reservoir and replace the cap. Gravity bleeding always works but it does take about 30 minutes to bleed all four calipers.
Racer
Joined: Jan 2014
Posts: 407
Likes: 14
From: Mulberry Florida
I have done mine before and had no problem. i do not know why some people have trouble doing it. There will a steady flow, you will not see it in the hose but see the bottle fill up.
Hope you can get it done.
Larry
Hope you can get it done.
Larry
Thread Starter
Burning Brakes
Joined: May 2010
Posts: 941
Likes: 10
Thanks Guys;
Very familiar with bench bleeding both brake Master Cyl's and Hydraulic Clutch Masters. I was curious on the flow rate at the bleeder.
I used to use a Mite Vac and suction bleed. But you always get some air bubbles from the air going past the bleeder threads. One of these days I am going to spend a few bucks and make my own copy of the plastic pump up tank type.
8Valve
Very familiar with bench bleeding both brake Master Cyl's and Hydraulic Clutch Masters. I was curious on the flow rate at the bleeder.
I used to use a Mite Vac and suction bleed. But you always get some air bubbles from the air going past the bleeder threads. One of these days I am going to spend a few bucks and make my own copy of the plastic pump up tank type.
8Valve
Burning Brakes
Joined: Jul 2015
Posts: 823
Likes: 57
From: Austin TX
Why would that cause a problem? When you close the bleeder, vacuum draws the remaining air out along with the last bit of fluid. I've used the Mity-Vac on all our vehicles, and it always produces a solid pedal. Just sayin'...
Racer
Joined: May 2011
Posts: 373
Likes: 6
From: Dover Delaware
Fwiw
mk's78
Mike
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Instructor
Joined: Jun 2008
Posts: 233
Likes: 9
From: Marietta Ga
Just read all the threads and FWIW I only use the gravity bleed procedure now..I have an almost brand new Motive Bleed Kit..It was used only once for a systems pressure check and I decided that the GB system worked better for me....I have the Motive kit for sale and if you decide to go that direction I'll give you a good deal...
mk's78
Mike
mk's78
Mike
Burning Brakes
Joined: Mar 2006
Posts: 829
Likes: 131
From: Spartanburg SC
I just GB my fronts this past Friday. The flow rate is dependent on how much you open the bleeder screw. My flow rate was a fast drip. I would estimate about two full turns or less on the bleed screws. I bled about a pint thru each side. Worked great.