Brake Bleeding Method

2 posts in this topic


I recently reconditioned my MATCO brake set up on my MK4. 

I have double pucks. 

The right side was blead the way I usually do it. From the bleed valve I attached my oil pumper can. Open the bleed valve and pump like mad till the reservour fills up Then empty the reservour and repeat until all the bubbles are gone.

Worked just fine on the right brake but we couldn't get the bubbles seen between the two pucks to move out of position. We tried to have someone push on the brake and then we'd open the bleed valve. This didn't work. So I bought the vaccum bleeder from Harbor Freight And tried to suck the fluid up to the reservour with a supply of hyd fluid at the bleed valve. No luck. 

I had given up for the day when a friend said he'd like to try his method. He has hyd fluid in a small pump up garden sprayer. He hooked it to the bleed valve,piuuiumped up some pressure, pressed the trigger and I stood by at the reservour to catch the overflow. This method moves the fluid through the system that it easily moved the bubbles out of the system. I do NOT like working on brakes.

Final results: I can run the Jabiru up to 2800 RPM and holding the brakes can lift the tail off the ground. So now I finally have sufficient brakes on my Avid, but not so good to cause a nose-over in a panic.

John M


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I use an old medical vacuum pump. I hook the hose from the pump over the bleeder fitting and turn it on. I then crack open the bleeder an 1/8 to 1/4 turn. Then I constantly keep adding fluid to the reservoir to replace the fluid getting sucked through the lines. If I let it get too low it sucks in air and I have to start over. After a cup full of fluid shows up  in the vacuum pump's jar I shut the bleeder while the pump is running. If I open the bleeder too far it sucks in air around the threads on the bleeder fitting. The vacuum pump is just like my diaphragm air brush compressor; the only difference is the inlet and outlet are reversed. Now that I know how they work I'd bet you could take one of those small 12 volt diaphragm air compressors that are sold for filling tires on cars and reverse the inlets to make one. The collection jar was broke years ago and replaced with a mason jar. Bleeding brakes has been a piece of cake since I bought that $5.00 used pump.

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