Topic: Vacuum brake bleeder.


Gary M.    -- 09-04-2012 @ 4:02 PM
  What is the general opinion on vacuum brake bleeders for use on our old Fords? Do the vacuum bleeders effectivly pull all the air out of the lines or do I have to jack the car to create high points for air release ? Thanks Guys...


supereal    -- 09-04-2012 @ 8:05 PM
  I've never had much luck with vacuum bleeders. It take a lot of fluid, yet still leaves air in the system. Pressure bleeders connected to the master cylinder never seem to fail. If you don't have access to one, there are less expensive models on the market.


oldford2    -- 09-05-2012 @ 4:35 AM
  My pressure bleeder is my wife. Pump and hold then open the bleeder. Hose on the bleeder feeds into a bottle. 4 cycles and re-fill the m/c and go to the next wheel. We do this every fall and never any problems. May be old fashioned but it works. John


Gary M.    -- 09-05-2012 @ 6:56 AM
  This is a brand new dry brake system with all new components, hoses, and rubber parts.


TomO    -- 09-05-2012 @ 7:51 AM
  Gary,

The vacuum type bleeders leak vacuum around the hose and the bleeder screw. This is not much of a problem on cars with the master cylinder mounted under the hood, but does make bleeding more difficult when the master cylinder is mounted under the floor.

You should have bench bled the master cylinder before installing it. It should have come with a plug and instructions. This is especially important if you are using silicone brake fluid. You may damage the master cylinder by not doing this.

If you did not do this, I would remove the master cylinder and do it. It can be done on the car, but it is difficult to see that all of the air has been bled out when the master cylinder is installed.

After bench bleeding the master, install it and tighten all connections. Then have an assistant press on the brake pedal, without pumping the brakes (pumping at this stage can bring air back into the master), and open the right rear bleeder screw. Close the bleeder and have the assistant release the pedal and push down again. Repeat the procedure until the fluid has no bubbles. Keep the master cylinder full, by refilling every 3rd time. Repeat this procedure at all wheels, ending up at the left front.





Tom


Gary M.    -- 09-05-2012 @ 6:10 PM
  When I said dry I didnt mean the master, thats has been bled. However, when using a pressure bleeder, is bench bleeding necessary or does the fluid push right through all the ports ? Same question goes for vacuum bleeders, wouldnt the fluid get sucked through the ports in the master thus pulling out the air through the brake lines toward the wheel cylinders? Just curious,I havent decided which method to use yet. Thanks...


supereal    -- 09-06-2012 @ 9:33 AM
  The residual pressure valve in the master retains fluid, and the vacuum bleeder is supposed to suck the air and fluid past it. We use a "Mi-T-Vac" to test such things as heater controls but, try as I must, I have yet to achieve a successful full brake bleed. Old Ford brakes can be tough to bleed, in any case, as the master is lower than the wheel cylinders, and I got really tired of squeezing the MTV handle. As Tom said, there is some vacuuum leakage around the bleed screws. The "pump and hold" method does work if your helper can follow the steps. My wife refuses, after all these years, to assist me. Also, be sure the master cylinder is kept absolutely full as you use that method.


Gary M.    -- 09-06-2012 @ 6:04 PM
  They make a self bleeder valve with a check valve which is spposed to allow for 1 man bleeding. I noticed these valves have some sort of sealant on the threads so that there is no air leakage around the threads. I wonder what this sealant is and if it would aid in vacuum bleeding from the wheel cylinders...


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