I have bled many brake systems...small cars...big cars...small and big planes....but i am at my wits end with this single cylinder system in my buick special. I have put plenty of fluid through it....started at the left front and worked back to the right rear.... but keep getting a spongy pedal that pumps up. I replaced the master cylinder with the expectation that it was defective...but I have the same symptom. I just cannot get the air out of this thing...I always thought of myself as a good mechanic but i am now humbled at trying to figure this out . Does anyone know of a "trick," or some spot in the system where an air bubble might hide??? Like the top of the wheel cylinders for instance? I know there has got to be a way to get all the air out....! Any and all suggestions would be greatly appreciated. Thanks ahead of time!!! brad
Not trying to insult you or anything... but how far up are are the drums adjusted? that make a low pedal. o No:
Lacking a power bleeder, I've had to idle the engine on my 'Lark to get a good bleed. Not the best thing, but it worked.
Absolutely no offense taken'...I'm the one beggin' for help. The pedal pumps up to its normal position....that is why I thought there's air trapped somewhere. (The star wheel adjusters move freely and are being grabbed by the cam) The system is a manual single master cylinder unit. I will probably end up closing off the fluid at the proportioning valve to figure out which line i can't get the air out of....maybe a power bleeder would be a good investment...any suggestions on a reasonably priced/good quality bleeder?
That's cool ... doesn't matter who it is... I start with stupid stuff.... I fnd the it's allwasy something simple that butt heads with the worst... As far as a bleed set up.... I've never tried it on a car, but.... On fork lifts at work, I have threaded a male air coupler into the the lid on the reservoir and plugged it into a 1/4 npt regulator set at 10-15 psi. Works great on those. just keep an eye on your level or you will just have to start over. Maybe if you can find a spare lid for reservoir, this will work for you. Like i say i have never tried it on a car, but the principal is the same.
Bleeder Jar. Yea, first make sure your DRUM brake adjustment is correct. Then this is a great way to bleed your brakes. Take a clean clear glass jar {MAYO, ECT.} with lid and a clear hose and run into the jar. Fill the jar with enough clean Brake fluid to cover the end of the hose when placed in the bottom of the jar {1" 0R 2"}. To help hold the hose in the botton of the jar, into the fluid you can drill 2 holes in the jars screw on lid . Slip the hose through one of the 2 holes. Drill the hole so that it is a snug fit to hold the hose from pulling out of the fluid in the bottom. The other hole is a vent when the lid is screwed on. The clear hose can be fish tank air hose. Slip the other end of the hose over the bleeder end. It must fit snug. Start at the futhest wheel first. With the Master Cyl. full, open the bleader with The jar and hose connected. Have an assistant slowly pump the brake peddle. Sometimes rapid pumping can aerate the master cyl. fluid. Watch the fluid pass through the clear hose till you see no air bubbles. Then close the bleeder before removing the hose. Move to the next rear wheel, then to the front right, then the drivers front. Usually I repeat the process 2 or 3 times to get out all the air. Remember to keep the master cyl. filled and that the jar hose end stays in the fluid so not to suck air back in when the brake peddle is released. This has always worker for me and my Mechanics. And I have serviced many Automobiles and medium duty trucks in my 30 yrs exp. I have a pressure bleeder and a vac bleeder that I dont even bother to use because its so easy. And no mess to clean up. NOTE: After loosening the bleader, check each fore play in the threaded bore, loose threaded bores can let air back into the system through the threads when OPEN. Also check master cyl. push rod for correct freeplay.
after spending a week on mine with the same problem and all new lines and equipment i had to have it power blead. best 75 bucks i've ever spent however.
Wow! Thanks guys....I'm going to go back and recheck all the star-wheels again (to make sure the drums are really adjusting) and then bleed the brakes just the way you suggested! Cheers! :beer
Brad The best way to adj those drums is to tighten them up till they can't be rotated, then back off the adjustment till you hear a light even drag on ea wheel. as mentioned above you should start with the furthest bleeder away from the the m/c, two people, pump-hold, break b screw & tighten quickly then re-pump and repeat till there's NO air. I assume you bench bled the m/c before installing it. :TU: good luck. Gene
True on convenional bleeding which he has tryed, But using the jar and submurged hose tec. He can leave the bleeder opened and pump the peddle slowley without opening and closeing the bleeder. The hose submurged in the brake fluid in the jar will not let air back into the system.
