Posted by Joe Lorenzino on Saturday, April 10, 2004 at 2:52AM :
In Reply to: Re: Power Brake Booster and Mico Lock on my 61 WM300 - Questions posted by Jerry Henry on Saturday, April 10, 2004 at 0:46AM :
At my first job, one of the old mechanics had a home-build bleeder unit that worked real slick. He used to be the only mechanic at a trucking company, and this thing let him bleed brakes all by himself. The main unit was a used pressure tank (I think an old freon canister)that now had a screw on lid, a pressure gauge, a metal tire valve stem, and a 10ft length of hose that ended with a valve that had a hydraulic swivel fitting for an outlet. He had made up various adapters to go from the swivel to the top of common master cylinders. The adapters were usually an old MC lid, with a connection to the swivel, and a rubber gasket for sealing. The PW adapter would just be a pipe nipple to fit the threads on the MC fill plug. He also had a few adapters for "back bleeding" (from the wheel cyls back towards the MC)that were made from what looked like a grease gun tip that fit over the bleeder screws.
To use it, the tank was checked/filled 1/2 way with fluid, valves closed, then pressured up with shop air. (don't remember how much he used, but that back-bleeding needed slightly more) The right adapter was attached to the MC, swivel attached to that, then the hose valve opened. He would then go around with a catch can and a clear hose that fit the bleed screws. Install the hose, open the screw till no more air bubbles, close screw, go to the next. He always started at the left front, but I think it was because he was paid flat rate, and was at that corner to attach the system anyway.
If he had a particularly "difficult" one, and systems with remote boosters can be that way, he would resort to Back Bleeding. The adapter was put onto the MC with a drain hose from the swivel into a catch can. ( usually a glass jar so he could see bubbles) He would then push fluid back towards the MC starting from the furthest corner, to the nearest. Some of the boosters were a real bear, and had multiple bleeders that had to be bled in a certain order depending on the model.
I am thinking most of us probably have most, if not all of the parts to build one of these things already "in inventory", so the cost would be pretty low. It does make brake bleeding a very simple one man job. J.V.L.
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