Re: [MV] Brake Bleeding Tricks Anyone???

Lee Ethridge (leeethridge@ibm.net)
Mon, 26 Jan 1998 07:39:29 -0600

I've read many responses here, but not one that I've read has fully
described the typical recommended procedure, so I thought I'd go through
it.

Attach a clear plastic tube to the bleeder screw. (Clear plastic makes
it easier to see the bubbles as they travel down the tube. Make sure
the tube fits the nipple tightly.) Place the end of the tube in the
bottom of a container. (During the bleeding process, this end of the
tube will become submerged in brake fluid, which will help prevent any
possibility of drawing air back up into the system.) With the bleeder
screw closed, pump the pedal several times rapidly, until the pedal is
high and firm. On the last stroke of the rapid pumping, hold the pedal
down firmly. Open the bleeder screw slightly and leave it open until
just before the pedal hits the floorboard, then close it quickly.
Repeat the process until tired 8-), or completely satisfied that the
brake fluid coming through is clean and free of bubbles. Don't forget
to keep refilling the master cylinder.

(Obviously, this method requires a friend, and some coordinated shouting
back and forth. Have your friend in the car yell "close" just before
the pedal hits the floor. And, be sure you don't open the bleeder screw
so much that the brake pedal goes to the floor too quickly. If it does,
you won't be able to close the bleeder screw before the pedal hits the
floor.)

I've tried some of the other methods, particularly the one-person
bleeder kits and vacuum bleeding. Nothing that I've tried works as well
as the two-person method I've described above.

Having read some of the other tricks, I suggest trying the rapid-pumping
trick mentioned elsewhere, followed by the method I've described above.
The rapid-pumping trick should move the big air bubbles, and the
recommended procedure should take care of any remaining small bubbles.
Notice that in the typical recommended procedure the brake system is
highly pressurized the entire time the bleeder screw is open. This
compresses large bubbles into smaller, denser ones that will move down a
tube more easily, and helps ensure no air is drawn in through the
bleeder screw threads.

Lee

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