Re: Home made pressure bleeder? Help

[four.rings@mcione.com]

Martin,
here's a copy-n-paste description from my post to the list of a year
ago (it looks like any question reliably reappears at lest once a year). Please
don't hesitate to ask if you have any more questions.

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Here's a description of one poor engineer's pressure bleeder:

1. The cap.
Took the one from a 5000/100/200 P/S reservoir. It's the same cap as on the
brake reservoir. I paid $5 at a junk yard. I took the float out and enlarged the
hole to 0.476".
Bought two regular rubber tire stems (the narrow ones, there are 2 different
designes available). Ran one of the stems trough the 0.476" hole. I also
machined an Al ring and knurled it on the outside. I've put this ring over the
cap w/ the mil-spec Armstrong A-12 epoxy, so it prevents the plastic cap from
expanding under pressure and popping off the reservoir.

2. The reservoir.
Ordered a 1L chemical jar with a 110mm phenolic rosin screw lid from Edmund
Scientific. Drilled two 0.476" holes through the lid, spaced 2" apart. Ran the
second tire stem through one hole. Ran a chemical feed-through union through the
other. Inserted a 0.25" hard plastic tube into union so that when the lid is
screwed onto the jar the bottom tip of the tube touches the bottom of the jar in
order to pick up brake fluid from the very bottom of the jar. To the other end
of the union I connected a 1.5m Tygon hose with a quick disconnect for a tire 
stem on it's opposite end.
 
3. Pressure source.
Took an old freon tank. Brazed a brass *T* to its valve. On that T installed a
quick disconnect nipple for charging it from a regular shop air line, a pressure
regulator with a dial gauge and a 1.5m Tygon hose with a quick disconnect for a
tire stem.

Here's how I bleed the brakes:

1. Fill the car's brake fluid reservoir.
2. Screw the cap with tire stem on it.
3. Attach the quick disconnect from the jar lid to the tire stem.
4. Fill the jar with 1L of brake fluid. Screw the lid onto the jar.
5. Fill the modified freon tank with air to around 80psi.
6. Connect the quick disconnect from the freon tank to the tire stem on the
jar's lid.
7. Adjust the air pressure to no more than 10psi! You can blow the seals with a
higher pressure.
8. Bleed the clutch.
9. Bleed the wheels (RR, LR, RF, LF, RR).

Tips:

1. Test drive the bleeding sys with water first. A geyser of brake fluid WILL
ruin your paint!
2. Keep a bucket of water handy for that inevitable spill off. Should it ever
happen to you (the cap pops off, the jar breaks - whatever, FLOOD the sucker
with water!!! It is a lot more expensive to repaint the car than to rebleed the
spoiled brake fluid.
3. When bleeding the brakes keep the jar in a container. I use an empty 1 gallon
olive oil tin.
4. Thoroughly cover the fenders with rags. If you spill brake fluid you'll be
glad you did cover them, coz you'll have about 20 sec to salvage your paint
after which it's history.
5. Keep an eye on brake fluid level in the jar. If you miss and fill the MC and
ABS unit with air, it will require rebleeding of the whole sys over again. No
biggie, but it consumes time and brake fluid.
6. Bleed the old fluid into a clear bottle of the same capacity as the jar - it
will help you to determine how much fluid is left in the jar without having to
crawl from under the car.
7. Bleed the old fluid out through a clear Tygon hose (1/4" or 3/16 I.D.
depending on the size of the bleeder screws). It will make bubbles visible.
8. Use only quality brake fluid. I prefere German Pentosin DOT-4. Some people on
the list swear by ATE Racing Blue. Just don't use any Pep Toys, Quaker Trait and
other no-name $h*t, they like to ruin seals in the brake system. The only
acceptable domestic fluid would be Castrol LMA DOT-4.

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Igor Kessel
'89 200TQ -- 18psi (TAP)
'98 A4TQ -- mostly stock
Philadelphia, PA
USA
http://www.geocities.com/MotorCity/Garage/8949/homepage.html
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