Re: Brake bleeder

[ejfluhr@austin.ibm.com (Fluhr)]

Esteemed q-list Igor Kessel cautions:
>No, Dan, 5 to 10 psi max! You may blow out the O-rings and seals in your
>brake system if you apply too much pressure.
>Even at 10 psi you will pop that plastic reservoir cap off the reservoir
>and have a geyser of brake fluid all over your car. BTDT.
>...
>I machined an Al ring and knurled it on the outside. After which I press
>fitted it over the OEM plastic cap with some Armstrong A-12 epoxy just
>to make sure that the ring holds the cap tight. Works well so far. The
>Al ring prevents the plastic cap of expanding under pressure and popping
>off the threads on the reservoir's neck.
>If you don't have the machining facilities at work I suggest that you do
>buy that $30 metal cap just to be safe.


Here is another data point, at the other end of the spectrum, just FYI.
Take it with grain of salt, and keep Igor's precautions firmly in mind
when you decide what to do.

I have successfully used, on several '80's era Coupe braking systems, the
setup that Dan was asking about.  This involves a spare plastic resevoir
cap with the Camel metal bolt-in schrader (sp?) valve.  I set my
compressor pressure regulator to 20psi, and clamp the air hose right
to the schrader valve on the resevoir cap.

I have not had any brake system leaks (o-ring failures, etc.) with this
pressure, nor has the resevoir cap ever blown off the resevoir.  It has
always worked fantastically well.


>You also need a transparent intermediate container made out of glass (or
>poly carbonate if you don't use ATE Super Blue brake fluid coz this
>aggressive blue $hit eats through poly carbonate in a few minutes after
>which the container goes KABOOM! under pressure and splatters brake
>fluid all over the engine bay. BTDT).

I don't use an extra fluid resevoir.  I do have to top off the car's
brake resevoir after bleeding 1 or 2 calipers, however.  It is a little
more work than having a secondary resevoir, but is still a very easy
and quick 1-man job.

Does anyone know what kind of fluid pressures the brake MC generates
when you stand on the brakes (like in a 60-0mph test)?  I believe it
would be easily in excess of 20psi, no?

Later,
Eric
'85 Coupe GT
---
Eric J. Fluhr                                Email:  ejfluhr@austin.ibm.com
630FP Logic/Circuit Design                   Phone:  (512) 838-7589
IBM Server Group                             Austin, TX