Don:
It sounds like the new M/C is bad. The M/C has two separate
circuits, and it sounds to me like the rear braking circuit is not
operational. Since the pedal only goes down halfway, and you are getting
fluid out of the front, the secondary piston may well be seized. The
primary piston and front braking circuit seem to be fine. To get full
pedal travel, both primary and secondary pistons must be free to move.
Half movement is bad mojo.
Don't worry about uncentering the PDWA piston. When you are done
getting everything bled, you can easily recenter it with a small screw
driver. I would try a little more pressure on the pedal to see if you
can free the secondary piston, and if no luck, would return the M/C to
TRF for a diagnosis.
Vance
-----Original Message-----
From: owner-6pack@autox.team.net [mailto:owner-6pack@autox.team.net] On
Behalf Of don becker
Sent: February 12, 2006 8:48 PM
To: 6pack@autox.team.net
Subject: Brake Bleeding Question
I've checked the archives but wasn't able to find this particular
problem.
It seems that I'm unable to bleed my brakes (classic method - Bentley)
since
the pedal meets resistance about halfway down. (halfway meaning about
halfway from normal resistance to hitting the floor)
I suspect I may have done something wrong during the following sequence:
1. Rebuilt PDWA - new o-rings, centered the piston, etc.
2. Installed rebuilt Servo from Partco (Ohio)
3. Installed new clutch cylinder
4. Installed new brake M/C (from TRF)
5. Filled resevoirs with Castrol LMA
6. Bled the clutch cylinder (gravity method)..no problems
7. Put car up on jack stands..removed all wheels.
8. Started with passenger side rear per manual, however pedal was not
pumping any fluid. It seemed to go to the floor pretty easily according
to
my assistant.
9. I then decided to try the front brake (passenger side) and was able
to
get fluid pumping into the glass jar.
10. Went back to the rear brake again (passenger side) and this time the
pedal only wants to go down halfway? (don't want to upset the PDWA so I
didn't push too hard) Still no fluid. I even tried my Mityvac and
couldn't
coax any fluid out.
11. I then noticed the parking brake was on...dumb me...not sure if this
caused anything or not.
12. Tried the rear (passenger side) again and same result...pedal goes
down
halfway.
13. Tried the rear (drivers side) and same result...pedal goes down
halfway.
Anyway, it started to get dark so I drove the car back into the shed.
So, now I'm asking myself (and the list) -
Should I have bench bled the M/C prior to install? I read in the
archives
that the gravtiy method works for the brakes as well as the clutch.
Could the PDWA (if not centered) cause this symptom? Per Bentley, if the
brake light and oil light glow dimly then it's OK. I checked several
times
and the oil light and brake light both glow. Also, there is no leaking
fluid
from the PDWA...like there was before I installed new orings.
I've bled a lot of brake systems in the past and never experienced this
type
of problem.
Has anyone else experienced this?
Thank you in advance for any replies.
Don Becker, 74 Mallard Blue CF19716U
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