Well, I believe the saga has come to an end for now. I need to remind
myself that I should not concern myself with those potential areas with
a small degree of chance.
I purchased a new master cylinder and installed it. Initially, I solved
the inability to drain the rear brake reservoir, but had an issue with
the front brakes. After a few hours of contemplating - read doing
nothing - I tried again and after cracking a few valves everything was
fine.
Even fixed a leaky brake line.
Tomorrow I will complete the bleeding of the system which is 90% done,
but needs the final test and then be on my way.
My issue was indeed a faulty MC. Upon removal of the old MC, I was
somewhat shocked at the incredibly degraded and nasty rubber seal where
the MC mates to the firewall. I'm lighter in the wallet, but a whole
lot safer.
Many thanks to all who helped with this issue and I saw a real life
example of why it is important to keep the brake fluid clean and changed
on a regular basis.
Now on to the next project....
R. Ashford Little II
www.geocities.com/ralittle2
-----Original Message-----
From: Dave Massey [mailto:105671.471@compuserve.com]
Sent: Monday, February 18, 2002 4:15 PM
To: R. Ashford Little II
Cc: 'Dave Massey'; '[unknown]'; 'Triumphs@autox. Net'; 'Randall Young'
Subject: RE: Please HELP with brake bleeding problem
Message text written by "R. Ashford Little II"
>I've heard. I've spoken with Dave @ TRF and Apple Hydraulics and they
>told me the following.
>
>1. Apple: the brake master draws 90% of it's fluid from the rear
>portion of the reservoir (front brake area) so it's not unusual that
I'm
>not depleting the front reservoir area even by bleeding the rear
brakes.
>
>TRF: didn't mention this and he thought that I since the front and back
>brakes are totally separate then this should not be the case.
The rear reservoir is larger because it services the front brakes and
disk
brakes are self adjusting through the mechanism of advancing the pistons
as
the pads wear. This requires a significant amount of fluid and a larger
reservoir is required to accomodate this. The baffle between the two
reservoirs does not extend all the way to the top of the plastic
reservoir
and fluid level will equalize intil this level is achieved. Beyond that
they are separate.
>2. Both companies mentioned the PDWA as a likely culprit. Not that it
>was bad, but that the mere bleeding of brakes can cause the piston in
>the PDWA to go off center. If so then this is a possible reason for
not
>drawing fluid from the front portion of the reservoir.
There is no hydraulid interconnection in the PDWA. Furthermore the PDWA
does not "shut off" flow to one side or the other. It merely signals an
imbalance in pressures front to rear which would result from a slow
leak.
Even if it did shut off flow to one side that would not prevent fluid
from
bleeding from the connection at the master cylinder. This is not the
issue.
>Question: I noticed that the wire that is supposed to be running from
>the PDWA switch to my dashboard is not hooked up. I see no wire that
is
>left unconnected. Is this wire part of the wiring harness or is it a
>single wire that I could order and hook up?
Forensically speaking, this suggests that there has been a problem with
the
brakes for a while and someone disconnected this wire to extinguish the
light. This is, of course, merely speculation.
However, if the fluid level is below the baffle and opining the front
connection causes a drop in the rear reservoir, then I suspect that the
port that leads from the front reservoir to the front portion of the
bore
is blocked and fluid is passing past the fluid cup on the front piston.
The blockage may be a foriegn object (dirt?) or it may be that the
return
spring is broken and the small fluid cup that closes off this port is
not
pulling off the port.
In either event, I recommend dismantling the master cylinder and
finding/rectifying the problem.
Dave Massey
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