Ron,
For some reason, Mityvac forgot to inform you in their instructions that air
can leak in around the threads of the bleed screw when it's loosened. If
you're stuck doing this as a one man operation, speed bleeders are a good
investment, or short of that, just smear a dollop of grease around the
threads of the bleeder valves while you work on each wheel.
I had this exact same problem that you experienced, but didn't yet realize
that the problem was the thread leakage. I gave up trying to use the
Mityvac after about ten minutes and called my 16-year-old to come out and
pump the brake pedal. Much easier, much faster. I've heard very positive
feedback on the speedbleeders.
Best wishes,
Jeff in San Diego
'67 RHD Spitfire Mk3 aka "Mrs. Jones"
'68 LHD Spitfire Mk3 frame-off resto project
The Totally Triumph Garage forums -- moderated, focused, friendly!
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----- Original Message -----
From: Ron Deaver <rrdeaver@emagichappens.com>
To: <spitfires@autox.team.net>
Sent: Sunday, November 05, 2000 11:11 PM
Subject: Problems w/bleeding brakes
>
> Hello all,
>
> By now I truly had hopes of sharing my story with a total brake
replacement
> on my 1980 Spitfire. The whole story will follow completion of the work,
> but I really could use some advice. It has been a long time since I did a
> total brake job (1974 Vega Kammback...), but this has turned into a major
> re-education and nightmare. The car has been on stands for a month now in
> total.
>
> Problem: Brake system stubborn when trying to bleed it. Little to no
> fluid coming down the lines from the Master Cylinder. Air bubbles never
> cease. Using a Mityvac unit. Lines were cleaned with brake cleaner (good
> old TCE), blown air dried, sat 1 week prior to reassembly. All metal
lines
> reused with exception of right rear. Pressure Warning Switch reused (did
> not disassemble, as there was no problem with it prior to brake work).
>
> Replaced to date:
> Front:
> Master Cylinder (professionally rebuilt, reuse of original reservoir),
> flexible brake lines (Aeroquip braided installed), professionally rebuilt
> calipers, new rotors, new pads).
>
> Rear:
> New drums, pads, all new hardware, new Aeroquip flexible lines, new wheel
> cylinders. Right rear metal line at wheel replaced due to stripped
fitting.
>
> Brake system had a problem with the master cylinder, where it would
> spontaneously lose pressure without predictability. You could be sitting
> at a stop holding the car with the brakes, then the pedal would suddenly
> drift to the floor.
>
> Now that the system is reassembled, I cannot seem to get any fluid to come
> out of the left front caliper after pumping the system with the Mityvac.
I
> did bench bleed the master with the DOT5 fluid, and then did it again with
> the Mityvac.
>
> Pumping the right front and the left rear did finally result in some fluid
> filling the Mityvac reservoir. I kept at it for a good 15 minutes of
> continuous suction with the Mityvac, and still I kept getting mainly air.
>
> I heard a rumor that you are supposed to use some sort of special grease
on
> the fittings when attaching the braided Aeroquip lines to the stock pipe
> fittings. Is this true? I doublechecked the fittings and they are as
> tight as they can go without stripping fittings or snapping lines.
>
> The line from the Mityvac is sealing tightly on the bleed nipples. It
does
> not appear that there is a airleak there. Could enough air leak in from
> the loosened bleed nipples to still cause air to bubble into the pump,
> making it appear like there is still air in the system?
>
> Would it be possible that the Pressure Warning Switch is a problem and may
> be jammed (wonderful reputation there, and harder to find a
> replacement)? How can I isolate the problem to the switch (I can't
replace
> every little part I touch, though it seems that way of late).
>
> I do hope that someone has the magic answer. Also, if someone knows where
> I can get a replacement electrical connection for the Pressure Warning
> Switch (normally part of the harness), I would be greatful. One of the
> connections seems to be pushed out of service and it does not seem to be
> repairable. Can't identify availability of this little rubber boot
> connection in the Vicky Brit catalog, nor the Roadster Factory catalog.
>
> Cheers,
>
> Ron Deaver
> Issaquah, WA
> 1980 Spitfire 1500 (yet to be named)
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