[Shop-talk] Weird clutch petal

Doug Braun doug at dougbraun.com
Sun Oct 13 10:07:05 MDT 2019 

I agree, this certainly sounds like a problem with the reservoir shutoff
valve not closing properly.
If it were a problem with the main seals, a lot of fluif would have leaked
out.

I had the same problem develop in my Spitfire brake master cylinder.  It
turned out that the
"tipping valve" (the shutoff valve for the forward half of the cylinder,
was not seating properly.
It was part of an aftermarket kit I had installed several years ago.  I
re-installed the original one
(which I had kept), and the problem went away.

The lesson: In many cases a new part in an aftermarket rebuild kit can be
inferior to a used original
part.

Doug


On Sat, Oct 12, 2019 at 6:30 PM Robert Nogueirao via Shop-talk <
shop-talk at autox.team.net> wrote:

> Pat thank,  but having inspected the master it appears to be such a poorly
> made copy of a Girling I see nothing but trouble in the future.the piston
> does not slide smoothly in the bore leading me to think it is hanging up.
> Same with the reservoir cut off .
> Again thanks.
>
> Bob Nogueira
>
> On Oct 11, 2019, at 11:15 PM, Pat Horne <patintexas at icloud.com> wrote:
>
> You should be able to find a set of seals to try. Lots cheaper than a
> replacement master.
>
> In the past I found this kind of leak by having someone watching the fluid
> surface in the reservoir while I pressed the pedal down. On my master there
> was a rise of the fluid where the jet of fluid came out of the reservoir to
> cylinder hole, causing a “lump” in the fluid surface, indicating a bad
> seal.
>
> Peace,
> Pat
>
> Pat Horne
> We support Habitat for Humanity
>
>
> On Oct 11, 2019, at 10:46 PM, Robert Nogueirao via Shop-talk <
> shop-talk at autox.team.net> wrote:
>
> Okay bleed the lines no solution, chance of air in the lines is remote,
> the slave is higher than the master, the run between them is only a foot or
> so and the line turns down for only a couple of inches between them.
> Additionally the bleederis at the highest point of the slave.
> The lines are new as is the slave and master.
> I did disassemble the master to check it out and it appears to be a
> Girling knockoff. The piston and reservoir shut off valve feel cheaply
> made. I’m thinking that the reservoir shutoff may be leaking a bit until
> pressure is built up thus forcing fluid into the reservoir rather than to
> the slave.  Only way to check is order a new Girling master from Pegasus,
> basically a $125 gamble.
> Right now Donald and Pat are in the problem solving playoffs.
> Will advise if the gamble pays off
> Thanks for the suggestions.
>
> Bob Nogueira
>
> B
>
> On Oct 9, 2019, at 7:18 PM, Donald H Locker via Shop-talk <
> shop-talk at autox.team.net> wrote:
>
> It would sound like air to me, too, but that it works "90% of the time"
> which would indicate to me that one of the seals is not sealing properly.
>
> It's been a while, but I had a similar experience, and discovered that if
> I hit the pedal quick and hard, the clutch action was good; if not fast or
> hard enough, the pedal was soft.
>
> My guess is that a seal is old and not always flaring out to the MC bore
> when the pedal is pressed.
>
> Donald.
> --
> *Plain Text* email -- it's an accessibility issue
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>
> On 2019-10-09 8:03 p.m., PJ McGarvey via Shop-talk wrote:
>
> Sounds indicative of air in the lines, since the first pump is weak/soft,
> but as you pump it a few more times you get more pressure. Check for loose
> connections and then bleed a whole bottle of fluid.
>
> PJ
>
> ------------------------------------------------------------------------
>
> *From:* Shop-talk <shop-talk-bounces at autox.team.net> on behalf of Tom
> Shirley Sr. via Shop-talk <shop-talk at autox.team.net>
>
> *Sent:* Wednesday, October 9, 2019 7:46 PM
>
> *Cc:* Shop-talk <shop-talk at autox.team.net>
>
> *Subject:* Re: [Shop-talk] Weird clutch petal
>
> Air in the lines?
>
> On Wed, Oct 9, 2019, 6:38 PM Robert Nogueirao via Shop-talk <
> shop-talk at autox.team.net <mailto:shop-talk at autox.team.net>> wrote:
>
>    I have a  hydraulic clutch, Girling 5/8” master and a internal slave
>
>    that fits over the input shaft. Both are new.  Problem is I have a
>
>    really good feeling petal, no leaks and good operation 90% of the
>
>    time but occasionally when you depress the clutch to change gears
>
>    the petal feels soft and will not fully release the clutch. Letting
>
>    the petal out and again depressing it and the feel and release are
>
>    again normal. Reservoir shows no lost of fluid.
>
>    Since the slave is mounted on the input shaft and operates directly
>
>    on the throw out bearing there is no linkage to cause the problem.
>
>    Any suggestions as to what could be causing this problem?
>
>    Bob Nogueira
>
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