[Fot] Spitfire Slave Cylinder Vexing Me

Sun Jan 19 15:29:56 MST 2014

To address lots of the responses, The physical placement of the clutch is
the same. The clutch line is all metal so no ballooning. However, the
silicone fluid left dark silty stuff in the system, yet the shifting was
off before it was thrown in. There are currently no leaks in the system,
other than when the fluid had blown past the lid of the master cylinder.

I never took the slave off and it worked fine for 4 years. Pedal feel isn't
much different than before the engine swap, but it is different. There are
no leaks anywhere, but it sure seems like a hydraulic issue. Thrust washers
are good, the engine wasn't even fully run in before it got parked. All
hardware seems to be in order. So the plan of attack is this:

New master, slave, pushrod, line. Install, bleed, and see. If it persists,
I'll pull the transmission. My 12th Spitfire and 43rd Triumph and this is a
first for me. Fingers crossed.

On Sun, Jan 19, 2014 at 3:10 PM, <Gt6steve at aol.com> wrote:

>  You didn't lose that stupid pin out of the clutch arm pivot did you?
> Silly assed corrugated spring rusts and falls out with the simple pin
> following immediately after.  I dropped a 3/8 or 5/16" bolt into the top of
> mine centuries ago and it was good forever after.
>
>  In a message dated 1/19/2014 1:07:26 P.M. Pacific Standard Time,
> duncan.charlton54 at gmail.com writes:
>
> Mike,
>
> A friend discovered silly putty-like gunk in his brake hydraulics after
> using
> a borrowed can of silicone fluid to refill reservoir on his brake system
> (previously filled with DOT 4 -- probably very old DOT 4, at that) as a
> get-it-home measure.
>
> I assume you reused the same clutch and pressure plate, so travel of the
> throwout bearing should remain the same.  Have you already checked to make
> sure that you haven't used all of the available travel in the slave
> cylinder?
> If so, lengthening the pushrod would seem to be the solution.  Is there a
> spring that withdraws the throwout arm?  If it pulls back too far, some of
> your pedal travel will be eaten up when taking up the slack, i.e.: when
> moving
> the throwout bearing against the pressure plate.  If there is a spring and
> you
> don't want to remove it (letting the bearing ride against the pressure
> plate)
> you could make a stop that holds the arm from retreating too far.
>
> I can think of several explanations for the symptoms you describe but it
> sounds like you've already looked at them -- 1) different "grabbiness" of
> the
> friction material, causing some drag on the pressure plate or flywheel, 2)
> bad
> pilot bearing dragging the gearbox input shaft,  3) air in the system, 4) a
> soft hydraulic hose that balloons out, eating up some of your pedal
> travel, or
> 5) the throwout arm not properly on its pivot point.
>
> If it persists, is there a way to alter the leverage on the clutch release
> lever or the clutch pedal to cause more travel at the throwout bearing?
> It's
> been a long time since I looked closely at the Spit setup.
>
> Duncan
>
> On Jan 19, 2014, at 10:57 AM, Mike Jankowski <mikeragtopeditor at gmail.com>
> wrote:
>
> > Ok, here we go.
> >
> > The flywheel, etc, were all taken off the 78 engine. There is no crank
> float
> on the replacement engine. In fact, it still had machine shop rebuild paint
> and a date that was the same as the last year the car it came from ran. The
> master and slave as well as line and disc were all replaced in April 2010.
> We
> can't find any leaks.
> >
> > When I pump the pedal, it makes no difference. However, sometimes
> downshifting is flawless, sometimes it grinds, sometimes it just is
> notchy. I
> always double clutch downshifting anyway, so that may help. However, in
> reading a few of the responses here, I think all that was on hand when the
> engine was first swapped and I discovered a nearly dry master was silicone
> fluid. I've flushed the system 3 times already, but am now wondering if the
> combo of fluids caused this. Also, the fluid was dark and had some
> residue. I
> blew out the line and master, but still same shifting issues.
> >
> > I left the transmission alone save for spinning the throwout bearing to
> check it, but I'm now thinking of pulling the transmission to check the
> pivots, etc.
> >
> > Mike
> >
> >
> > On Sun, Jan 19, 2014 at 9:58 AM, Duncan Charlton
> <duncan.charlton54 at gmail.com> wrote:
> > Mike,
> > No sign of leakage in the slave cylinder?  Do you have means to
> reverse-bleed?
> >
> > I have had a slave cylinder that was very hard to bleed the air out of
> completely.  You might try removing the slave from its mount, pointing the
> bleeder screw upward, and using a clamp to hold the piston in the bore, and
> then bleeding.  Even better, raise the slave cylinder above the master to
> make
> sure any trapped air bubbles have chance to rise.
> >
> > Duncan
> > (just down the road in Elgin, TX)
> >
> > On Jan 18, 2014, at 11:09 AM, Mike Jankowski <mikeragtopeditor at gmail.com
> >
> wrote:
> >
> > > Hi Everyone,
> > > I've hit the end of my rope on a problem with a Spitfire slave
> cylinder.
> > > Here's the facts:
> > >
> > > Car shifted perfectly until I swapped engines.
> > > Replaced 78 engine with a 76.
> > > Left trans in car, never touched it.
> > > Test drive after swap was good except shifting was notchy and reverse
> > > ground some.
> > > Opened clutch master, reservoir almost empty.
> > > Topped off with fluid, shifting still bad.
> > > Bled clutch, no real improvement.
> > > Double checked slave cylinder to make sure it didn't get loose, made
> sure
> > > it was all the way forward.
> > > Shifting was better but progressively worsened as driven.
> > > On the move shifting was ok, but hard to get into 1st, ore reverse, and
> at
> > > stoplight car would creep forward with clutch pedal to floor.
> > > Bled 2 more times, no real change. Had to doubleclutch up and
> downshifting.
> > > Pulled slave cylinder, put 1964 penny as spacer.
> > > Car shifted like new on test drive, and subsequent drive to grocery
> store.
> > > On return from store, as soon as started car could tell again not fully
> > > releasing.
> > > Notchiness, though not as bad, is there again.
> > > Slave cylinder is 4 years and 47,000 miles old. (I drive my Spit quite
> a
> > > bit as well as autocross it.)
> > > Also, at grocery store looked at clutch master and fluid had gone past
> the
> > > lid, but I suspect it was slightly overfull when we left home.
> > >
> > > Do I just replace all the slave cylinder bits? Not really sure what to
> do
> > > here.
> > > Thanks,
> > > Mike
> > > _______________________________________________
> > > fot at autox.team.net
> > >
> > > http://www.fot-racing.com
> > >
> > > Donate: http://www.team.net/donate.html
> > > Archive: http://www.team.net/archive
> > > Forums: http://www.team.net/forums
> > > Unsubscribe/Manage:
> http://autox.team.net/mailman/options/fot/duncan.charlton54@gmail.com
> _______________________________________________
> fot at autox.team.net
>
> http://www.fot-racing.com
>
> Donate: http://www.team.net/donate.html
> Archive: http://www.team.net/archive
> Forums: http://www.team.net/forums
> Unsubscribe/Manage:
> http://autox.team.net/mailman/options/fot/gt6steve@aol.com