[Fot] Spitfire Slave Cylinder Vexing Me

Sun Jan 19 14:10:57 MST 2014

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
> >  _______________________________________________
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> >
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