Cary writes...
>Hi Tom,
> In reading the triumphs mail I noticed that you have several
> late model Spitfires. I asked this question earlier on the
> list, but didn't get any response, so maybe you can help me.
Hi Cary!
Normally the list is pretty good about answering this stuff but
sometimes they do the "I got it...you take it" fielder routine. :-)
Might be worth posting again to get more input.
Meanwhile I'll give you my own experience and thoughts on this
subject as long as you realize I'm *not* and expert in this area.
Take it with a grain of salt.
>I recently bought a '79 Spitfire and I now have a clutch
>problem. It quit disengaging. I removed the gearbox and
> checked out the clutch and it all seems fine. After
> re-installing the gearbox it still would not disengage.
> It appeared that the slave cylinder was not pushing the
> pin far enough. I tried adding a 1/4" spacer to the lever
> pin and got it to work. But, it would only disengage at the
> very bottom of the pedal travel (it felt like you had to
> put your foot through the firewall!). Well, this worked
> for about two weeks and then it quit disengaging again.
> Both the master cylinder and slave cylinder have been
> re-built and the hydraulics have been bleed repeadedly, so
> I think that's ok. Do you have any suggestions?? Thanks.
>cary
>'79 Spitfire
First off...You need to make sure the thrust washers in the engine
are still *there*! Pop the bonnet and push the crankshaft pulley
hard towards the rear of the car. Then have a helper step on the
clutch and look for forward movement of the pulley. Sometimes you
can just grab the pully and push it fore and aft and get the same
results.
Healthy thrust washers will allow no more than about .020" movement.
If you get something like 1/4", then the washers have dropped out
onto the bottom of the oil pan and serious engine damage is probable.
No need to read the rest of my message as this is your trouble. :-(
BTW....if this is *not* your problem, it's still a good idea to
measure this freeplay and compare it to the spec. It's possible
to install new ones without pulling the engine. I did mine last
year.
ON TO HYDRAULICS...
Okay....three months ago I jump into my car and the clutch pedal
goes to the floor. Pop the bonnet..opps....no fluid. Notice
heavy seepage on the firewall. I fill the MC so I can get to work
but it's clear I've drawn air into the system by letting it get
this low and my pedal now only functions near the end of it's
travel.
I order a clutch MC rebuild kit, but I decided to install that
in my spare MC from a '76 parts car. Figured I'd save time.
I honed and polished the bore as per net wisdom.
When I installed this "rebuilt" unit in my car I experienced
the strangest clutch behavior. A fairly rapid push of the
pedal gave me a nice normal solid clutch action. A slow push
allowed the pedal to go straight to the floor with *no* resistance
whatsoever. No loss of fluid though. Drove the car for a week
this way hoping it would improve...nope. Re-bled several times..
..no change.
Disassembly showed the cause. The MC bore still had small amounts
of cratering where rust had been deep down the bore. VERY difficult
to see even with flashlight.
Swapping the new seals, etc to the original MC cured the problem
completely.
Moral of story: You can't always rebuild these things so they
work reliably. An alternative to "new" is to send the MC and
SC out to White Post Restorations for re-sleeving.
ON TO CLUTCH MECHANICS...
I'm in the middle of a clutch/tranny swap on my '74 Spit. I'm
putting in a complete unit from my '76 parts car, and I'm replacing
everything that looks worn or sketchy. I have plenty of time to
do this so I'm trying to cover all the bases. Here's what I've
found so far:
The clutch fork pivot pin is worn as are the two brass bushings
pressed into the bellhousing. There's a good amount of "lost motion"
betwixt them. Over to the other side of the fork, the actuating
pin that comes outta the slave cly had worn by 1/8" in length
compared to a new one. *And* the hole end had _another_ 1/8"
of slop from wear to itself and it's stake pin. I'm replacing
all of these parts....think they came to less than $25 total.
On of the advantages of a hydraulic clutch system is that it's
self adjusting to compensate for wear. The slave cylinder piston
is "sprung out" at rest to remove any freeplay that develops.
New hydraulic fluid can then be drawn in behind it to take up
the gap. 'Course...there are limits though. You _do_ have a
spring in your slave, right? :-)
Other random thoughts...did you replace the pressure plate with
a new one? I hear this can go flakey and and give you the problem
you describe. Also....they say to "grease lightly" the splines
of the tranny input shaft with copper based never seize. Keeps
the clutch disk moving back and forth freely.
Good luck with this Cary...don't hesitate to write back to me or
the list if you have more questions.
Regards...Tom O'Malley
'74, '77 Spits.
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