From: Randall Young
ryoung_at_NAVCOMTECH.COM
The pedal won't hold pressure.
Do you mean the clutch releases at first, and then if
you hold the pedal down it eventually re-engages ? Unless you can see a leak
somewhere, that means the return valve inside the master cylinder is leaking. A
MC rebuild should fix it.
Do you have to adjust the fork & plunger on the
master & slave?
The MC fork should need adjustment only once (if
you've disturbed the pedal mounting or whatever), the slave fork needs to be
adjusted periodically as the clutch wears. In both cases, you need a little
freeplay, but only a little.
Also I have the plunger in the bottom hole of the arm
coming off the clutch to the slave.
IMO the main thing is to have the push rod in-line
with the slave cylinder axis. ISTR the middle hole is the 'correct' one on a
TR3.
The other problem is when I
first depress the clutch, it goes down fine, then there's nothing... it feels
as if it wasn't even connected...The resevoier is full and I see no leaks
When you bleed the slave,
do you get fluid under pressure ? If
not, the MC may be airlocked, try loosening the outlet fitting and pushing the
pushrod in by hand. If you still don't
get anything, you're probably looking at a MC rebuild. There's a spring inside
that sometimes breaks.
When I shift on my '3B full synchro gearbox, I have
to apply too large a pressure on the stick. No screeching of the teeth however.
If I double clutch, shifting is a lot easier. What is the problem?
That's often the symptom of poor clutch hydraulics,
you aren't disengaging as well as you should. Does the problem get better if
you for sure put the clutch RIGHT to the ground? Is it worst in first? Those
are symptoms of that problem.
The clutch in my TR3 has mostly gone away. The top 2/3 of the pedal travel doesn't do
anything. The fluid level was a little down, but not far. No I couldn't detect any leaks. Jacked it up
and had my kson push the pedal. It looks
to me like the master is working but that the travel of the slave is way
to short.
Randall Young ryoung_at_NAVCOMTECH.COM replies
Alan, if the slave needed rebuilt, it would be
obvious from the fluid dripping from it. The most likely explanation for your
problem is a broken taper pin. However since it's a bear to change (have to
remove the transmission, which means taking the trans tunnel out ...), best to
exhaust all other possibilities first.
Check that the spring on the slave is present, and is
returning the slave piston all the way home.
Then check the free play in the push rod, it should only be something
like 1/32" (but there does have to be some).
A broken taper pin will frequently show up as a huge
amount of free play, like 1/4". Check that the clutch pedal is returning
to the top on it's own, that there is some free play in the pushrod to the MC
without having to pull the pedal up.
Before pulling the tranny, you can try rebuilding the
MC. The internal spring sometimes breaks (mine was in 4 pieces !) which also
causes lack of travel problems.
No one seems to list that spring for the TR3A (it's
not part of the repair kit), but the one from a TR4 will work just fine. Moss P/N 582-065.
If you do have a broken taper pin, I suggest
installing a new pin, then cross-drilling through the fork and shaft for a
1/4" grade 8 bolt and Nylock nut. I forget the bolt length offhand, but
it's best to choose one that's a little long, so the shank enters the fork on
the side opposite the head, and then cut the threads off flush with the
nut. Check carefully to be sure the nut
cannot foul on the bolt heads in the tranny face.
Just measured the thickness of the graphite part of
the bearing and it has 4.7 mm of carbon above the steel holder. This is a late
100-6 bearing