[TR] Clutch slave cylinder

[Creig Houghtaling]

Adrian,

I am going to respond here based on my experience with my TR6.  I believe
the parts and mechanisms are pretty similar.  Others can speak up if there
are differences that I am not familiar with.

Before I refreshed the clutch on my TR6 the pedal pressure was fairly heavy
by any comparison.  I found out the reason for that was the slave was
connected to the top hole in the clutch swing arm.  The top hole is the hole
closest to the shaft that goes through the bell housing.  Torque and lever
arm distance comes into play here.  So I moved the connection to the middle
and then the end hole and found the pressure to be lighter on my clutch
pedal.  But at the middle and outer points my pedal was not pushing my
clutch far enough to disengage the transmission.  The reason for this was
parts were worn causing slop in joints and links.  So to have enough throw
to disengage my clutch the slave had to be connected to the upper connection
point on the arm.  Over the next several months I replaced parts one at a
time till I had replaced everything.  New clutch, new throw-out bearing &
carrier, new fork, new shaft, new bearings in the bell housing where the
shaft goes through, new pin between the slave & swing arm, rebuilt slave
cylinder, rebuilt master cylinder, and new pin on the clutch pedal to master
cylinder connection.  When everything was refreshed I was able to connect
the slave cylinder arm to the bottom hole on the shaft.  This resulted in a
very smooth and easy to operate (by TR6 standards) clutch pedal.  At this
point I would still judge the pedal operation to be a little heavier than
most modern cars.  (By modern cars I am talking TR7s & TR8s.)

So my suggestion would be to avoid (if possible) anything that makes your
pedal pressure heavier.  On the other hand, the advantage to the smaller
bore slave might be if you do not desire to refresh all your other parts
right away.  You might like having the extra stroke available from the
smaller bore.

Creig
Creig Houghtlaing 314-401-7817
St. Louis Triumph Owners Association
www.sltoa.org



-----Original Message-----
From: triumphs-bounces at autox.team.net
[mailto:triumphs-bounces at autox.team.net] On Behalf Of ADRIAN DIX-DYER
Sent: Saturday, March 08, 2014 5:21 AM
To: Randall
Cc: triumphs at autox.team.net
Subject: Re: [TR] Clutch slave cylinder

Thanks to all who replied on the clutch slave cylinder question. My thoughts
on the subject seem to have been confirmed.
Particular thanks to Frank who has actually used on of 7/8" bore unit albeit
on a Toyota conversion.
As my car (TR4A) was a runner and not a driver, (no brakes working), when I
bought and stripped it for restoration I have no idea if the clutch
operation is heavy or light in standard trim.
Compared to a modern stick shift car is the standard TR4A clutch operation
heavy, medium or light?.

Adrian 1966 TR4A CT64306 O
Wales UK


On 7 March 2014 23:17, Randall <tr3driver at ca.rr.com> wrote:

> > I have been offered a NOS 7/8" bore unit at a fraction of the price. 
> > It
> was
> > originally intended for a BMC truck and it is the same casting.
> >
> > My question is, what would the effect be if I fitted the 7/8" unit?
> >
> > A heavier pedal?
>
> Yes, about 25% heavier. (The ratio of the squares of the bore 
> diameters, since area is Pi * R^^2).  You'll also get more travel at 
> the slave, which might possibly cause an issue with over-extending the 
> pressure plate (but I don't think so).
>
> Randall
>
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