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Hydraulic Clutch Initial Setup

To: land-speed@autox.team.net
Subject: Hydraulic Clutch Initial Setup
From: ardunbill@webtv.net
Date: Fri, 10 Nov 2000 10:39:09 -0500 (EST)
Pondering "successful" hydraulic throwout bearing installation, it
occurs to me that in order for self-adjustment to happen, the unit would
have to be set up so that the slave piston was a bit forward of its
rearmost position, say 1/8" or so, when all slack was out of the
assembly. So  when the clutch fingers moved back a little due to disc
wear, the piston could follow suit, and merely suck a little more fluid
from the master cylinder. 

The effective travel of the slave piston is given as .550", so I assume
that the remainder, .425", would have to be sufficient to give a full
release of the clutch disc, assuming that the master cylinder and clutch
pedal delivered enough fluid. Hence Rich Fox's advice to just start with
the largest master cylinder.  Obviously one has to "wait and see" how
all the variables shake out, how much pedal pressure results, and how
much pedal stroke is necessary.  I suppose if the piston moved too far
it could come clear out of its cylinder, or past its seal, etc., or mess
up the clutch fingers.  A clutch that releases fully and cleanly is
nice; one that drags, stinks.  Literally and figuratively.  I smelled
mine at Maxton on Sept. 30.

I don't see anything in the design here that retracts the piston, so I
assume this setup lets the actual throwout bearing sit against the
clutch fingers and spin, if it "wants" to.  That was a no-no in the good
old days, since it wore the throwout bearing races and eventually
produced a noise, but in this application, probably matters not.  

ArdunBill

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