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Clutch Bleeding

To: "V8 list" <mgb-v8@autox.team.net>, <MG-MGB@yahoogroups.com>,
Subject: Clutch Bleeding
From: "Paul Hunt" <paul.hunt1@blueyonder.co.uk>
Date: Mon, 11 Jun 2007 10:16:20 +0100
After having read so often how difficult bleeding the clutch can be when I 
had replaced the master, slave and flex hose some years ago I didn't even 
bother, but instead reverse filled the
system by connecting a Gunsons EeziBleed on very low pressure to the *slave*
nipple, which needed no bleeding at all.  Since then I'd heard about
clamping the slave piston into the bottom of the cylinder, and even
connecting the right-hand caliper to the clutch slave and using the *brake*
pedal to bleed or fill the system (which I first came across via Dave Dubois 
from a posting to an MGA bulletin board by Ian Pearl), but until this week 
hadn't had an opportunity to try either.

An acquaintance has just bought a 1978 GT as a non-runner for 620 quid which 
has stood for 4 years, with a silent fuel pump and a clutch pedal that went 
to the floor with no resistance.  The clutch master was full, with pretty 
murky fluid so I don't think the PO had simply topped up a leaking system. 
Opening the slave nipple and pumping got no fluid through, just lots of 
gurgling.  I pressed the slave piston right back into the cylinder as per 
tip 1 but that made no difference.  I hadn't got my Gunsons with me but I 
wanted to try tip 2 as well, so I then siphoned all the fluid out of the 
clutch master, connected the right-hand caliper to the clutch, and got the 
owner to pump the brake pedal gently.  Within a few pumps fluid rose up the 
clutch master whilst barely reducing the brake master level (the large 
transparent reservoir) hardly at all.  The result was full clutch piston 
travel and the correct biting point with no further ado.  It was also easier 
than using a Gunsons, which needs a bit of fiddling about to connect to the 
slave nipple as well as a source of air pressure at just a few psi.  The two 
nipples are the same size so a length of plastic tubing fits both, even the 
spanner size is the same.  Time will tell whether there is a leak or some 
other problem in the hydraulics yet to be discovered, but I would definitely 
use this method again to either fill or bleed the clutch over the Gunsons 
reverse fill/bleed method and certainly the normal fill and bleed process.

FWIW the fuel pump was easy enough to get going by tickling the points, but 
was only pumping drops.  I parted the solenoid and pump body to check the 
one-way valves and filter but they were fine, also removed the points to 
reface them.  Along the way I found the air chamber cover bolt was barely 
finger-tight.  Reassembled, reset the throw of the points, refitted, and 
bingo - plenty of flow and no leaks.  The column switches were flopping all 
over the place - they had slid up the column and off the locating notch so 
that was easy enough to fix.  The hazard wasn't flashing one side, so opened 
it up and cleaned the contact surfaces, but I could never get a reliable 
contact to the one terminal so one side kept going off and on as I wiggled 
the moving part of the switch about, so we cut our losses and bought a new 
switch.  So the next step is to put it in for an MOT (annual test) and see 
what else fails.

PaulH.

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