Re: alfa-digest V8 #72 - Clutch Bleeding 101

[AlfaNeely@domain.elided]

       In Alfa Digest V8 #72, Robert Favali asked about clutch bleeding.  The 
comments of Charles Slayman in the same Digest are appropriate.  I agree that 
if the clutch has half an inch (= 12mm) of travel, that should be adequate or 
close to enough to disengage the spider clutch.
       I have had the facing of a clutch disk blow off and jamb between the 
flywheel and pressure plate.  That was not on an Alfa, but an American V8 
that I over wound.
       I have also had the clutch disk rust to the flywheel.  That is only 
after the car has sat for a long period.  To break it loose, put the car in 
third or fourth gear, push down the clutch pedal and try to start it.  If 
that does not work, start the car in low gear, shift to third or fourth, push 
down the clutch and wrap the engine.  The engine should have enough power to 
break the disk loose.

       Do not worry too much if the clutch is obviously working, but not 
quite disengaging completely.  If the clutch is close to disengagement, but 
not quite, there may still be bubbles in the system.  Get the car running and 
drive it around a bit.  The bubbles should jar loose and move to the high 
points in the system.  If the high point is the clutch master, the problems 
are over.  If it is the clutch slave, one additional bleeding may help.
       If you cannot get the clutch to disengage enough to drive it, try 
wrapping on the fittings with a wrench.  By wrapping, I mean pecking lightly 
on the side, do not beat things up or smash a huge wrench into it.  Air 
bubbles can be trapped any junction in the hose, such as where the flex hose 
attaches to the steel tube on the rear of the cross member.  As someone 
pushes the pedal up and down, wrap on the side of the fittings to jar the 
bubbles loose.  In some cases, it will help to release the bubbles if you 
crack open the fitting slightly and wrap it with the wrench.

       To bleed a dry clutch system, I do it from underneath.  I open the 
bleeder, push the clutch rod into the slave and close the bleeder.  The 
spring in the slave should push the piston open and pull fluid from the 
clutch master.  Repeat several times and the job should be done.
       I have not had great success bleeding the clutch by having someone 
pump the pedal.  If the system is dry as when the clutch slave is new, the 
pedal does not move enough fluid to fill the system.
       I have never used a mighty vac nor speed bleeders.  The old fashioned 
way seems to work fine.

       By the way, for bleeding brakes, I generally allow gravity to do most 
of the work.  Open each bleeder in turn and allow fluid to run into a 
collection pan through a length of clear vinyl tubing.  Finish with a pump or 
two to make sure no air crept back into the bleeder.
       The earlier comments about air bubbles moving when the car is driven 
apply here.  This is especially true with a dry system.
       If you are replacing just the master cylinder, the brake tubing should 
be pretty well full of fluid.  Fill the master, pump the brakes a few times 
to move fluid into the cylinder bore, but do not open the bleeders yet.  Then 
open each fitting where the tube attaches to the master.  By opening the 
fitting slightly and tapping or wrapping with a wrench, air will move out of 
the fitting.
       Then you can bleed the brakes, but you might not need to.

Ciao,
Russ Neely
Oklahoma City

--
to be removed from alfa, see /bin/digest-subs.cgi
or email "unsubscribe alfa" to majordomo@domain.elided