Mike, here is a small portion of recent list info on the subject
of Midget clutch bleeding:
-Dave
Subject:
MG Midget clutch
Date:
Wed, 10 Apr 96 08:04:24 -0400
From:
ALAN_COSTICH@HP-USA-om11.om.hp.com
To:
mgs@autox.team.net
Item Subject: cc:Mail Text
Jon,
I know your misery. I'm still working on mine. What does
seem to help is:
With the bleed tackle still hooked up to the bleed screw,
crawl underneath, disconnect the push rod from the throw
out fork, have your assistant open the bleed screw while
you
push the piston of the slave all the way in with the push
rod. When the piston bottoms, close the bleed.
Repeat as required.
Also, make sure the master cylinder has been bled. Loosen
the pipe at the top of the cylinder, have your assistant
press the pedal. Fluid should flow from the join. (Make
sure the painted surfaces are protected.) Tighten the
join.
Keep us apprised.
Alan
Weekend before last, I replaced the clutch master and slave
cylinders in my
B. There had been a lot of discussion on the list just before this
about
how hard it is to bleed a clutch and I didn't remember it being that
bad,
but my last experience was 15 years ago.
Years ago, I owned a '79 Spitfire and when I replaced the master
cylinder,
I let the car sit for half a day and then pumped the pedal a couple
of times
and the clutch was bled, but the clutch line in a Spit is strictly
vertical.
After the new cylinders were in the B, I bled the clutch at the
slave cylinder
with my boyfriend working the pedal. This obviously wasn't doing
any good.
Then we bled at the connection to the master cylinder. This
actually caused
the actuating rod down at the clutch to move and the clutch could
then be
pumped up so that the car could be shifted, but at a certain point,
it became
obvious that no amount of bleeding at this location was going to get
all the
air out of the system. I was out of clutch bleeding time and I had
to drive
the car to work, so I drove it pumping furiously on the clutch pedal
every
time I needed to shift. After three days of this, the clutch no
longer
needed to be pumped up--it had bled itself. I'm not sure if I'm
recommending
this as a procedure to be followed because pumping up the clutch for
every
shift is tricky. I'm a trained professional and can do this while
eating a
carne asada burrito.
Someone (Motorhead?) suggested pushing the slave cylinder rod into
the slave
cylinder after the system had been bled as much as possible. Based
on the
geometry of the system, this should work, but I don't know how
difficult this
is because I've never done it. If I were going to do it, I'd use a
big pair
of water pump pliers to push the end of the rod into the slave
cylinder
housing with the cap off of the master cylinder.
Good luck!
Denise Thorpe
thorpe@kegs.saic.com
Subject:
Re: MG Midget clutch
Date:
Sun, 7 Apr 1996 20:06:19 -0400
From:
KGSTUART@aol.com
To:
jbreen@ncpi.com, mgs@autox.team.net
The Midget is a very tough car on which to bleed the clutch
hydraulics. It
has to do with the angle of the mounting of the slave ctylinder and
the
position of the bleeder screw. The problem is that there is quite
often a
pocket of air left in the cylinder, no matter what you do. It is
amazing how
small a pocket of air will keep the system from operating. Try the
following:
1. Unbolt the slave cylinder, but leave the hydraulic line attached.
Let it
hang under the car. Loosen the bleeder screw and let the fluid
dribble out.
The idea here is to let gravity help you "prime" the system. Once
the fluid
is flowing freely, bolt the unit back onto the car, and bleed as
usual.
2. Crawl under the car, unbolt the slave cylinder, but leave the
hydraulic
line hooked up. Let it hang below the car. Remove the actuating rod
and the
dust boot. Get a c-clamp and fit it so that the pison is locked in
the slave
cylinder. Bleed the system, while holding the slave cylinder such
that the
bleeder screw is the highest point of the cylinder.
3. If the above does not work, this will........Buy a pressure
bleeder. There
is one made by Gunson that works well. I have also heard good things
about
the Mityvac system. They run about fifty dollars, but it will blow
the air
out of that system in 10 seconds. Well worth it........
4. Also, ,,,,,,Check that there is no wear on the clevis pin or the
shaft
hole of the slave cylinder actuating rod. If there is any wear on
these two
parts, it will cut down on the length that the clutch fork will
travel.
Good Luck.
Jon D. Breen was asking about cluych bleeding problems on Midgets. I
have
just replaced the clutch in my '70 Midget over the winter. After 2
days of
lying on my back while my neighbor pumped the pedal , the clutch
finally
works. After trying normal bleeding methods i finally took the slave
cylinder
off the transmission and wrapped Teflon tape on the bleed screw and
put it
back in. Using a vacuum bleeder and most of a bottle of Castrol LMA
fluid we
finally got all the air sucked out of the line. Seems like the
bleeder screws
are a little sloppy when you try to open them enough to get a good
flow, and
will get some air back into the system and defeat your purpose. Give
it a
try: at least it worked on mine.
George Chase
GeorgeC70@aol.com
'70 MG Midget
ubject:
Re: MG Midget Clutch
Date:
Sat, 6 Apr 1996 09:34:55 -0500
From:
RJohn50603@aol.com
To:
GeorgeC70@aol.com, mgs@autox.team.net
George,
My son and I have had exactly the same experience on our 1976 and
1979
Midgets. The clutch servo on these cars is difficult to bleed. It is
probably
because of the large inside diameter of the hard plastic tube
between the
master and slave cylinders and the high spot in the tube which is
unavoidable
with the design layout. You simply cannot get the velocity of the
fluid to
get the bubbles pulled down and out of the slave before you have to
stop and
refill the master.
My 73 MGB isn't this bad. Of course the diameter of the tube between
the
master and the slave is metal with a smaller I.D. for the greater
part of the
distance.
A Toyota wagon my wife and I had would actually BLEED ITSELF by
gravity
simply by filling the master because it was down hill all the way.
All the
MG's I have seen have that high spot. Seems like the engineers
designing the
system never had to bleed one or they would have followed the Toyota
scheme.
R
Johnson - Dallas
Subject:
Midget Clutch
Date:
Mon, 8 Apr 1996 21:57:38 -0500
From:
Michael Chaffee <mchaffee@ux1.cso.uiuc.edu>
To:
MGs <mgs@autox.team.net>
For those of you faint of heart, I can vouch that at least on the
'74
Midget, clutch bleeding can be accomplished by two people with some
time
and a hose. I'm sure it's easier with one of the magic tools, but I
don't have one of those.
While we're on the subject of clutch drag, let me mention one other
source
of clutch problems that may not be intuitively obvious at first:
the
thrust washers. When I first bought my Midget five years ago (Five
years!
And it seems like only yesterday...), it had a severe clutch chatter
problem. Replaced the entire clutch, and now it not only chattered
but
dragged a bit as well. I lived with it that way for a few months,
then
finally decided to replace it. New clutch, replacement confirmed
good
flywheel - still chattered, still dragged just a little. Fast
forward to
this last Labor Day. I finally got around to replacing the engine,
and
discovered two things: 1. The old engine had roughly 1/8" free play
forward/backward on the crankshaft (I still can't believe it didn't
hurt
itself like that), and 2. The new engine's new clutch does NOT
chatter or
drag at all.
I think the two things are related: if the clutch is an extra 1/8"
away from the T/O bearing, it might be enough to cause drag, and,
like
suspension bushings and brake shimmy, the tiniest runout in the
flywheel/clutch could be magnified significantly by the crankshaft
moving
forward and backward, manifesting itself as one wicked
grabby/chattering
clutch.
Just one more thing to think about in this whole mess, I guess.
Michael Chaffee
mchaffee@ux1.cso.uiuc.edu
CCSO's secretary has officially disavowed any knowledge of my
actions.
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