QuestionQUESTION: Have replaced M/C, S/C and line, but cannot bleed the system on my 68 Midget (72 engine). I have pumped plenty of fluid through the system without air bubbles, but cannot get the pedal to move the piston on the slave cylinder.
I read a fix that suggested removing the bleed nipple and pumping the pedal by hand, but cannot imagine how this would work with a left hand drive car.
Is there a simple method of doing this - special pump; special tools; etc.?
Additionally, the car should be fitted with a 3.000 inch slave cylinder piston link, is the 3.000 inch measured from the center of the hole or overall length?
ANSWER: Hi Peter,
If the master cylinder is not moving the slave piston, the master is not doing anything and you can not bleed the system unless the master is pumping something.
Do this, loosen the fill cap and open the bleeder on the slave and put a pan or jar under it and watch for fluid. Do not touch the clutch pedal. Fluid should start dripping and running out of the bleeder valve. If you have a plastic tube to slip over the bleeder valve to watch the fluid come out, that would be better but not necessary.
If no fluid drains out, then the master cylinder piston is not returning to it's correct position for some reason. Either the pedal is holding it depressed or the piston is stuck in the bore. The piston in the master must return all the way for any fluid to enter the master cylinder from the reservoir. When the piston is in this position there is an open path for fluid to run from the reservoir to the slave bleeder valve. Check to see if the pedal has a pedal return spring and that the pedal is not sticking.
If you get fluid draining out of the bleeder valve watch the level in the reservoir closely and when the reservoir is down to half, close the bleeder valve and the system is usually bled and you should get a firm pedal with a few pumps of the pedal.
Let me know,
Howard
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QUESTION: Did what you suggested. Poured about half a pint of fluid through the MC to the SC. It doesn't flow fast, so if there is any air trapped I don't think it's going to be pushed out. Regardless, I tightened up the bleed nipple but still no movement when I press the pedal. Everythng else seems fine; pedal spring is good; nothing is sticking.
ANSWER: Try this, with the master cylinder reservoir only half full use a pry bar and pry the lever on the bell housing so as to force the slave cylinder operating rod into the slave cylinder all the way. Then push the clutch pedal down and let it up very slowly and repeat pressing the pedal down and letting it up very slowly. After three or four pumps of the pedal like this if you still have no resistance you need another master cylinder.
The force of pushing the slave piston in pushes the fluid up into the master cylinder and on into the reservoir and taking any air in the system with it. The slow release of the pedal is necessary so that the master cylinder piston can draw new fluid from the reservoir without drawing air in past the piston seal.
Let me know.
Howard
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QUESTION: Didn't need a pry bar to push the piston into the slave cylinder, could do it by hand, but still no pressure. However, I now have it fixed. Because I have a flexible hose connected directly between the two cylinders, I disconnected the slave cylinder from the gbox and placed it on top of the valve cover in a tray. This puts the slave cylinder higher than the master cylinder, and pressing the pedal quickly expels the air. I did have one problem; the new slave cylinder (from VictoriaBritish) doesn't have a retaining ring so the first time I did this the piston came out of the cylinder (along with all the fluid). After re-installing the piston I had to hold the operating rod hard against the piston whilst bleeding. Now, after re-installing all the parts, I find the starter is no longer working (my next project).
AnswerHi Peter,
Glad to hear you got it fixed. As for the starter, check for power on the White w/red tracer wire from the ignition switch to the starter solenoid when you are in the start position. If you do have power on that wire then you need to check for power at the solenoid battery post and check for good grounds, Engine to frame and battery to body. There is no relay in the circuit.
Howard
