Good morning! I'm currently in the process of my first clutch swap and last night I attempted to bleed the clutch (installed new hydraulics while I was dug in) and although I am not getting any more air out of the line, there is no pressure building up at the pedal. When the pedal is pumped with the bleed valve open, the fluid flows back and fourth with the pedal movement, tighten the bleed screw and no pressure buildup whatsoever. Could there still be air trapped somewhere?

possibly related, the pedal itself when pushed down, like flipping a switch, will stay down and need to be pulled up to pump the master cylinder. Is this normal when there is no pressure in the system?

thank you.

 

Take a piece of clear tubing and put one end on the bleeder valve and the other in a clear bottle with the end of the tube submerged in clean brake fluid. This will show you bubbles easily.
Have an assistant pump the pedal once and then you open bleeder. Close bleeder and then release the pedal. Repeat many times.

If that doesnt work, get a vacuum bleeder

 

You will need 18 inches of clear tubing.
A flare nut or the box end of a 10 mm wrench set on nipple then attach tube. Place other end in glass jar. They are harder to knock over. Get a partner to help. Have them get ready to press the pedal in question. The trick with this process is to move the air bubbles and fluid from the bore of the master cylinder through the line and then into and out of the slave cylinder and nipple when it is turned a 1/4 turn and is opened up to allow fluid to pass. This requires a very well scripted level of communication between the two people that are bleeding the air from the system. So when the pair of you are in position. The person at the slave cylinder opens the bleed screw 1/4 of a turn and says down to the person in the cab. Then the person in the cab presses and holds the pedal down. While the pedal is being pushed down at a moderate rate of speed the person at the bleed screw watches the flow for air bubbles and fluid in the clear tube. When the person in the cab has the peddle held down they anounce "down" back to the person at the bleed screw., Then the person at the bleed screw turns the nipple back to a closed position with a lightly tightened pull of the wrench. When the nipple is closed they say, "up" and the person in the cab allows the pedal to come up. When it has come up the person in the cab anounces, "up". Once that has happened the entire cycle is repeated until only fluid is whizzing through the tube. You can count on 6 to twelve cycles and then one should take a look at the reservoir and refill it before it has depeated the fluid there in. Always stop the cycle when the nipple is in the closed condition.

To do this single handed is pysically impossible unless you use a pressure bleeder or check valves at the slave cylinder bleed valves.

Motive Products Power Bleeder works well enough but getting the cap to seal on the reservoir is a pain. Also the air pump used to put pressure in the tank is in the 5 to 15 psi range which is nothing like the pressure and positive fluid movement that you get from a properly working master cylinders piston. So the result in using a power bleeder is that the fluid movement is rather slow and you will need to be patient.

One last thing, it is a best practice to bleed the slave cylinder on your brakes that is the one furthest away from the master cylinder first and then work you way back to the shortest distance in line length in descending order. Brake fluid is great paint remover. It also has the ability to absorb water vapor from the air. If you have cast iron as the housing material used for your master and/or slave cylinders old brake fluid that has had years of time to absorb water vapor through the vent in the cap on the master cylinder will rust the bore where the piston is trying to seal and generate hydraulic pressure. The tell tail sign is that the apple cider color of the new fluid is no more and it has taken on a darker browner color which in part is the presence of rusty particles in the fluid and partly the oxidation of the fluid that is exposed to the air which is the case once it leaves the bottle. Replace this stuff completely once a year if you live in a place where it rains a lot or is very humid. When the vehicle stays in dry climates and desert locations like Nevada of Arizona at lower elevations you can prolong the change interval. Just observe its color when shopping for a used vehicle. Many second gens in CA have never had the fluid replaced and the clutch slave is cast iron.