azerite

I pieced my car together and for the life of me can't solve my clutch problems. I replaced everything on the clutch (disc, throw out bearing needle bearing, the bearings in the fork, and resurfaced the flywheel). I bled the clutch 3 different ways, pressure bled, used a 200ml mightyvac to force fluid from the bottom, and the method from another member to push the fork in and then pump the fluid.

The problem i experience is that the clutch pedal sticks to the floor. The best results come from pushing the fork in reverse and pumping the pedal, but as soon as i engage a gear and push too deeply on the clutch pedal it doesn't come back unless i coax it back. If i drive for 30 minutes or so, it's weird it's like resistance builds in the pedal, and there are times when it works great, then randomly sinks again.

I have a new master cylinder, new soft/hard line, new slave cylinder and i pressurized via the brake reservoir up to 20psi and no leaks. Anybody have any ideas? I think the slave might have failed internally though it was new (FTE unit). When i press the clutch, i can hear a squeeking noise as the clutch is pressed off the flywheel.

Dan Martinic

MAGK944

azerite

I did all 4. The problem isn't so much that the pedal sinks, it's that it's not returning of it's own force.

azerite

The spring on the pedal (the big blue one) is still there and acts as the cantilever. If i look at the bell housing when i press the pedal, it moves the rod on the slave cylinder. The rod is adjusted to the same length as removal.
Is it possible it's the bearings that hold the fork and that those don't easily move? The clutch when depressed moves the rod in the slave, but the pedal doesn't readily pop back. I can drive the car if i press the clutch and keep my foot on it and gently the pedal will come back, but not quickly. Something is definitely stuck in the system, just can't figure out what. I don't think it's air per se, unless it's sucking in air somewhere on the return stroke (master/slave cylinders).

Could the seal be blown on one of the cylinders on a new unit?

951and944S

With Fluid in brake reservoir well past the minimum level that will cover the feed hose to the clutch master, raise pedal by hand to normal height,
lay under car with a large flat screwdriver with your body positioned where you are looking at the inspection hole/lever/slave pin.
Place the blade between the fork and the casting and pry the fork opposite it's direction that normally releases the clutch.
Release pressure and allow fork to return slowly.
Repeat several times.
Report back,

T

azerite

MAGK944

azerite

951and944S

No, should line up.

I have seen one instance where a racer so frustrated with trying to bleed pedal to not load up and go home from a long road trip (Sebring) that he asked me to try the method I described.

It worked for a lap or two but the throw out bearing lock ring was broken on the pressure plate, the resulting vibration would just re-aerate the fluid within 5 minutes.

You have to perform the procedure I described until you don't have any more "swooshing" sound of bubbles/air.

Is your metal tube/rubber hose new....?

I have seen the interior wall of the rubber section peel away internally which caused a one way check valve in the line.

Good luck.

T

kirkandorules

I had trouble getting mine bled properly when pressurizing the reservoir at 20psi, the tank dipped below the top (blue? can't remember) tube too quickly. Had much better luck with my Motive set at 10psi or so.

azerite

yes the soft line is new as well. The only thing i didn't change on the entire system is the hard line that goes to the slave (which should be ok since it's metal anyway?)

That's what originally led me to do the work (soft line), the original was bulged out and i couldn't shift. I think it may be the fork. I pressed in the slave piston a few times, and the swoosh i was referring to was liquid. If i press it back fast and hard with a small prybar, you can only hear liquid. I think the problem is the fork, it's not exactly center on the entire travel path, and as a result it pulls the piston slightly and creates resistance on the way back? I know it sounds like a tinfoil hat idea. The lock ring on the throw out bearing is new, and i don't feel any vibration except when i engage the clutch (the clutch is spring type so there is some vibration in the pedal when i press it in to engage).

The only tell tale sign is a squeaking. After i lift the car, press the piston in like T suggested, there is squeaking, can't figure out if it's the slave, or something else.
I'll bleed again just in case.

Dan Martinic

I didn't get a proper bleed until I used my Motive (at the recommended 15psi) and had my son press the pedal while the system was pressurized and I was cracking the bleed bolt. Only when I did it this way did the pedal fully return.

That fork action does sound funny though. I can't see why a fork wouldn't travel straight? It would have to be loose on its bearings or the pin loose in the bore; either way, you'd have a loose fork, no?

951and944S

So after that's done, did you use your hand, just manually lift the pedal and pump with your hand about 1 inch travel only.
About every 4-5 times, take the pedal to the top one pump and go back to pumping the 1 inch stroke.
Do that a few times after the stroking of the fork like you already did.

As long as fluid is above the blue feed hose, I can't see you having air in the system.

I have never bled a clutch on a system similar to 944 in the conventional way described here in 25 years.

I have flushed by opening the bleeder, but never touched a bleeder for air in system.

T

azerite

I had to do the exact same thing to flush the entire line out. I held at 15, and then manually pumped in order to pressurize when bleeding. It worked, but not quite. I had to do what T suggested and do the 1 inch pumps at the bottom then full strokes etc. That really firmed up the pedal. That only lasted for about a day though. The next day as soon as i took it out, the pedal stuck. It didn't fall, you could feel it actuate, but it didn't pop back up. Then after a 20 minute drive, the pedal started working like there was nothing in the line. That's why i can't pinpoint, it's not a consistent symptom.