Need clutch help (1 Viewer)

[ryukyudiver]

1995 KZJ78 w/ R151 transmission. The truck has 410,000 kms on it. Clutch pedal is randomly sticking to the floor regardless of engine running or in gear. When it’s stuck, I can lift it up with my feet and lit works for a couple shifts. Clutch master cylinder and slave cylinder were rebuilt a few weeks ago and the problem went away but have returned, though the slave squeaks like an old bed spring. Today I flushed and bled the clutch again. The problem seemed to go away with the engine off and just pumping the pedal, but then as soon as I tried to drive it the pedal stuck to the floor, truck in gear and unable to get it out of gear as the truck moved forward, I had to kill it to keep from crashing. I’ve ordered a complete clutch master cylinder that will be here in a week. Is it possible that the problem is bigger like a throw out bearing or a pressure plate? My gut tells me the master cylinder is worn and won’t take the rebuild kit and need total replacement. Has anyone had similar problems?
Thanks
Chris

 

[clintnz]

Pedal to the floor but clutch not disengaging suggests an issue with the hydraulics. If it was the throwout or pressure plate sticking the pedal would not move down much.

If the slave is making noises I would replace that too, they aren't expensive IIRC. Sticking or passing cylinders are more likely than anything binding around the actual clutch.

Cheers
Clint

 

[Tapage]

My gut tells me the master cylinder is worn and won’t take the rebuild kit and need total replacement.
Thanks
Chris

I'm with your gut ..

 

[sodafeld1]

I bang on about a motive power brake bleeder.
It bleeds hydraulics without pumping the peddle, solo exercise.
I have read that some experience hydraulic piston/seal damage from pumping the peddle when bleeding. The lack of initial fluid and pressure can cause the piston, master or slave, to travel further than what it would normally would and get stuck/stick to the cylinder. Especially on rebuilt cylinders, there maybe corrosion where the piston never traveled. Frequency of up keep maintenance of hydraulic fluid would also contribute for the cylinders to stick in position.
Hydraulic fluid attracts water, therefore creates rust.

I have only ever had to pump my hydraulic peddles if I was installing new hardware. Pumping in order to ensure that the piston can fully contract and push forward to full engagement. This is practiced before bleeding, before using the power bleeder which simply works on pressure.

They have a peaceful little video on youtubby (without thrash guitar) how to use it.

I had no idea if it was your throwout or plate. But if folks reckon it maybe your hydraulics, this may kind of explain piston seizure.

In Oz, whole new shiny aftermarket masters or slaves are not far of the price of rebuild kits, so I prefer just to get a new unit.

Since I got my motive bleeder, it has given me tremendous confidence to refresh my hydraulics anytime without needing another person. Quite a few years now, very happy with it.

 

[ryukyudiver]

I plan on doing a reverse bleed from the slave. I’m going to fill a small bike pump with fluid and push it through the system upward to remove the air.

 

[sodafeld1]

I plan on doing a reverse bleed from the slave. I’m going to fill a small bike pump with fluid and push it through the system upward to remove the air.

not sure that will help, but it is good to get familiar. May have to spend some money. Better you learn how to replace the master/ slave, spend the money on parts and tools rather than pay labour to someone else.

I buy toyota brake fluid by the 12 pack boxes. It attracts moisture once the bottle is opened.

If you want your brakes and clutch sweet you have to keep those fluids fresh, hoses, pistons and seals squeaky clean.
One has to remember that everytime you engage the clutch, you are wearing the clutch plate.

 

[ryukyudiver]

not sure that will help, but it is good to get familiar. May have to spend some money. Better you learn how to replace the master/ slave, spend the money on parts and tools rather than pay labour to someone else.

I buy toyota brake fluid by the 12 pack boxes. It attracts moisture once the bottle is opened.

If you want your brakes and clutch sweet you have to keep those fluids fresh, hoses, pistons and seals squeaky clean.
One has to remember that everytime you engage the clutch, you are wearing the clutch plate.

Oh I have a new Asin slave and cmc. Just going to bleed it from the bottom.

 

[ryukyudiver]

UPDATE: The jam nut that adjusts the distance from the pedal to the floor had come loose and shortened the throw of the clutch. A 30 second adjustment and she worked like new.