clutch fork swap?

[Diseazd]

R u sure about 8 3/4? Seems like 7 inches comes to mind on the 240....just from memory.

[anthony_c]

yep

[Diseazd]

I give up......seems like it's got to be in the master cylinder or a bleed problem......you've already tried two slave cylinders. What else could it be?

[anthony_c]

my suspicion is that everything is working as designed, but the current iteration of slave cylinders available for the 280z is the wrong design. (wrong pushrod, wrong bore, or maybe even offset mounting points). but short of buying one from every vendor and manufacturer i'm unable to find one that will work, so i'm going with your original suggestion.

swap out the fork and slave for the adjustable 240 version and move on to the next problem.

[EuroDat]

swap out the fork and slave for the adjustable 240 version and move on to the next problem.

I don't thick that will fix your problem. It might help a bit, but you could take all the free play out of the slave cylinder. That would mean the throw out bearing is pushing constantly against the pressure plate and it could cause it to slip.

There must be something wrong with the diameter ratio master/slave being slave bore too big maybe.

To make it adjustable, all you need is a long 5/16" bolt, a cap nut (thread tapped through it) and drill a hole in your fork.

Chas

[Zed Head]

There are only two basic things you need to work with on the clutch hydraulic system - starting point and travel. The travel is determined by how the master cylinder's movement is transferred to the slave cylinder. The starting point is determine by the mechanical components. I don't know the spec. on travel but the posts above suggest it's about 35 mm or 1 3/8". If you're only seeing 1/2" of travel, it's either because the rod from the pedal to the master cylinder is moving without pushing the master cylinder piston, or the master cylinder piston is moving without pushing fluid. The slave cylinder is self-adjusting due to the internal spring, so it's not really an issue unless it's leaking.

I left some detail out but that would be my basic starting point. To reiterate - if the slave cylinder is not leaking, it's not your problem. It only responds to the fluid being pushed in to it. If your not getting full travel, it's because the mechanical linkage is not adjusted correctly or the master cylinder is leaking internally.

Blue must have been having a bad day. He seems yo be ignoring the fact that the specs. that the Asian companies use are set by the their "Western" company contractual counterparts. In other words, if your "Made in China" part has problems it's because your American company is making profit at your expense. There are many many high quality products made in Asia. Nest time you're looking at your fantastic picture quality big screen TV, amazed at today's' modern technology, look at where it was made. Probably China.

[Diseazd]

Zed....What you just said makes a lot of sense....If the pressure plate, collar, arm and slave cylinder are all 280z stuff, the system should work. The one thing that is a question mark is why is the slave cylinder linkage not moving enough? The only thing left is the clutch master cylinder. If the distance pushed on the piston in the M/C isn't enough to push the needed fluid to push the piston in the slave cylinder, it would be possible that the M/C is wrong, or that there is air in the system.....make sense? He's confirmed measurements are correct on pressure plate and collar, and has tried two different slave cylinders. If the push rod in the slave cylinder is touching the clutch arm now, then an adjustable 240Z slave cylinder isn't going to give you a longer push than what you have now. Awconroy.....Are you sure the clutch master cylinder is correct? You said it was bled....try it again. What else could it be?

Edited November 27, 2013 by Diseazd

[anthony_c]

the mc was not leaking so i did not replace it. it was working prior to replacing the clutch and slave.

it seems the only way to test re-bleeding the lines or replacing the master is to put it all back together (and hope it doesnt have to come out again).

my current thought is that the slave pushrod is too short, allowing the slave piston to advance part way through cylinder before i even step on the pedal. it is effecively self-adjusting like it is supposed to, but for the wrong reason.

@diseazed: the car and the clutch parts are still sitting on chuck's frame alignment rig, and i dont think i can leave it there too much longer. i need to present him a definate fix, or at least a permanent work-around.

Edited November 27, 2013 by awconroy

[Diseazd]

Awconroy.....Sorry...I'm stumped....it's possible I guess that the pushrod is too short. I'm not familiar with the 280 slave cylinder....guess the piston is spring loaded to allow for auto adjustment. You could use the early slave cylinder with adjustment....it may or may not solve your problem. You could order a early slave cylinder and clutch fork. Give it a try....at least you'll know the travel of the slave cylinder piston should be right

[240260280z]

well, before we all start blaming a nation of several billion people for my clutch problems...this slave cylinder was purchased from Courtesy Nissan.

I also bought one from Arizona Z and it was identical.

Not blaming, just stating facts.... I know a little about Chinese manufacturing..... and their products get into many supply chains sadly.

EDIT See next post for possible solution

Edited November 27, 2013 by Blue

[240260280z]

I re-read your post and the "push rod on the master is fully extended" could be the culprit. You may have reduced the master's stroke.

Think of the plunger in the master; for it to give maximum stroke, that plunger has to be back towards the firewall as a starting point.... this frame of reference may help.

[EuroDat]

I think I would start all over and begin with adjusting the pedal travel, make sure hats right then move to the slave cylinder.

Like Blue said, if the master cylinder is not returning completly, it could be all your troubles there.

Then check the free travel on the slave push rod and make a new one or use the original if its the better length. Just make sure you have between 5 to 10mm to allow for clutch plate wear.

Chas