No clutch peddle pressure

[peng155]

Hi Folks,

Quick question for ya all...

I started working on my 71 z the other day.... It's been about 5 years or so since I last drove it, When I put it under the car cover the Z was drivable, but when I went and started it up the other day and pressed on the clutch... the peddle went straight to the floor board with very little pressure needed... I checked under the car, and I saw no signs of any fluid leaks..

I checked the clutch cylinder and it was full, I'm planning on bleeding, and replacing the old clutch fluid tomorrow with new.... but I was wondering if anyone knew is it possible for either the clutch main, or slave cylinder seals to leak from sitting so long and lack of use, or could the system just develop air in the system from lack of use?

I know I've had the slave cylinder replaced already due to it leaking, and I pretty sure it has less then 3k miles on it, but it's probably about 7 years old... anyone have any ideas?

Thanks

Edited August 24, 2013 by peng155

[Pomorza]

Phil

Yes it is possible that air got into your system due to non use. I would start by changing and bleeding the system and seeing what happens. My friends 240Z sat for nearly a decade with a brand new master and slave (he did it right before he put it in storage) and when he went to move it the other day he had no pedal at all.

On a related note, if you let your car sit so long I would probably look into changing the gasoline and cleaning the lines - unless you used some sort of gas storage addative. Modern fuel has a tendancy of "splitting" and getting all sorts of gunk everywhere (ethanol fuel anyway). Check the oil and the radiator fluid also, they might need a change.

Hope that helps

Jan

[Bruce Palmer]

Wouldn't be at all surprised if the seals aren't sealing anymore just from sitting..... Try bleeding and see if anything comes out of the slave. If it does and the fluid is dirty do a complete replace with new. About once a year brake and clutch hydraulics should be drained and replenished with new uncontaminated fluid. Anyone on here actually do that?

[EuroDat]

I would try a simple test before doing anything. Get someone to push the clutch peddle to the floor and watch the slave cylinder. If it doesn't more, than your problem isat the clutch master cylinder.

My guess is a collapsed primary cup in your master cylinder. Its probably deteriorated over the time it was sitting still. Gunk and corrosion gather in the bottom of the cylinder when sitting still and tears the cup apart.

Replacing the fluid might help, but I think you will eventually need a new clutch MC.

Chas

[EuroDat]

If the slave cylinder is working correctly. Some other things that cause prevent clutch disengaging. Siezed spigot bearing or a broken/cracked clutch fork.

Ive seen a cracked clutch fork in a Datsun 180B. It cracked at the pivot point inside the bell housing. Took a long time to find the problem. Afterwards we realised we could have seen it by removing the rubber boot and looking at it with a mirror.

I have only seen it on this 180B, but I have heard of it happening to other people.

Chas

[peng155]

Hi Folks,

Thanks for the replies and info.... Tried bleeding the clutch system, and that didn't fix the problem, so I'll probably go ahead and replace both the master clutch, and slave unit.

I was able to flush the system using my vacuum bleeder, but I wasn't able to get a steady stream of fluid, it was a mix of fluid and air.. so instead of screwing around with it, I'll just replace both units and hope that takes care of the problem... unless someone thinks it could be something else.

Thanks

[EuroDat]

Phil,

If you are going all the way and replacing both units. Buy a new hose section as well. Altough it lasts longer than the cylinder cups, its probably still original and been there since 1970. The inner rubber section is probably spongy and flexing with every press of the pedal by now and making the clutch feel a little sprongy as well.

Chas

[Captain_Zeros]

On top of that, a 40 year old rubber hydraulic hose is long overdue to split and spray your precious fluids everywhere.

Always replace the flex line when you're replacing cylinders!

[peng155]

Hey Guy's

Once again thanks for the advice and info.. When you guy's talk about replacing the hose section.... I'm guessing that you're talking about the hose section that connects from the hard line to the slave... correct??

On another note.. I was doing some price comparison shopping for the master, and slave I notice that one vendor has the master, and slave with hose section in a kit for about $98.00, another vendor sells them separate for about about $140.00 total. I've always believed in doing it right the first time using quality parts. I'm not saying that one vendors part is inferior over the other, but a price difference of 40 bucks... well 40 bucks is 40 bucks. Do you guy's think spending the extra 40 bucks get me anything... Other than a more expensive master, and slave unit??

Thanks

Edited August 25, 2013 by peng155

[EuroDat]

Phil,

Have you tried Rock Auto?

I have used Rock Auto and had no trouble so far with the brand Beck/Arnley. Just did a quick check and all three parts cost less than $50.00

Maybe others members have experience with other brands?

1977 NISSAN 280Z Transmission-Manual Parts

Chas

Edit: Just realised you have a series 1. You will need an adjustable push rod on the slave cylinder or use your old one and the return spring.

http://www.rockauto.com/catalog/x,carcode,1209147,pgname,Transmission-Manual

Edited August 25, 2013 by EuroDat