advice on adjusting clutch slave cylinder

[deadflo]

A couple months ago, I had a bearing kit put in my 71 4 speed tranny .

After i got it back from the shop, I had occaisonal "crucnhing" when shifting into reverse. The shop adjusted the rod on the slave cylander so the crunching went away.I noticed the clutch pedal action felt firmer as well. Yesterday i noticed I am beginning to get clutch slippage.

Note that I had the shop inspect my clutch when it was out and they said it is fine.

I hear that it is very liklely the slippage is caused by the slave cylinder being adjusted too much in the other direction.

I want to adjust the rod on the slave myself. I see it has a lock nut and an adjustment nut, but I'd like some advice before jumping into it...

has anyone dealth with this before??

[dogma420]

its pretty easy.

have 2 wrenches, I think it was a 10 mm and a 9mm or something like that...also a thicker than normal headed standard screw driver.

when a clutch is new, and properly adjusted, the nuts for adjustment are at the closest they are going to be to the slave body; the farther from the slave body the adjusting nuts are (and hence the clutch fork position) the older the clutch is (and the more it has been adjusted).

Essentially, when you first feel the clutch STARTING to slip, you can loosen the lock nut, hold the adjusting nut with a wrench, and using the screwdriver on the shaft, maybe try 1 full turn, or maybe 2. A clutch in good shape isn't going to need much adjustment to eliminate the slip. Then I always just go drive it and test it, to see if this adjustment is perfect.

As a side note, I just put a 78 5 speed in my 72 240z, and from 75 on, the slave cylinder is self adjusting, the shaft has no adjustment, and there is a spring inside the slave that automatically adjusts the clutch...doesn't work with a 4 speed tranny/clutch (pre 75)....

Later!

[deadflo]

Ok!, so I actually hold the adjusting nut as well and adjust with a screwdriver?

[mperdue]

Sorry if this is a dumb question, but what exactly is clutch slipping and how do you know it's slipping? I guess I don't understand how the whole clutch assembly works enough to understand the explanations I read on the internet after searching Google. Thanks,

Michael

[ChrisA]

Sorry if this is a dumb question, but what exactly is clutch slipping and how do you know it's slipping? I guess I don't understand how the whole clutch assembly works enough to understand the explanations I read on the internet after searching Google. Thanks,

Michael

Hey Michael, when you push the throttle down, the engine increases speed but the car doesnt go faster. You are actually slipping the flywheel against the friction disc of the clutch pack. They are not mated and cant transfer the rotation of the engine to the transmission. The tach needle will climb in a non proportionate amount compared to the speedo.

Anyone else have anything else?

Chris

[deadflo]

In my case the symptom Im seeing is my engine revving without feeling an increase in the actual speed of the vehicle. Thus the clutch is not fully engaging the transmission to the engine in the drivetrain.

[Bambikiller240]

........... and from 75 on, the slave cylinder is self adjusting, the shaft has no adjustment, and there is a spring inside the slave that automatically adjusts the clutch...doesn't work with a 4 speed tranny/clutch (pre 75)....

Later!

Actually, from 73 forward the clutch is self adjusting. The clutch fork is different, and the slave cylinder is different for PRE 1973 Z transmissions, than for POST 1972.

70-72 adjustment is a manual process.

73-78 adjustment is automatic

Check your FSM's boys & girls

[mperdue]

Hey Michael, when you push the throttle down, the engine increases speed but the car doesnt go faster. You are actually slipping the flywheel against the friction disc of the clutch pack. They are not mated and cant transfer the rotation of the engine to the transmission. The tach needle will climb in a non proportionate amount compared to the speedo.

Anyone else have anything else?

Chris

Thanks Chris, that makes sense to me. I thought it had something to do with shifting gears.

Michael

[Bambikiller240]

In my case the symptom Im seeing is my engine revving without feeling an increase in the actual speed of the vehicle. Thus the clutch is not fully engaging the transmission to the engine in the drivetrain.

On "some" cars you will run out of adjustment at the slave cylinder and still have problems with slippage.

In many of these cases the problem stems from the clutch pedal itself. There is a hole in the pedal arm that the clutch master cylinder linkage attaches to with a hardened clevis pin and over the years the clevis wears the round hole in the pedal arm into an oblong shape which causes motion of the pedal to be wasted as the slop in the (now) oblong hole is taken up so that he master cylinder linkage can start operating the hydraulic system to actually create movement of the slave cylinder. Thus the master cylinder doesn't create the full pressure needed to make the slave move the full distance it needs to move the adjustment rod.

I experienced this problem after a complete new clutch system (disc, p/p, t.o. bearing, m/c, & slave) installation when I first purchased my present Z, I discovered the oblong hole in the pedal and sent the pedal out, to have a steel bushing with the correct 8mm hole bronze welded into the pedal arm to correct the oblong hole issue. Full movement restored, no problems in 4yrs+.

[ChrisA]

...over the years the clevis wears the round hole in the pedal arm into an oblong shape which causes motion of the pedal to be wasted...

Very good info Carl, that problem had never crossed my mind.

Chris

[Bambikiller240]

Very good info Carl, that problem had never crossed my mind.

Chris

Hadn't crossed my mind either. I emailed the IZCC list and Kim Blough of Idaho Z Car put me on the right trail.

[Fun_in_my_z]

Will a clutch from say a 73 or 74 interchange with a 71?

Self ajusting slave cylinders sound so much better .