Cant shift - clutch not disengaging?

[T-Bone028]

Whats up everyone, hoping someone can give me some more ideas.

 

So my 72 240Z has a 5-speed, and when the car is off, I can shift into any gear easily and without any effort. When the car is on, I can barely shift into first, if at all. And when I am able to get it into gear, it takes a herculean effort to do so. Once I get moving, I can shift into other gears with relatively easy effort, getting easier as I upshift into higher gears. If I come to a stop and sit for a while (like at a light for example) it starts all over again and I can barely get into first gear. I had to turn the car off, shift into first, and then start the car. Reverse, is a resounding grind but usually will go into gear.

 

I'm hoping that it is a clutch pedal height issue, but I have not ruled out a bad master or slave cylinder. When I tried to adjust the pedal height last weekend, I could not turn the nut on the master cylinder push rod (under the dash). It looked like there was plenty of multi-purpose grease on there and didnt look rusted together, but it did not want to move. Am I supposed to clamp down on the rod with some pliers first, and then adjust the nut to give more travel? (Should the nut go towards the front of the car, or towards the back???). When I checked the fluid level in the master cylinder reservoir, it was low. Topped it off and need to check it again to see if I have a leak.

 

 

 

Things I have not done, but will be doing this weekend if I cant solve this with a pedal adjustment.

 

1) Bleed the clutch

2) check for leaking (again)

3) Order a new master and slave cylinder

4) Shoot myself.

 

What am I not thinking of? The above diagram shows the adjusting nut...for some reason I thought there was supposed to be a lock nut as well? Open to any and all suggestions.

 

thanks,

 

T

Edited April 23, 2010 by T-Bone028

[2eighTZ4me]

No - the nut IS the locknut. Loosen it, and then spin the actual shaft of the master cyl. for you adjustment. May need a pair of small pliers to do so.

 

From what it sounds like, you have a "classic" bad slave cyl. or master cyl. Get up under the car and pull a corner of the rubber boot on the slave and see if any fluid leaks out. Also - whilst you're up under the driver compartment fiddling with the pedal adjustment, have a look at where the clutch master rod goes in to the cyl. itself (through a rubber boot) and see if you see any leakage. One or both are gone if you're losing fluid. That's supposed to be a sealed system and never lose fluid if working properly.

 

If it grinds going in to reverse, you either have 1) bad pedal adjustment, or 2) air in the system that got in past a bad seal.

 

If you find one component leaking - chances are, the other one is not far behind. Replace BOTH and save yourself the labor.

Edited April 23, 2010 by 2eighTZ4me

[T-Bone028]

Thanks 280Zme, I think I confused the master cylinder rod adjustment at the pedal, with the slave cylinder adjustment on the tranny. I know on the slave,for 70-72 it can be adjusted and there is a locknut. I just havent had a chance to get under the car with a helper to push the clutch in/out to see how much movement I'm getting at the slave cylinder rod. I'm thinking this may be the culprit, if not air in the system.

 

I'm hoping there is not a leak from the master/slave, I've heard they are notorious for leaking.

[2eighTZ4me]

On the early slave cyl's - it is exactly like the pedal. There's a locknut on the slave rod too. My guess is once you pull the boot on the slave cyl. back, you'll see fluid oozing out of there. You have heard correctly - they are notorious for leaking, and often! I'd check for leakage at the slave and master first before you enlist a helper. I'm pretty sure you'll find your problem rather quickly.

[galloguy05]

I second the bad slave cylinder. I had the SAME exact thing happen on my car and I had no experience whotsoever with clutch hydraulics. I had a friend help me ad I bought a new slave and master cylinder ad bled the clutch and I haven't had a problem since. I got the slave cylinder and master cylinder off if eBay for like 45 dollars for both.

[T-Bone028]

Well, after making adjustments at both the clutch pedal and the slave cylinder, it shifts like butter now. No grinds, no difficulty, no problems. Everything works as it should. Nice and smooth, and clutch engages/disengages nicely.

 

Unfortunately, the slave cylinder is f*&$*ed. It was moist, and I could tell it has been leaking. Surprisingly though, it didnt affect the test drive at all...which puzzles me. Oh well. I have new parts on order.

[T-Bone028]

Slave cylinder has been replaced! I had to re-use the old push rod as the new one was too long. Even after buying a new 17 mm flare wrench, I still had to use locking pliers to break free the clutch hose. I have a clutch hose in the mail just in case I need it in the future.