Clutch not fully disengaging

[Diseazd]

12 minutes ago, siteunseen said:

Are you using the OE 4 speed or has it been swapped out for 5 gears? That's where the collar heights come into play.

 

4 or 5 speed trannies are same dimension. Only thing that affects collar size is the clutch. 240Z clutch requires 240Z collar...280Z clutch requires 280Z collar. 240mm flywheel requires 2plus2 collar. 

[Mark Maras]

 As I understand it the problem appears to be the clutch not fully releasing. Most clutch problems involve slipping. Yours it would seem is either in the previously mentioned collar size or in the hydraulics. I have installed new hydraulic cylinders in the past and had to adjust the M. C. push rod.  How much play in inches (easy to push) is there in the clutch pedal before you feel the resistance from the pressure plate? I'd try the M.C. pushrod adjustment. I use a sharpie on the threads to mark the original position

[siteunseen]

Wouldn't a 5 speed have a different collar heighth than a '71 240Z's 4 speed?

[Cameron McDonald]

17 minutes ago, Mark Maras said:

 As I understand it the problem appears to be the clutch not fully releasing. Most clutch problems involve slipping. Yours it would seem is either in the previously mentioned collar size or in the hydraulics. I have installed new hydraulic cylinders in the past and had to adjust the M. C. push rod.  How much play in inches (easy to push) is there in the clutch pedal before you feel the resistance from the pressure plate? I'd try the M.C. pushrod adjustment. I use a sharpie on the threads to mark the original position

Ok thanks I'll try this later on when the sun goes down a bit! If there is alot of travel in the pedal before I start to feel resistance should I adjust until the point of no play?? If theres already no play should I still try adjusting?

[Diseazd]

33 minutes ago, siteunseen said:

Wouldn't a 5 speed have a different collar heighth than a '71 240Z's 4 speed?

No Site..... all 240Z trannies and 280Z and ZX trannies are the exact same dimensions. All can use either a 240Z clutch or a 280Z clutch or in the case of a 240mm flywheel, they would use a 2 plus 2 clutch. The only thing that affects the collar, is which clutch you use. 240Z clutch.....use 240Z collar. 280Z clutch....use 280Z collar. 2plus2 clutch uses 2plus2 collar. I like to use 240Z clutches in all my Z’s except the ones with 240mm flywheel (2plus2 collar). That way, I keep everything simple. If you get a new clutch, just ask for the collar that fits that clutch. I would use Motorsports because you can talk to someone and make sure they ship you a 240Z clutch, 240Z collar and throw out bearing as a package. All throwout bearings are the same for all three clutches.

 

Edited June 24, 2019 by Diseazd

[Mark Maras]

54 minutes ago, Cameron McDonald said:

Ok thanks I'll try this later on when the sun goes down a bit! If there is alot of travel in the pedal before I start to feel resistance should I adjust until the point of no play?? If theres already no play should I still try adjusting?

 You'll want a little free play (1" or so) at the top of the pedal but a worn clevis pin in pedal pivot can make it feel like there's free play but there really isn't. The best way to check the free play is at the slave cylinder. After adjusting the MC pushrod so there's about an inch of free play at the top of the pedal stroke (assuming the pedal is at the right height) disconnect the slave cylinder spring and push on the end of the release (throw-out) fork. There should be a little (1/8"-3/16" free play in the release fork. That ensures the clutch will release completely and not slip.

[Cameron McDonald]

1 hour ago, Mark Maras said:

 You'll want a little free play (1" or so) at the top of the pedal but a worn clevis pin in pedal pivot can make it feel like there's free play but there really isn't. The best way to check the free play is at the slave cylinder. After adjusting the MC pushrod so there's about an inch of free play at the top of the pedal stroke (assuming the pedal is at the right height) disconnect the slave cylinder spring and push on the end of the release (throw-out) fork. There should be a little (1/8"-3/16" free play in the release fork. That ensures the clutch will release completely and not slip.

Ya mc is adjusted correctly already and theres proper clearance at the slave. I think I'm gunna replace the clutch itself and see where that gets me 

[Zed Head]

The collar needs to match the height (thickness) of the pressure plate.  With aftermarket parts you can't really define by 240Z, 280Z, Zx, 2+2, etc.

https://www.rockauto.com/en/catalog/nissan,1976,280z,2.8l+l6,1209226,transmission-manual,clutch+pressure+plate,1988

[240Znomad]

9 hours ago, Cameron McDonald said:

Ok thanks I'll try this later on when the sun goes down a bit! If there is alot of travel in the pedal before I start to feel resistance should I adjust until the point of no play?? If theres already no play should I still try adjusting?

When I got my clutch working (after sitting for 28 years), I had a lot of travel in the pedal as well before it starting to move the slave cylinder push rod.  It turned out that the clevis pin that connects the clutch pedal to the master clutch cylinder was all worn out.  Instead of being a nice round hole it was worn down to a long oblong/oval hole.  In addition, the clevis pin that fit into that hole was worn completely down to almost nothing.  I removed the clutch pedal and took it to a shop to have the ovalled out hole welded up and re-drilled.  Then I replaced the clevis pin with a new one.  Mine was worn so badly that I was probably losing half the pedal travel before it actually starting to move the master cylinder.

Edited June 25, 2019 by 240Znomad

[EuroDat]

Hey guys, Why are we talking about replacing the clutch. His problem is the clutch does not disengage properly. If it was slipping, then I would suspect the clutch.

A list of things that can cause a dragging clutch

- Clutch master cylinder push-rod wear and adjustment.

- Slave cylinder push-rod wear and adjustment. You should have the adjustable push-rod type with the return spring.

- Worn out master cylinder and/or slave cylinder rubbers. The slave cylinder you should see leaking fluid at thr push-rod. If the primary piston cup in the master cylinder is leaking. It will leak fluid back to the master cylinder resiviour and the clutch will loose travel. You will notice this in 1st and reverse firstly because they are standing start applications. You can check this by depressing the clutch peddle and holding it on the floor while someone watches the slave cylinder push-rod. If the clutch fork slowly returns then you have a laeking primary rubber cup in the master cylinder.

Other things that will cause a dragging clutch and require removing the transmission to inspect and replace. They are not so common, but do occur occasionally.

- Dry spigot beering in the end of the crankshaft. A very dry spigot bearing will drag the input shaft with the crankshaft.

- Dry or rusted input shaft splines. When the pressure plate disengages the clutch plate, the clutch plate moves along the splines so to release it from the flywheel. If the clutch plates movement is restricted, it will disengage fully from the pressure plate, but not from the flywheel.

Don't just assume its right. Follow the FSM for adjusting the master and slave cylinder push-rods.

I posted the position of the clutcgh fork in relaxed and depressed positions. I can't remember of the top of my head and I'm not really closeby to civilisation atm. Ill try to find them. That would confirm the correct travel and the collar is correct or not.

I would be doing these checks first before taking any steps to remove the transmission.

 

Ok, I found the other thread.

 

Edited June 25, 2019 by EuroDat
Found other thread

[Diseazd]

15 hours ago, Patcon said:

When you do the clutch be sure the throw bearing and collar stack to the proper height. Maybe some one can link to it for you. If the stacked height is wrong it can cause similar issues

 

[Diseazd]

16 hours ago, Cameron McDonald said:

I just purchased the vehicle it has always done it in my case but I dont know for how long. A friend recommended a test I can do to see if it's the just clutch itself needs replacing so when I get home I'll try that and know a little more

.........did it ever work correctly for the previous owner, or did he replace the clutch with the wrong parts, then sold it because he couldn’t fix the slipping problem?