[Redheadedpimp69]

Hey everybody,

I'd like to start this out with an apology. I searched the forums and couldn't find anything matching my problem.

First starts, it's a 1981 280zx.
About a month ago, I was having a little bit of a clutch issue where it felt like I had to press the clutch pedal in way harder than I needed to to be able to get it to shift into gears. I did all my normal checks on the master, and slave. Nothing turned up so upon consulting with a friend he recommended that it was probably my throw out bearing.
Him and I replaced it, upon doing so, everything went perfectly. ( I only replaced the throwout bearing, not the clutch, I understand that is a no no, but I replaced the clutch without the throwout bearing due to having received the wrong part about a year ago. So I couldn't rationalize spending another $150 to replace the clutch again if I didn't need to.)
Replacing the throw out bearing fix the issue for about a week.
Snap to a week later, I pull into Target and park. Attempting to put it into first with the car off, nothing. Couldn't get the shifter into position. Couldn't move around at all. Seemed like a problem, I decided that the only thing I could do before calling a tow truck was jacking it up and replacing the slave cylinder in the parking lot. ( Not that it's really worth noting, but I ended up replacing it in a northern downpour and veritably ruined my entire week)
While bleeding the clutch with somebody else pumping the pedal, the piston exploded in the slave cylinder. Just popped right out of there.
I figured that maybe my issue had been that the throw out bearing that I replaced my old one with was slightly longer for the recommendation by the manufacturer of the clutch plate that I bought.
Due to this, I thought that maybe my adjustable slave cylinder push rod may have been the wrong length. ( I'm not sure, but I believe that the adjustable push rod was only on 240z so I don't know why I have one on mine. But I can't use a normal push rod because the clutch fork that I have has the extra wide notch that only supports the adjustable one.
So attempted to adjust it. And shared the darn thing right in half because those nuts were rusted to all ****.
Snap to another week later, the new adjustable rod arrives along with a slave cylinder for a 240z.
The slave was something that I would need to replace anyways because the last one busted apart, so I adjusted it and installed the 240z slave along with the push rod.
While bleeding the clutch for the second time, at one point, the pedal froze in the up position and would not move down at all. As the novice mechanic that I am, knowing that I just replaced the slave cylinder, I decided to replace the master cylinder. Upon replacing the master cylinder, I went to bleed it again. This time, I bled and bled and bled, and now, you push the clutch pedal down and it does not return no matter how much air you get out of the system.
I called O'Reilly's who has a guy who's pretty familiar with Datsuns and he told me to pull the master out and bench bleed it. So I did that about an hour ago. Bench bled it and reinstalled it and then bled the whole system again and the problem persists. You can press down on the pedal but it will not return to you.

Also, after replacing the master cylinder and not having any more success, I also got a recommendation from a friend that I might have a collapsed line. So I replaced the rubber clutch hose as well.

Another note, the system does not have any evident leaks. Everything seems nice and snug.

At this point, I'm at a loss and don't know what to do. I'm back and forth between wondering if I got a bum part from O'Reilly's or if my issue is actually internal to the transmission ( throw up bearing, pressure plate, clutch)

Does anybody have any ideas? Feel free to talk to me like an idiot because I sure feel like one and I'm praying that I just missed something really stupid because I am struggling to keep my chin up.

Also, I understand that you should never replace the clutch without replacing the throwout bearing but I didn't have a throw up bearing available to me that would fit in the car and the one that came with the clutch wasn't correct for my car and at the time it was my daily driver so I couldn't help it. In the future I will not do that.

 

[pilgrim]

I'm not sure about this, but I doubt the problem is in the master cylinder especially if it behaved normally during the bleeding process.

I've had the clutch pedal stay down and not return to its normal position (1983 280ZX), but that happened when the slave cylinder went bad and stuck in the extended (pedal depressed) position.

Memory tells me that somewhere in this forum there was a discussion of discovering two different throwout bearings of different lengths. Might be worth searching to see if you can find that thread. If the car did drive OK for a few days, I would think the TO bearing is probably OK.

Might the clutch lever which contacts the TO bearing be installed incorrectly and moving around?

 

[Redheadedpimp69]

I made sure that the clutch fork was properly attached to the TO bearing. Also, through the clutch fork hole, it looks like it's still attached properly.

With the slave off, I can disengage and engage the clutch by hand.

I read through the TO bearing thread and I believe I installed the proper one for the clutch.

At this point, my biggest thought is that the new slave is faulty.

 

[pilgrim]

At this point, my biggest thought is that the new slave is faulty.

That would be both the easiest and cheapest fix if it works out!

 

[Redheadedpimp69]

I will have to order them. It'll be a few weeks until I can install them due to leaving town but I'll post results once I return.

 

[Redheadedpimp69]

Scratch waiting a couple of weeks. Something lit a fire under me and I decided to throw everything I've got at it tonight.

I replaced the slave cylinder with one for O'Reilly's. I adjusted the adjustable rod on the slave cylinder to a shorter length based on the previous length of the rod that I had. ( Small adjustment, but notable).

I bled and bled and bled and bled and bled with no success.

At this point, I had almost assuredly decided that the master cylinder was the issue. I removed the brand new installed master cylinder and compared it to the old one. The new master cylinder had a piston rod with a huge amount of play in all directions and forward and backward movement as well, only a few millimeters but enough to make it feel wonky especially compared to the old master cylinder whose piston rod which attaches to the back of the clutch pedal was firm and deliberate. Very little unwanted lash and did not easily move left or right. Ford and backwards movement was all that it did.

With this newfound knowledge that could have been found much earlier had I been an attentive mechanic, I bench bled the old master cylinder and reinstalled it. After about 10 minutes of bleeding and pumping, the pedal finally firmed up and now seems to be working properly. As it is nearly midnight, I have not put the car back down and taken it on a test drive. ( It is notable that that's not just because of the hour but because I'm terrified of it breaking. And not terrified because it would leave me stranded, but terrified because I don't think I have the willpower to not off myself if it breaks again.)

So with that, the problem appears to be fixed pending retest.

I'm not sure if a thread in this forum was entirely necessary but I hope that it might help some new mechanic like I in the future.

 

[Redheadedpimp69]

Annnd disregard.

Upon retest, I cannot shift into any gear.
Clutch pedal goes down and comes back up but now it does not seem to want to shift into any gear. While trying to put it in reverse, I get a nice pleasant grinding transmission sound.

 

[pilgrim]

Possibly adjustment of the rod length. Sounds like it's not moving the clutch TO bearing far enough to completely disengage.