Went to start my 1971 240Z project car the other day and the clutch does not disengage.  Checked the forum and figured it was the Master or Slave cylinder.  Ordered and replaced both, but only get about 3/4 inch travel on the slave cylinder after bleeding the system.  What is my next step?  Looking for any answers that you all may have.  Many thanks.

 

 

14 minutes ago, afausn said:

Went to start my 1971 240Z project car the other day and the clutch does not disengage.  Checked the forum and figured it was the Master or Slave cylinder.  Ordered and replaced both, but only get about 3/4 inch travel on the slave cylinder after bleeding the system.  What is my next step?  Looking for any answers that you all may have.  Many thanks.

 

 

It would be helpful if you would provide a history of work completed since last in working order. Did you replace your clutch?

Has the car been sitting a long time?

Drove the car last summer a few times without issue.  Stored in the garage over the winter and went to start it this spring to take it out.  Clutch would not work.  No resistance felt in the clutch pedal at all.  Checked the fluid and then the forum, and figured it was the master or slave cylinder, so replaced both of them. Fluid was dark black and a bit thick.  Flushed the lines as well, and have bleed the system, but only get about 3/4 inch of travel on the slave cylinder.  Not sure what my next step is.

 

New cylinders can be bad out of the box.  Pull the dust boot off of the slave cylinder and see if there's fluid in it.  There should not be, it should be dry.

p.s. how did you bleed the system?  Maybe you didn't get all of the air out.

Edited May 31, 20205 yr by Zed Head

2 hours ago, afausn said:

Drove the car last summer a few times without issue.  Stored in the garage over the winter and went to start it this spring to take it out.  Clutch would not work.  No resistance felt in the clutch pedal at all.  Checked the fluid and then the forum, and figured it was the master or slave cylinder, so replaced both of them. Fluid was dark black and a bit thick.  Flushed the lines as well, and have bleed the system, but only get about 3/4 inch of travel on the slave cylinder.  Not sure what my next step is.

 

Your Clutch Disc is most likely rusted and stuck to the flywheel. Put it out of gear and start the engine, warm it up and charge the battery. After its warmed up shut it off. Push the car out on the street, put it in 1st gear and start the engine (with the car in gear). Get it rolling about 15 to 20 mph - push the clutch pedal to the floor, at the same time you give it some gas and pull the Emergency Brake HARD!  (to stop the rear wheels from turning - while keeping the engine running). That should break the clutch disc free of the flywheel. Might have to do it a couple times.  When it breaks free you'll feel the clutch pedal regain some resistance (feel normal).

That was what I was suspecting too.

Especially if you're near the coast in San Diego

Thanks everyone.  I need to update my profile as I am now in Rhode Island, but same issue with being close to the coast, and a lot more humid here thank in San Diego.  I got the clutch broken free as Carl Beck suggested.  Many thanks.  I then adjusted the rod on the slave cylinder and can now feel more pressure on the clutch pedal, but still not quite right.  I can start it in gear with the clutch depressed, but have trouble putting it in gear with the engine running.  Also, when I drive it, it appears that the clutch is slipping when I punch it.  Will play with it for a few days.  Step 1, re-bleed the clutch system.  I used a vacuum system to bleed it this last time.  Also, the slave cylinder came with the bleed valve installed under the hose line, where as the previous slave cylinder had the bleed valve above the hose line.  I swapped them out to be like the original was, figuring air goes up and will bleed better if it is coming off the top of the slave vice at the bottom.  Hopefully that will get me the travel that I need on the slave cylinder rod now that the clutch plate is broken free from the flywheel.  Again, thanks for helping me out.  I want to get started on my project car, and am grateful for the responses on this forum.  

Good

Yes, the bleed needs to be at the highest point

I realize it's an old thread but I often get tips that are years old so I thought I would add what worked for me. The car was sitting on jackstands for 5+ years in the Alabama humidity.

I had replaced the master, slave and line between them then did an old-fashioned 2-person bleed. The pedal was very firm but the clutch would not disengage and I couldn't grind into any gear.

This is what I did in order, not knowing which steps were helpful or not but I was eventually able to get it unstuck:

Changed the transmission fluid.

Pressed the cutch pedal down and pinned it to the floor with a stick and let it sit overnight.

Let the car fast idle for about 15 minutes to warm everything up.

Pumped the pedal twenty or so times.

Tried pushing the car in 4th with no luck.

While still warm and turned off, I put the car in first gear and bumped the starter without it starting and the car lurched forward a few feet each time. On the forth or fifth time it broke loose and didn't hear or smell any signs that I damaged anything.

Hopefully this will help someone in the future.

--Thomas

It sounds like the clutch disc was stuck (possibly due to corrosion) to the flywheel. When you disengaged the clutch, it would have released from the pressure plate, but remain stuck to the flywheel. It’s also possible that the clutch disc had difficulty sliding back from the flywheel on the transmission input shaft splines.

Next time, I would use 4th or 5th gear. In 1st gear, the engine has very little resistance due to the gearing, allowing the car to move forward too easily.

Nice to hear it was an easy fix.