Jump to content

Release bearing freeplay?


athoose

Release bearing freeplay  

1 member has voted

  1. 1. Is your release bearing constantly (although lightly) in contact with your clutch?

    • Yes
      0
    • No
      1


Recommended Posts

  • Replies 9
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

Thanks Mike!

 

 

So the 510’s/521’s or any Datsun with an adjustable pushrod on the slave cylinder the release bearing should not be in contact with the clutch when the pedal is released. 

 

Datsuns with non adjustable slave cylinder rods will have zero clearance between the release bearing and clutch (at all times).  Free play at the pedal ensures that the master cylinder is not disengaging the clutch or putting any significant pressure on the release bearing/clutch.

Link to comment

I'll look up the amount of play on the slave push rod tonight but as long as there is some clearance, there isn't any load on the release bearing even if gently touching the PP diaphragm fingers. The adjustable ones also have a spring that pulls the clutch arm away from the clutch at rest

 

Later ones tend to retract away from the PP when released. I'll look into it but it could simply be a spring in the master pulling the piston back which hydraulically pulls the slave and pushrod back as well. I don't know.

Link to comment

Yeah my service manual just says adjust height and free play at the pedal nothing about the slave cylinder free play.  Does the 510 have adjustment on the pedal/CMC as well?

 

Checking the web yields a hotly contested debate on “air gap” (space between release bearing and clutch) vs. free play (movement of pedal before beginning clutch disengagement) on a variety of makes and models.  To further complicate the issue, some mention that the bearings need to be preloaded to a degree (by being in contact with the clutch).  No easy answers yet.

Link to comment

So I caught this important sentence in my FSM: Play due to piston and piston rod

CMCbleeding.jpg

 

 



 

Later ones tend to retract away from the PP when released. I'll look into it but it could simply be a spring in the master pulling the piston back which hydraulically pulls the slave and pushrod back as well. I don't know.

 

I seemed to recall this as well, to some extent.  That a hydraulic pull existed. 

 

Here is what I think happens ...

 

CMCpiston.jpg

 

When the piston it out (pedal disengaged) the reservoir is part of the system allowing fluid to enter the CMC bore, line, slave cylinder.  If you push on the release lever at this point, fluid will move up into the reservoir.  When the pedal/piston is pushed forward the first piston seal eliminates to reservoir from the system.  It is all free play up until this moment and there is no hydraulic push on the release lever until the reservoir is cut from the system.  Checking at the release lever it becomes rock solid once the piston seals out the reservoir and the system is pressurized.  This is the moment when load is placed on the clutch fingers.  Prior to this it's just the gravity of the fluid and the spring in the slave cylinder. 

 

In order to have the CMC keep the release bearing off the fingers (due to hydraulics) the reservoir would have to be removed from the system ....or a spring and adjustable rod would have to be added at the slave cylinder. 

 

I'm going to let the bearing ride against the fingers and see what happens.  (I definitely wouldn't do this if it came with an adjustable slave)

 

Also, if your clevis pin and clevis pin hole are badly worn you might not be adjusting out the play in the CMC(piston and rod).  Especially if you stay to factory free play specs.  Which may not allow complete disengagement of the clutch. 

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.