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Hot Rods M21 clutch problems!

Discussion in 'The Hokey Ass Message Board' started by Camron.est1991, May 28, 2017.

  1. Camron.est1991
    Joined: May 28, 2017
    Posts: 19

    Camron.est1991

    Hey guys so I am having clutch issues, I bought a brand new zoom clutch for my m21, a new master a new slave cylinder and the clutch still won't work. I got the truck from my grandpa after he past and the truck sat for a while so everything needed to be redone, the clutch set up he had on it was working but the clutch was pretty well burnt so I got a new clutch, m21 came out of a 64-65 car, so I ordered a zoom clutch from summit for a 64 Chevelle, also my clutch master rod had snapped when the old clutch was in it, so I ordered a willwood 3/4" bore pedal and clutch master, and I ordered a stock gm hydraulic slave, the old one had a small leak on it. So new pedal, master, slave and clutch and now system will not work, any ideas?
     
    chryslerfan55 likes this.
  2. saltflats
    Joined: Aug 14, 2007
    Posts: 9,659

    saltflats
    Member
    from Missouri

    A little more info may help as in what it is not doing.
    Does the system still have air in it?
     
  3. I don't understand what's not working. Is the pedal going to the floor? Is the clutch not engaging at all?
     
  4. Camron.est1991
    Joined: May 28, 2017
    Posts: 19

    Camron.est1991

    Clutch is not engaging at all and system is fully bled, the slave seems to have plenty of travel, it pushes the fork a good 1"-1 1/2"
     
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  5. Camron.est1991
    Joined: May 28, 2017
    Posts: 19

    Camron.est1991

    I know the originally in a 64-65 chevy with a m21 had mechanical clutch linkage but my grandpa had it working with the hydraulic slave and master, but some how now that all parts are new the clutch won't engage
     
  6. seb fontana
    Joined: Sep 1, 2005
    Posts: 6,006

    seb fontana
    Member
    from ct

    You may need a longer throw out bearing retainer if you went from a borg&beck three finger pressure plate to a diafram type pressure plate..Diafram uses a long one while the three finger is short..At least used to be..
     
    Atwater Mike likes this.
  7. Camron.est1991
    Joined: May 28, 2017
    Posts: 19

    Camron.est1991

    See I found that m21's come with these three types of throw out bearings. I have the shortest one. That's what was in it originally when the system worked, the new clutch came with the same one(brand new metal one), you think I need the longest one or mid?
     

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  8. Camron.est1991
    Joined: May 28, 2017
    Posts: 19

    Camron.est1991

    And what's three finger or diafram pressure plates? I know the original that worked had more then three fingers, and so does the new one, the only difference in the old and new is the fingers stick out more then on the old one because the fingers on the old one were wore out I assumed, and the fingers sticking out more would give me more throw I would assume. O and the old one had an asbestos friction plate where as I have an organic now, maybe it has something to do with those cancerous qualities of the asbestos one haha
     
  9. saltflats
    Joined: Aug 14, 2007
    Posts: 9,659

    saltflats
    Member
    from Missouri

    So what you mean is the clutch will not disengage?
     
  10. Camron.est1991
    Joined: May 28, 2017
    Posts: 19

    Camron.est1991

    Well ya haha sorry, when it's in gear and I push the clutch it stays in gear
     
  11. saltflats
    Joined: Aug 14, 2007
    Posts: 9,659

    saltflats
    Member
    from Missouri

    Clutch disc in backwards?
     
  12. Camron.est1991
    Joined: May 28, 2017
    Posts: 19

    Camron.est1991

    No it says on it"this side to flywheel"
     
  13. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 1,796

    2OLD2FAST
    Member
    from illinois

    There are 3 different style of pressure plates ; B&B [3-finger] , flat finger diaphram , raised finger diaphram , there are 3 different heights of throw out bearings & 2 different height clutch pivot balls as well as numerous different release arms....not knowing what you have makes it impossible to ediagnos your problem...
     
    BigPerm365 likes this.
  14. Camron.est1991
    Joined: May 28, 2017
    Posts: 19

    Camron.est1991

    That's the clutch I have for it, I have the short throw out bearing part# cc1705c as for the pivot ball for the fork idk
     

    Attached Files:

  15. seb fontana
    Joined: Sep 1, 2005
    Posts: 6,006

    seb fontana
    Member
    from ct

    right now how much clearence is there between the throw out brging and the PP fingers with the brging against the the trans with slave cyl disconnected?
     
  16. Camron.est1991
    Joined: May 28, 2017
    Posts: 19

    Camron.est1991

    1/8" air gap, is that what you mean?
     
  17. saltflats
    Joined: Aug 14, 2007
    Posts: 9,659

    saltflats
    Member
    from Missouri

    Are your piston bores the same as what it had and are you in the same pivot point on your pedal?
     
  18. 1961 Poncho
    Joined: Feb 19, 2017
    Posts: 134

    1961 Poncho
    Member
    from Las Vegas

    You pivot ball adjustment might be your problem. Make sure you have the right size and length.
    Get tech support from zoom on this. This is their bag. Good luck!
     
  19. Camron.est1991
    Joined: May 28, 2017
    Posts: 19

    Camron.est1991

    All the same but the pedal I moved it up a little so it would clear the floor better to get more throw from it, and I'll try and call them tomorrow good idea
     
  20. 1961 Poncho
    Joined: Feb 19, 2017
    Posts: 134

    1961 Poncho
    Member
    from Las Vegas

    The pivot is about the fulcrum and leverage on the fork which is directly portioned to the throw on the throw out bearing. Make sure you have the right one. They are a cheap fix.
     
  21. 1961 Poncho
    Joined: Feb 19, 2017
    Posts: 134

    1961 Poncho
    Member
    from Las Vegas

    Fixed yet? What was the solution?
     
  22. Camron.est1991
    Joined: May 28, 2017
    Posts: 19

    Camron.est1991

    No not yet haha what do you think about pressure plate spacers?
     
  23. rjones35
    Joined: May 12, 2008
    Posts: 865

    rjones35
    Member

    I have a different set up than you, but with my hydraulic slave it took a lot of bleeding before it would finally work right. Are you sure it's totally bled?
     
  24. I have almost the exact same set up in my Ford, used a Speedway push slave with a 7/8" bore. Master is the same as yours and I have good pedal travel, the clutch works nicely. Must be a pivot issue, how easy is the pedal to actuate? Mine is fairly easy.
     
  25. Camron.est1991
    Joined: May 28, 2017
    Posts: 19

    Camron.est1991

    Mine is fairly easy too but you can see the throw out bearing pushing on the diafram fingers like crazy if you look in the side of the tranny where the fork comes out, which a buddy of mine said he has seen spacers for the pressure plate(they look like little washers) and that might fix it. I have tried every bleeding method I can think of.
     
  26. The shop I worked in for 26 years had a clutch rebuilding dept. at one point, and I learned from observations and later info that made sense on how they would adjust the finger height on truck clutches to spec. This applies just as much here as it does for a medium/heavy duty truck application.
    When clutch pressure plate are built, finger type or diaphragm type, the builder wants the finger height to be at spec installed on the flywheel with the known disc thickness per clutch application, not custom.
    If you shim away the pressure plate you have, the fingers will descend at what ever ratio is correct, and you lose plate load, i.e grab on the disc, and height for the release bearing to make this work.
    I would say you have the wrong pressure plate/disc application for what you're working on. Or something else has cause a need of adjustment of it, not the clutch assembly.
     
  27. Camron.est1991
    Joined: May 28, 2017
    Posts: 19

    Camron.est1991

    Well my clutch is engaged no matter what so wouldn't spacing the pressure plate a little just loosen it up enough to release the friction plate? What do you think then? Pivot ball?
     
  28. Please do not space away the pressure plate. The result of that is like I described in another post.
    You lose plate load, less grab on the disc, and the fingers dropping at the spring ratio of the plate designing.
    The pivot ball height going away from the transmission face will change the fork's forward application of the throwout bearing.
    I remember something about Chevy car manual transmissions having more than one input shaft retainer length, corresponding with finger height, and correct contact for the throwout bearing.
    I could tell you more about big truck, same rules.
    One more tech tidbit. If you don't resurface your flywheel, you have less spring pressure on the disc, increased wear, and NO WARRANTY for parts installed afterwards.
    Many guys here can help more in the morning. Paging SEG clutch racers! Thanks.
     
  29. Was working before disassembly? What part # stamping info?
     
  30. What was the clutch part number from Summit? I may have the same one in my car if its 11". The TO bearing was short, not sure if it was the shortest. What bellhousing are you using? I'm using a cast iron one out of a '55 Chevy with a forged steel truck fork.
     

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