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Repair of Broken pressure plate.

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  • Repair of Broken pressure plate.

    I am SOOOOOOOOOOOOOO mad I can't see straight.

    I broke the second pressure plate on the clutch. The one with the six bolt posts that protrude through the clutch plates. It broke one of the post. Long story but I was tightening the 27mm nut that requires 51 ft-lbs of torque!

    Question is:

    Will JB weld hold the "bolt post"? They say that epoxy is good for 1500 psi. The pressure plate is made of aluminum so it doesn't require a lot of "strength" anyway.

  • #2
    Agreed

    Agreed.

    So this is what I did:

    Here's what it looked like after it broke. The post snapped clean at the base. The two pieces fit back together perfectly.

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    I noticed the post had a hole al the way through it. There was nothing on the back of the plate where it fits against the clutch basket to prevent inserting a stud...and the hole in the post can't be for transfer of lubricant since the pressure plate bolts fill the post hole.

    I put it in vice to hold the broken pieces in place while I tapped it with a 6mmx1.0 tap.

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    I tapped about 1/4 inch into the break. Then I cut a headless stud from a 6mm bolt and slotted the end with a hack saw so I could screw it into the newly tapped base of the post. The stud was cut to the exact length as the threaded hole so it would only screw in so far then stop. That way the bolt could go no farther and be "locked" into place.

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    Next I coated the stud in Lock-tite and screwed it into the base of the plate post (as snug as possible) until it bottomed out into the tapped hole.

    Click image for larger version

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    Then on the entry end of the hole I filled it with JB Weld to prevent the newly seated stud from backing out of the hole.

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    To finish it I ground the excess JB Weld down with a dremel.

    I've pulled on the post pretty hard with a bolt in the end and I can't see where it could fail any easier than the original piece. As a matter of fact it appears to have MORE support than the original piece.

    Please critique. This is a learning process for all. These bikes are getting harder and harder to find parts for. I talk to the Yamaha dealer and they can get this part but it will be shipped from JAPAN! There aren't any in the US...so they had no idea as to when it would arrive.

    L8R

    Cody
    Last edited by tplank; 11-15-2020, 02:35 PM.

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    • #3
      Yes, great job!!!! I remember seeing a complete clutch basket set on Ebay yesterday, but I think your fix will work well. Was just wondering if you might have put a bit of J-B Weld around the fracture for further support! Did you use STUD grade RED locktite?...BTW, I saw a PROFESSIONAL grade in the auto store the other day!!

      Note to self....save link for making tech tip for repair section!!
      T.C.
      T. C. Gresham
      81SH "Godzilla" . . .1179cc super-rat.
      79SF "The Teacher" . . .basket case!
      History shows again and again,
      How nature points out the folly of men!

      Comment


      • #4
        Yep...red locktite. I saw the "pro" grade too about a month agao when I was in NAPA. I think the guy told me that stuff is a total bee-otch to get loose if you need to. Of course in this case I would never want it to turn loose.

        I did put a little JB around the fracture but I couldn't get it very thick because of the clearance around the holes the posts go through. I just put it together and it seems ok. We'll see. I went ahead and ordered one from Yammy. But have no idea when It'll get here since it's coming from Japan.

        BTW TC, I mailed your parts today. You should get them by Friday or Saturday. Let me hear...ya hear?

        Comment


        • #5
          I wonder if threading and studding all the posts when replacing the clutch would strengthen this weak spot on our drive trains? Might prevent accidental breakage on reassembly.
          Also, doing this to all would keep this spinning part balanced. A couple of ounces off @ 8,500 RPM might cause a vibration or harmonic.
          Just thinking out loud here.....
          Pat Kelly
          <p-lkelly@sbcglobal.net>

          1978 XS1100E (The Force)
          1980 XS1100LG (The Dark Side)
          2007 Dodge Ram 2500 quad-cab long-bed (Wifes ride)
          1999 Suburban (The Ship)
          1994 Dodge Spirit (Son #1)
          1968 F100 (Valentine)

          "No one is totally useless. They can always be used as a bad example"

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          • #6
            balance

            That's an interesting thought, Pat. I don't know if I'd do it to all of them,, but just the post opposite the repair to balance it out.

            and Maximan... fantastic repair! One is never as creative as when his back is against the wall. (or when money and time is involved)
            "Damn it Jim, I'm a doctor, not a mechanic!' ('Bones' McCoy)

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            • #7
              Well, I just had to go out to my shed and look at my spare clutch to get a better idea of just what you've done with this repair. All I can say is WELL DONE! Better get a Paypal account set up so folks can send you their broken pieces for the genuine Maximan fix....
              Ken Talbot

              Comment


              • #8
                Originally posted by Pat Kelly
                Also, doing this to all would keep this spinning part balanced. A couple of ounces off @ 8,500 RPM might cause a vibration or harmonic.
                Just thinking out loud here.....
                OH GREAT! Thanks a lot Pat...now I won't sleep a wink tonight!

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