Pinch bolt side-play?

Discussion in 'General Amphicar Discussion' started by Jon March, Nov 3, 2018.

  1. Jon March
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    Jon March Member

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    We all know that there is "pulling pressure" exerted on the side of the pinch bolts by the "contact point" of the u-shaped groove that is machined in the swing-axle ends.
    And if you dont temporarily "relieve" that tension with the proper tool Gord sells, this is what happens when you remove or replace them! ... "groovy"

    Screen shot 2018-11-03 at 12.54.02 AM.png


    But here is my real question: >>> is there supposed to be THIS much play?
    I would think with a safety item like this that it should be a slightly tighter fit (>> maybe a "fatter" diameter pinch bolt??
    (The one shown is a grade 12 that i was going to use, but ended up using new grade 10 OEM bolts from Gordon Imports -

    ....but regardless - they both seemed to be the same diameter and have the same looseness in that crucial (and tiny!) contact area. I would think the fit should be a bit higher tolerance - would hate to have the axle work past a too-narrow bolt and slip off the nut broke, etc.

    This "play" in these could cause a person to make a mistake in the 1/3rd-turn backnut tightening step - if a person didnt remember to push the stub axle in until the groove hit the side of the pinchbolt





    This is my pinch bolt procedure - add any corrections:

    pre fill tube with grease and grease brass bushing before fully inserting axle
    grease outer washers against brass
    DE-GREASE squeaky-clean the polished axle end and inside of oscillating swing arm hole
    put oscill swing arm on


    insert fresh pinch bolt and screw nut at bottom barely loose for now...

    >> NOW: DONT FORGET - put any needed "brakeline brackets" under the head of (new) pinch bolts

    Push swing arm tight against buffer disc on flange & brass bushing

    push in on stub axle until it contacts the side of the pinch bolt to take up "play"

    add fresh Belvedere cupped washers (if desired/needed)
    tighten inner large back-nut so that both cupped washers are JUST moveable
    THEN: turn inner nut 1/3rd to 1/2 turn - but don't crush them completely

    (this SHOULD translate to 3 o'clock rigid-drag friction)

    finally tighten & torque pinch bolt nut to 75 lb? & secure with stainless steel cotter pin
     
    #1 Jon March, Nov 3, 2018
    Last edited: Nov 4, 2018
  2. Jon March
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    Jon March Member

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  3. fouramphs
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    fouramphs Member

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    Jon I have that Prop here in Fl. Email me....
     
  4. Jon March
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    Jon March Member

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    Gord- i was able to find one actually. Maybe i will swing by in March and do sum shoppin!
     
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