Help with plastic crank arm bolt

Nerubian
Nerubian Posts: 11
edited September 2014 in Workshop
I got a Dahon Mu SL folder a month ago and up until today it's been running like a dream. Then the cranks started creaking horrendously and inspection revealed a loose left crank arm bolt to be the likely culprit.
I had not really looked at it until now and saw it was plastic with extra impressions around the key hole but I just straight whipped out the bike tool and tried to tighten it on the spot - and immediately semi threaded the damn thing.

Doing what I should of done first and looking in the bag of bits that came with the bike there is a plastic tool to fit the keyhole and impressions but alas the damage is done and I am unable to tighten or even loosen it now. The arms that fit the impressions seem to offer a trivial amount of extra torque over the key hole due to little depth anyway.

What to do now?, the cranks are still creaking although not as bad as before.

C0edX2N.jpg

Comments

  • nicklouse
    nicklouse Posts: 50,675
    See the pinch bolts either side of the arm? You will never move the preload adjuster with them done up.

    (Just like an Aheadset).

    Undo the pinch bolts a little by little each side then adjust the preload. Then tighten the pinch bolts.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Nerubian
    Nerubian Posts: 11
    Thanks Nick
  • keef66
    keef66 Posts: 13,123
    With the pinch bolts undone you should be able to tighten the preload cap a bit and pull the non drive side crank onto the spindle. It's made of plastic because it's only supposed to be done up finger tight; just enough to preload the bearings. Make sure you tighten the pinch bolts sufficiently. Alternate between them until they are both fully tight.

Categories