Crank Arm

[JJDT]

Bought a set MTB pedals for my son's MTB to replace those standard plastic pedals. Removed the pedals a while ago, did not pay attention to any damage as the pedals screwed out fine. This weekend when I tried to fit the MTB pedals saw that the left side thread on the arm is somewhat stripped. It is only the first coil as the pedal screw on and just as it is going on the first full turn it jumps out. The rest of the thread is fine no damage. Is there a tool available just to clear the thread or must I go out and buy a complete new crank arm.

[Johan Bornman]

There is a tool available. It is an expensive tool that's not typically a DIY tool. It is a right/left hand tap and special insert sleeves. Once the crank is stripped, there's not enough meat in there for a chasing only and it thus has to have a new sleeve fitted.

[Showtime]

There is a tool available. It is an expensive tool that's not typically a DIY tool. It is a right/left hand tap and special insert sleeves. Once the crank is stripped, there's not enough meat in there for a chasing only and it thus has to have a new sleeve fitted.

But is seems as though he has enough good thread left, it's just the entry portion of the thread that's damaged. So it shouldn't need to be sleeved?

[Captain Fastbastard Mayhem]

as a hack job, and to avoid buying the tool that JB has suggested, try inserting the pedal from the other side of the crank and screw it all the way in. That may enable the thread to be reformed. As it's only the initial mm or so, it should be alright, as long as it's ONLY that section that's miffed.

 

Also - afaik the left side thread is the "normal" one - if the pedal's thread is slightly too short, then you can try to source a bolt that is the same size as the pedal's thread, but just a bit longer. Then do what I said above...

[ThePubSA]

Sometimes you can retrace the stripped part of the thread with a sharp nail or w.e will fit into the groove.As you trace the thread, you get a corkscrew bit a steel coming out that filled the thread,sometimes thats all it is if its not totally stripped flat.

ID try mayhems option before mine & w.e you can before buying new

[JJDT]

Thanks for the replies forgot to add it is the left side. As for the pedal from the rear it is a tad too short, to find a "left treaded" bolt with the same thread pattern is a bit of a mission. As for the re-sleeving it is just the firt coil as to speak that is damaged the rest is fine, so I will not go this route. Maybe the last option is to buy another set of these plastic pedals butcher the pedal in order to work as a bolt and work it through from the rear of the crank.

[Dustbin Dog]

Make your own tool to chase the thread. Ask your LBS if they have a scrap pedal with a hex drive in the center. Strip the pedal parts from the axel and cut the thread off in front of the shoulder. Screw the threaded section into the opposite end of the crank and drive using a hex allen key. This should chase the damaged threads.