Question about Makita Tools 18V 1/2" Lxt Lithium - Ion Hammer Driver - Drill Kit - BHP451

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Have taken apart the makita bhp 451 hammer drill to try & repair but not sure where the 2 small pins go in the gear assembly. Any ideas or would you have a diagram of the gear assembly? Thanks!!

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The two "rollers" Rodino is talking about fit into the recess in the middle of the clutch/chuck housing. If you look there is a piece similar in shape to a wing nut that rotates to drive the chuck. The top and bottom of this "wing nut" are flat. The "rollers" fit loosely in the recess next to these flat sections.You'll know if they're in the right position as without them you can turn the gears with the chuck. With them in, they bind and allow you to tighten and release the chuck without the gears turning. Took a lot of experimenting to find this out.Good luck!!

Posted on Feb 02, 2013

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If you are referring to 'pins' (about 10mm x .8mm) then these are stop pins. They sit into the clutch/chuck housing. If you look at the array of sprung pegs protruding from inside the clutch/chuck housing, you will see two small holes, diametrically opposite each other and very close to the sprung pegs. Those pins fit into each of those holes.

I hope this helps. If you are talking instead about two little rollers (about 8mm x 3mm) then i too would like to know where they go!


Posted on Sep 05, 2010

  • Phil Steward Oct 21, 2012

    Did you find out where they go?



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