ACR J10 Bevel Gear Wear

I have some bevel gear wear on my ACR and im wondering if i need to change the motor height?
Or what else could i do to stop this.
Also, would it be necessary to replace the bevel gear if it is in this condition?

Thanks in advance!!!

The mesh is loose, you need to set the pinion height and shim the bevel to pinion mesh


By the looks of that it wasn’t far from going Bzzzzzzzzzzzzzz…:astonished: was it noisey when firing?
I think you should notice a bit of a different sound once it’s all set up right.

Yep, it was happened to the nylon gears, and i could hear it slowly happening again…
Glad i checked!! :sweat_smile:

I personally would consider that bevel and the pinion gear as destroyed and would not use them now :frowning:


Ok, but weirdly enough the pinion gear looks fine!!!

It may look fine but it will be worn and shaped from the poor mesh that was set.
If you replace the bevel you should allways replace the pinion


I agree, they’re shagged!! I meant that set would have made a sort of grinding noise from the outset. And a new set of gears fitted and shimmed correctly and lubricated should sound completely different to what that did.
It almost looks like the pinion gear is sitting too low on the shaft! I know with my acr the gear sits slightly higher. Be sure to use loctite on the grub screw.


Ok, thanks, would it be worth getting a adjustable base??

It’s not necessary because once the pinion is at the correct height you never need to adjust it , you just shift the position of the pinion on the shaft and use 609 loctite to secure it and blue loctite on the screw.


Ok, after looking at it a bit closer, as @daveb said the problem seems to be that the pinion gear is to far onto the shaft, but i cant seem to get it off!!! I had to use a hammer to jam it on, soooo… :thinking:
Anyway, ive looked at the motor, and i figured if i could hold it deeper into the receiver it should fix the problem.
As i cant move the pinion gear would an adjustable base work?

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You can get an adjustable base or shim the existing one to push the motor further in.
As the motor is spring loaded, you can push it in by hand to get an idea of how far in it needs to be, then back off a bit.
The wear on bevel gear instead of pinion simply indicates one being harder.
Change the bevel gear if you like. From your pic, there is plenty of untouched contact area on it and there is plenty of use left provided you mesh it properly.

Last but not least,
motors and hammers do not go together. If you need to use that much force, you should consider filing/grinding a little off the flat section of the shaft.

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Sorry but no do not do that !
Adjusting the motor deeper with the base plate will move the motor to a position where the base plate no longer captures it correctly and will let the motor rotate in the grip.
A worn bevel and pinion is US, if you use it you are a butcher !

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