Makita HR3000C lost hammer action suddenly

[mybabybook]

hi all,

i have a makita HR3000C which I used quite often in the last month. Yesterday, I was using it mainly on hammer only. I noticed at some time that it hammers slower and not as powerful as it should even being on 5. Then I used it on hammer and drill, and it suddenly lost hammer action. It drills, but no hammer. On hammer only, the motor spins no problem, no funny sounds, just no hammering. Strange thing is that when I put the tip of the bit upwards, i can get hammer action. Maybe not as powerful and fast as it should, but it is there. As soon as i hold the tool horizontally or point the bit downwards, it disappears. When can the problem be?

[Eric - TIA]

That seems to happen with a lot of hammer drills.  Not sure how old it was but one of the product managers at a company once told me that a hammer drill is really designed for light applications but users try to use them all the time and it wears them out quickly.  Not sure how old your is but it sounds more like a hammering issue than an electronic issue.  Just not sure how to fix it.

[mybabybook]

So far, I changed o-rings on striker 32 - Makita STRIKER HR3000C and piston 46 - Makita PISTON HR3000C. No change. Today after disassempling further, i found the 29 - Makita WASHER 19 HR3000C had a broken part, the neck cracked in half, with one half completely came off. Also, 27 - Makita RUBBER RING 13 HR3000C seems worn out on the inside. Can any of those be the reason for no hammer action? 

[Gun]

I have the same issue. 

The speed also goes up and down without touching the dial. Hope it's a quick fix. I do use it a lot on hammer and hammer drill. I hope there is a quick fix