Question about Hitachi Hammering

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Hitachi H85 I rebuilt the Bottom end of my Hammer,New piston,L-ring and other rings that where pertinent to the unit. The hammer now works but has no real breaking power.Do I need to break it in ?

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Try just stopping and starting the machine off a see if the hammer appears.

Posted on May 03, 2014


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Posted on Jan 02, 2017


Jim Goldsmith

  • 2005 Answers

SOURCE: Need manual for Hitachi Demolition Hammer

Posted on May 28, 2009

John Trevino

  • 1420 Answers

SOURCE: Hi.I have a Hitachi H45MR.

Your hammer uses an air cushion created by drive piston to move a driven piston which contacts a second piston or striker. The second piston or striker is the part that contacts the bit. The striker can become restricted from moving to its full limits by debris or just worn slightly shorter (the part of the bit that enters the gun can wear shorter also ). Lack of movement due to debris or shorter length due to wear will cause weak hammering action. Assuming the bits are not worn where they enter the gun, as you push the bit all the way in into the chuck, the bit moves/pushes the striker into position close to the driven piston. The driven piston receives its power/movement from good vacuum between the driver piston. Good vacuum is created when there is good contact with orings to cylinder and good clean lubrication (Use Hitachi gear/hammer grease). As the grease heats up, it will run out of the cylinder. Good clean grease will remain in cylinder even after heavy use. Dirty grease and loose orings will loose power/vacuum to driven piston. You stated that you have different hammering action depending on position indicating that pistons are loose in their cylinder. The hammer should be stored with the nose pointing downward after use so that the driven piston will stay at the end of the cylinder and not slide against the driver piston (when the grease is hot, the driven piston can slide against the driver piston and will take longer to begin hammering).

Posted on Sep 21, 2011

Repair Ahjoshe

  • 885 Answers

SOURCE: complet break down of makitia demo hammer

Go to, put your model number in the search box and hit the arrow or enter. Select your tool and the parts breakdown and owners manual will be available to view or download. The owner's manual has their recommended lubrication requirements.

Posted on Dec 29, 2011

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1 Answer

How to disassemble a Bosch 11241 hammer drill.

This is a pretty complex tool to tear down, make sure you're up for it.
1) you need to remove the bit holder assembly (#21-30) by prying the rubber seal off on the end, sliding the sleeve off, removing the hog ring, and then the 2 pawls along with the remainder of the bit holder parts.
2) In the nose of the tool behind the bit holder is a large snap ring (#154) that must be removed.
3) Remove the screws on the gearcase cover on the top (#873) and remove the cover.
4) The entire barrel assembly will slide out of the nose (This is generally not easy)
5) Using an o-ring pick or small screwdriver through the holes on the side of the barrel you can reach another hog ring on the inside - once released you can push the striker and hammer out from the nose out toward the piston end.

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My hr5201c rotary hammer does not hammer even after replacing the piston rings. I notice that when I depress the trigger it hammers. What could be the problem?

How is the health of position 21 until 27 ??? i think the impactbolt pos 24 has a problem because of the weakness of the material thats used by most of the rotary hammers in these days ,a rotary hammer is not specially made for longlasting jobs, only a few brands have had it like DUSS and Hilti but a demolition hammer is made by more expensive heavier quality materials and made for working 1 or max 2 hours at a strech , a rotary hammer cannot last that jobs.
Buy a consumables kit for this machine, and the special grease for it and use only the Makita heat-resistant lubricant, because only replacing piston rings will not work beware on the lubrication when if there was something leaking in front the o-rings are all be hard and weak because when the pneumatic function is lost and its leaking in the front of the spindle is the first thing to have an good working(and not leaking) inpactbold is the highest priority for the function of the hammerfunction. the first link is having the list

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Get a large wood piece like a 2x2 and put one end on the piston head and the other end you smack with a hammer. Drive the piston out through the bottom in case there is a carbon ring build up at the top of the cylinder.

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How to put oil in Hitachi H65

OIL ?? I think Hitachi has always a yellow grease lubrication
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Otherwise BOSCH HILTI and the one and only brand DUSS demolition hammers and also a few brands of Chinese hammers need oil lubrication . an expensive sinc-free hydraulic oil the same as used in some pressure washers life lasting oil but for HItachi look at the link for the grease 2 tubes a enough . good luck and dont forget the piston pin to replace with a new not only the gaskets and o-rings and also the oil and dirt seals on the front where the striking pin is that must be absolutely not air leaking because all your work burns in a few months again out . you can start all-over again.

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1 Answer

Hr 3000

Frequently the problem for this is a plastic ring that has three pins in it. Normally the pins break through the bottom of the ring.
You need to take covers off. Strip SDS chuck. Remove plastic cap from end of drill then remove large internal retaining ring. Tap end of drill with mallet and eventually the tool holder will come out.
At the bottom of the tool holder there is a thin O ring (all this does is keeps a plastic gear and springs on the tool holder.) Remove this ring gear and springs can now be removed. You should now see the plastic ring (approx. 30mm long) Examine ring and pins, probably need to replace ring. This is usually the cause of not hammering, I have found changing seals works for weak hammering. Although having stripped the drill to this point I normally change the O rings on the hammer and piston. Rebuild is reverse of stripping be careful with the thin O ring not to snap it.

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2 Answers

Ring holding fuel pump in tank is corroded / rusty. Can't move it, are the tabs secured with slots OR by turning the ring will the slots move and tabs stay put??

I remove them with a flat punch and a ball pean hammer gently tap on the ring away from the stops and the ring will rotate off

May 12, 2011 | 2001 GMC Jimmy

1 Answer

Hilti TE 17. Hammer doesnt work. Rotary does.

Most likely the O-rings are worn - tool has no compression to move the hammers inside.
Less likely: the connecting rod for the piston is broken so piston isn't moving - or 2nd hammer is broken into pieces.
I would open it up & check the orings first

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1 Answer

The hammer will not return to neutral after firing. Porter Cable with little use but purchased several years ago.

I removed the head of the nailer and then pulled the hammer out of the cylinder. I removed the o ring and carefully cleaned each part of all particles and blew the cylinder out with an air hose. I placed a couple drops of the proper oil on the slot for the o ring and a couple drops in the cylinder and reinstalled the piston/hammer being sure to match the hammer grooves into the guide/nail slide. I replaced the large o ring in the head mechanism after carefully cleaning and oiling as above. After reassembling, the nailer worked like new.

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1 Answer

Metabo model 6030 will not hammer help out

There are several possibilities. Remove the cover from top of gearbox. The piston / sleeve assembly will be visible. Wiggle the assembly to check for side play. If the assembly is loose side-to-side, loosen one of the support tracks (two allen screws). Wedge a screwdriver between the track and the housing and then re-tighten the screws. Another possibility is that the piston o-ring is worn. stand the tool on its nose, if the piston falls quickly forward, the o-ring is worn out. This part is no longer available. If the piston does not move forward, smack the nose firmly against the work bench. If it still does not move, the piston lube may have dried out. Shoot some WD40 into the sleeve for a quick test. Another possibility is end wear of all hammering parts in the tool. This can be difficult to determine if you dont know what they looked like originally.

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1 Answer

Seems it doesn't hammer hard enough. Looking for diagram and a place to get parts. Thanks

piston inside tube has a o-ring on it, these wear over time.. take apart replace piston o ring. Make sure to clean out all grease from inner tube and regrease all these parts when putting back together. should hammer better.

May 06, 2009 | Drills

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