Rebuilding a Bosch 11316EVS Demolition hammer

Everything is straightforward except replacing the balls in the chuck, so I left the chick with a local rental place to do that.

-Tools required:

Phillips screwdriver
Allen wrench set
10 mm hex socket drive
Torque wrench
Soft wire (found in hardware store near picture framing stuff)
Needle nose pliers
Larger flat blade screwdriver (1/4” tip)
Small screwdriver and/or dental probe (remove O rings)
VSR drill
Small drill bit
Internal snap ring pliers (chuck)
Drift (chuck)
Very small sheet metal screws (chuck)

- Personal protective equipment

Paper towels
Vinyl gloves
Safety glasses

Remember to inspect and clean parts.

You can take off screws #27 and set aside the chuck
You can remove #41 through #29 on the exploded parts diagram
#35, the guide tube, you can remove a little later when you can position the piston, #56.

The power switch cover, #77, the shift plate, must be removed and installed in the off position. You must pry the cover from the bottom.

Remove 2 x #136 screws and 4 x #140 screws. The former are machine screws.

Now is a good time to do the brushes one at a time.
Remove the Faston clip on the brush,
Use a pair of needle nose pliers and lift the brush spring. Place the soft wire under the brush spring. Use it to lift the brush clip and insert the new brush. Attach the Faston terminal connector.

Remove 4 x #127 screws (Impact housing assembly)

Remove 4 X 125 screws. (motor housing)

Remove #115 with a 10 mm hex wrench.

Remove 4 x #129 screws and remove the impact housing assembly.


Observe the piston and move the motor at the base such that the connecting rod is at the back of the drill. This will make it easier to remove item #35, the guide tube. Remove item #35. Once #35 is removed, you can remove the piston. I forget if it needs to be positioned far forward or far back.

The Eccentric Gear, #72, will drop out.

Now it’s basically simple to clean up all the parts, reassemble and regrease. Don’t forget to grease the O-rings prior to assembly.

Everything is straightforward EXCEPT the connecting rod, #70, and especially #35, the inner piston cylinder (guide tube).

Once #72 is back in place and the stub positioned to either the (front or rear?) of the hammer, the piston can be inserted and the connecting rod attached. The guide tube must not be in place when connecting the piston.

The piston must be totally retracted in order to put back #35. It’s much easier to do in this position.

The switch plate #77 and #112, threaded ring, are other potential issues.

#112 has a notch and only assembles one way. The torque specs are located in the rebuild kit. I wouldn’t torque this until everything is assembled.

Insert the switch at an angle from the top with the switch underneath in the OFF position.

Now, you basically have everything assembled up to #41 looking at the exploded view, the upper housing minus item #41.

I then inserted two of the #27 screws and placed a piece of soft wire to hold everything in place and set it aside.

Now, it’s time to deal with the chuck. The dust shield, #21 is surprisingly easy to remove. Insert a screwdriver in the middle and pry. I learned that later.

#18 can be removed with snap ring pliers. Remove the spring around the seal and cut the seal to see what your doing. What you want to do is drill a hole at an angle into the seal. The hole should be just big enough to start the sheet metal screw. It’s nearly impossible to drill the hardened housing. The holes should be 180 degrees apart. When you insert the screw the seal will unseat.

#138, “O” ring can be removed with a small screwdriver. Incidently, this is a -124 O-ring (Dash 124). Viton would be a better material, but Buna-N shoud be fine. The rental company lost it on me so I had to find a local replacement.

As I said the tough part seems to be removing #143, the spring ring. I punted.
It does seem that you need to compress #31, bushing, by item #144 washer.

It seems to take a bit of force to compress the bushing and I didn’t feel like trying to build a press. After paying $30 for someone else to just do the balls, I was told that a press is not needed.

Remember to torque #112, the threaded ring.

No bearing replacements were done.



It's odd that the grease p/n is not on the parts diagram and the dust cap is not available separately and it's not even shown on the diagram. The diagram that comes with the rebuild kit also contains a little bit more information.

It was somewhat difficult to figure out the Vario-lock feature of the chuck.
And who knows why there are so many types from hex, spline, sds, sds max and sds+