Hilti DX 351-BT Manual page 33

8.5 Additional checks in the course of the tool service
WARNING
Risk of injury! A faulty piston brake, piston or fastener guide leads to an increased risk of malfunctions.
▶ Check the piston brake and piston for wear and replace them if damaged.
▶ Do not tamper with or modify the piston.
▶ Do not attempt to repair a faulty piston yourself, for example by grinding the tip.
1. Replace the piston if you establish that any one of the following points applies:
▶ The piston is broken.
▶ The piston is badly worn or chipped (e.g. a segment of more than 90° of the circumferential
ring-shaped elevation at the piston tip broken away)
▶ The piston is bent (check by rolling the piston on a smooth, flat surface).
2. Replace the fastener guide if you establish that any one of the following points applies to the piston
brake:
▶ The metal ring of the piston brake is broken or detached.
▶ The piston brake no longer holds on the fastener guide.
▶ Piston jams in piston brake.
3. Replace the paint guard if you establish that any one of the following points applies to the paint guard:
▶ The paint guard shows signs of wear.
▶ The paint guard shows visible damage, for example cracks, chipping.
▶ The paint guard is missing.
8.6 Final check of the fastening tool
▶ After carrying out care and maintenance, check that all protective and safety devices are fitted and that
they function faultlessly.
9 Troubleshooting
9.1 Problems with the fastening tool
Before you start troubleshooting, make sure there are no cartridges and no fasteners in the fastening
tool. If the cartridges cannot be removed, contact Hilti Service.
If the trouble you are experiencing is not listed in this table or you are unable to rectify the problem by
yourself, please contact Hilti Service.
Trouble or fault
Higher force required to press
the tool against the surface
Triggering resistance
increases
Adjusting knob for driving
energy is difficult to turn
Fastening tool cannot be fired Fastening tool was not pressed
The piston jams in the fas-
tener guide
*377627*
Possible cause
Build-up of combustion residues.
Build-up of combustion residues.
Build-up of combustion residues.
fully against the working surface.
Piston incorrectly installed.
Fastening tool is faulty.
Fastener guide not correctly
screwed on.
Piston bounce because driving
energy is too high.
Piston and/or piston brake dam-
aged.
377627
Action to be taken
▶ Service the tool.
▶ Insert new cartridge strip.
▶ Service the tool. → page 26
▶ Contact Hilti Service.
▶ Service the tool. → page 26
▶ Press the fastening tool fully
against the working surface.
▶ Check installation and, if nec-
essary, repeat the installation
procedure. → page 22
▶ Contact Hilti Service.
▶ Turn the fastener guide until it
engages with an audible click.
→ page 22.
▶ Reduce driving energy.
▶ Check piston brake and piston
for wear; replace the compo-
nents as necessary. → page 27
English 27