DeWalt PA3500 Mode D'emploi page 14

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PA3500
REPLACING OR REPAIRING THE PISTON
The piston is an expendable part and must be replaced periodically. Typical signs of a
worn out piston are: breaking, bending or mushrooming.
Prior to servicing the tool make sure there is no powder load in the tool. Use caution
and do not lose or damage any tool parts.
1. Using a pin, lift the end of the annular ball spring and rotate toward the top of the
tool body. Pull the piston stop back and out of the tool.
2. Slide the piston guide and baseplate assembly out of the tool.
3. Using a fastener, pry the shear clip off the baseplate. Replace the shear clip if it is
damaged.
4. Remove the baseplate from the piston guide, then pull the piston out of the guide.
REASSEMBLY:
5. Tilt the baseplate and slide the fastener guide out. Press the guide out of the
baseplate using a piston if it does not slide out freely. Replace the guide if it is
damaged.
6. Clean the piston using a wire brush. Inspect it for worn or damaged piston ring,
chipped end, or bending. Apply lubricant to the piston shank to minimize piston
sticking from an overdrive con dition. Wipe the piston dry.
7. If a piston tip is damaged, it can be shortened a maximum of 0.20 inches (5mm).
The tip of the piston should be ground flat and at 90 degrees to the shank of the
piston. The cham fer of the piston must also be reground as shown. Piston grinding
should be performed by qualified per sonnel using the proper equipment.
8. Press the piston into the end of the piston guide. Be sure to push it all the way
back into the guide. Ensure piston is positioned correctly in piston guide.
9. Insert the fastener guide into the baseplate.
10. Align the groove in both the piston guide and baseplate. Slide the baseplate (with
fastener guide) onto the piston guide. Press the shear clip into place. Insert the
piston guide and baseplate assembly into the liner in the tool body. Be sure to align
the groove with the opening for the piston stop.
11. Replace the piston stop and rotate the annular spring into place.
Upon reassembly of the tool perform the following test. Depress the tool against a flat,
hard surface and pull the trigger. The barrel assembly should slide smoothly inside the
tool housing assembly. The firing pin should release after the trigger has been pulled.
CAUTION: THIS TEST SHOULD BE PERFORMED WITHOUT A PIN OR
POWDER LOAD IN THE TOOL.
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