How to Replace the Piston Ring on a DeWALT Brad Nailer

The piston ring seals the piston to the cylinder. When the gun is fired, this pressure drives the piston down the cylinder. Over time, the piston ring will wear and the seal will be lost. This can cause the driver to lose power or not drive at all.

Let's get started.

REMOVING THE PISTON RING   1. Remove the top cap from the nail gun. 2. Remove the piston from the nail gun.
3. Remove the piston ring from the piston.  

INSTALLING THE NEW PISTON RING   4. Place the piston ring over the top of the piston. 5. Carefully work the piston ring into position (without cracking it).
6. Install the assembly back into the gun. (Notice there are grooves in the driver. Those grooves need to go back toward the rear of the gun.) 7. Insert the piston into the cylinder (aligning the driver).

REASSEMBLING THE UNIT   8. Place the gasket onto the top of the gun.
9. Install the head valve.
10. Install the screws to align the head valve to the gasket and tighten them up.