Overview
This replacement piston driver is manufactured to OEM specifications for pneumatic and battery-powered nailers. A worn piston driver is one of the most common causes of inconsistent nail depth and tool jams. Swapping in a new driver assembly is a cost-effective repair that extends the working life of your nailer significantly.
Key specifications
- Aftermarket piston driver assembly
- Direct OEM-equivalent replacement
- Includes o-ring(s) for proper cylinder seal
- Precision-machined for consistent nail depth
Compatibility
This piston driver is designed to fit compatible equipment nailers as specified in the compatibility listing above. Always cross-reference the full model and type number stamped on your tool’s nameplate before ordering.
Installation notes
Always depressurize the nailer and disconnect power before servicing internal components. Access the piston driver by removing the cylinder end cap and nose assembly. Apply a light coat of pneumatic oil to the replacement driver’s o-ring before reassembly to ensure a good seal from the first shot.
Common questions
Q: Will this 885917 piston driver blade fit my Hitachi/Metabo HPT NR90ADS1 or NR90ADPR framing strip nailer?
Yes. This piston driver blade is listed for the NR90ADS1, NR90AD(S1), NR90ADS1M, NR90AD, and NR90ADPR framing strip nailers, and it replaces part numbers 885-917, 884-957, and 885917. If your original driver matches those model and part references, this is the correct replacement style.
Q: I have an NR90AD that misfires and the driver blade stays down sometimes—would replacing the 885917 piston driver blade help?
It can if the driver blade is bent, chipped, worn short, or separating from the piston. Those issues commonly cause poor nail feeding, incomplete driving, or the driver not returning properly. While you have the tool apart, also inspect the cylinder, piston ring, and bumper since wear in those parts can cause similar symptoms.
Q: Is there anything important to check when installing this 885917 piston driver blade in an NR90ADS1M?
Make sure the old blade and piston assembly are removed cleanly and check for damage inside the cylinder before installing the new part. The driver must move freely without binding, and it’s a good idea to replace worn seals or the bumper at the same time so the new blade isn’t damaged by excessive play or hard bottoming out.
