stuck piston

[clong1946]

I have a porter cable rn175 coil nailer. when you pull the triger the piston fires but it will not return. it stays in the down position. I have installed a rebuild kit part #60075 but this did not help. Also the nailmover piston retracts and slowly moves the next nail into the fireing position.Help please!!

[bec98x]

The nail driver not returning could be several things. Check the o-ring around the cylinder which covers little holes.

Check the driver o-ring and make sure it moves freely.

Does the nailer leak air? Plant the nose on a piece of wood and hold it down. Pull trigger and hold. Driver should stay down and you should not have any air leaking. Sometimes when it leaks out the nose you have a bad bumper.

As far as the feeder goes....

Your best bet is to pull out the feed piston and check for chunks of the bumper blocking the air passage. Also check to make sure the piston is straight and that it moves freely.

I have had a few of those that the nose was actually bent. If I loosened up the nose screws about 1/2 turn then then feed piston would retract properly.

[EngineerJim]

To add the the previous post, you will need to remove the piston cylinder. About 1/3 up there are a series of small holes around the circumfrence of the piston. They are covered by what looks like a wide elastic band. When the piston fires and gets past these holes air is allowed to bleed into the lower pressure chamber. ( the band flares outward acting as a 1 way valve) For the return stroke the pressure in the piston is vented, This leaves the lower chamber charged with compressed air which is what drives the cylinder back up. This air also powers the nail feed cylinder.
So - Check that the holes are not blocked and that the " elastic band" is sealing off these holes to prevent air from leaking back into the piston chamber.
if they are ok then you have a leak in the bumper seal or somewhere else in the lower chamber.