While using my air nailer to build my porch I noticed the gun starting to leak air out of the head of the gun where the two main vents are. I went on-line and did some searching and figured one of the O-rings must have blown.
I called around town and found Quality Tool Repairs stocked an O-Ring Kit for my Stanley Bostitch Air Nailer N80S. The "S" stands for stick nailer and if it were a coil gun it would have a "C" on the end.
The kit cost me $45.00 and contains every O-ring and gasket you will need to rebuild this gun. Down side is there are no instructions so you need to consult your manual and look at the parts diagram for a breakdown of each gasket or O-ring. If you do not have a manual I have uploaded the manual for this gun in the Manuals section found here Stanley Bostitch Manuals - Router Forums
All I needed to remove the head was a hex driver and removed the four M6 x 1.00 screws. Once the head was off I saw my problem right away. The cylinder seal was split in two. When I grab the cylinder seal I noticed it was hard and brittle. I thought to myself, this is too easy. Rather than dis-assemble the entire air gun I decided to just replace the cylinder seal (Part # N70155).
Prior to re-installing the new seal I sprayed the seal with Silicone lubricant. DO NOT USE PETROLEUM BASED LUBRICANTS, THEY WILL DAMAGE YOUR NEW SEALS
. Much to my delight after tightening all of the screws I plugged the air hose back onto the gun and VOILA! no more air leaks. I loaded some nails into the gun and took it for a test run and found it to work flawlessly.
This took me less than 5 minutes to repair and saved me $329.00 for a new gun.
I hope this encourages others to tackle this simple and easy repair.