Finally got the motivation to finish the door install that we put in shortly after we moved. Door has been hung for a while, but haven't finished the trim.
Got all the materials & was ready to go.

Hooked up my finish nailer, got 1 tedt shot to check nail depth, and it just vents out the back.

Pull the back cover & the wax [or whatever it is] buffer is dried out & disintegrated when I pulled the cover.

Luckily, looks like rebuild kits are available for it.

I had the exact same thing happen with a Brad nailer. Bought the rebuild kit and it came with about ten different o rings and washers. I used one or two and it was back in business.

I think it's just the wax ring/buffer/whatever it is, that needs replaced. May try to source it alone, instead of the full overhaul kit

yep, I'll bet you're right .

Have had that happened to several of my older guns. Problem is I'm starting to have trouble finding kits for my older Bostitch brad nailers. If you plan on keeping yours for awhile might be smart to buy a complete kit while they're available.

Mine's a Porter Cable, that I think I've only used once.
Looking yesterday, I found tons of overhaul kits ranging from $40-90, so for the moment, they're plentiful.