Do poppets wear-out?

[Weaklink]

I have replaced valve poppets due to cracks & breakage.  However, now I have one that I can't see any damage, but refuses to re-seal after re-assembly.

My DAR Gen2 .22 had a slow leak.  I squirted some soapy water around the fill port and a bubble was forming, so I knew the fill check valve was leaking.

I depressurized, disassembled, replaced o-ring, re-lubed everything, and tried to charge back up with a cheap electric compressor and also my hand pump.  Tried several times, even disassembled and reassembled two more times to inspect the valve seat and poppet with magnifying glasses.  I don't see any defects.  Air leaks past valve fast enough that it refused to build pressure.  I assume if I could rapidly dump high pressure into the reservoir, it would probably re-seal, but I don't have a tank.

I even put a spare Marauder poppet in to try.  The stem was 10 thousandths bigger, and a hair shorter, but the poppet appeared the same size and fit in the valve. I was able to get the reservoir to seal and pressurize, no leaks, but would not operate correctly due to the slight stem tolerance differences.

Anywho....  After two hours of fiddling, I'm just perturbed.

[nervoustrigger]

I’ve repaired a lot of PCPs and I can’t say I’ve seen a poppet that failed due to wear.  The one caveat being material and/or tolerances that caused the poppet to extrude into the valve throat.

The DAR poppets have a reputation for cracking.  Could it be a hairline crack that is too small to see?  Because if not, it would mean the leak is at the face which seals to the valve body...and that would be a leak you can repair with lapping. 

[JPSAXNC]

Your being able to fit a stem that was .010 bigger doesn't sound good either. Free play around the stem might not let the poppet seal exactly the same every time. Just a thought.

[Trucker3573]

My DAR did that all the time.  If I had to empty it when I refilled I just pulled the whole tube assembly out and literally while I was working a hand pump with one hand I was jimmying the poppet stem in and out with the other.  It always worked and the gun began to fill even with a hand pump.  Brings back bad memories.  I hated that gun. Worst thing I ever owned. 

[JPSAXNC]

The poppet is a toilet plunger style and the angle is to steep and doesn't come to a knife edge, it's left with a flat. So instead of having a knife edge skirt that can flex to seal, the flat get's beaten flatter and wider, until it's no longer flexible enough to seal. imo

[mandn]

Do you happen to have an exploded view of the DAR2 that you could show ? If not where can I find one.

[Motorhead]

Absolutely !

Seat / sealing surface profile as well the soft side of the seats material make a huge difference in longevity.

[oneshot61]

Mine stopped seating in my armada. Someone told me to use a drill and doing the poppet while pull slightly on it with jb bore paste on the poppet. Reseated and have never had another problem.. may work for you too.