Resealing the Sheridan Model C

This was a comedy of errors. Basically the Sheridan goes back together in reverse of disassembly, below are notes and comedy that point out a few details.

I used the shim punch to cut concentric seals from lead and rubber.

The inlet valve seal is wrong. I know that now. I cut it way too large in diameter.

You would think I would have caught on...

The exhaust valve spring is tapered, small end towards the rear.

The exhaust valve seal looked clean so I decided to reuse it.

The large rubber washer is also twice as thick as it should be...I thought I had removed the old one but couldn't find it...

At least I got the lead seal right.

The nut is conical to seal against the lead seal.

The face you see when you look down the tube.

Ready to reassemble. I found I had to trim the length of the square section on the wrench to the length of the nut.

That bolt spring...

I placed a feeler gage against it to compress and slid the bolt back in.

Then screwed the locking lug back in. I think it's best if the flats are vertically oriented on the sides so that it smoothly contacts the cam.

The plug goes back in oriented as shown. Then I couldn't screw the valve in...I discovered that the old rubber seal was still in the gun and half as thick as the replacement...preventing me from screwing in the nut (because i now had 3x the thickness)...so I reused the old one and got it all back together.

Well after getting it back together (in reverse of disassembly) it wouldn't work...still not holding air. So I replaced the inlet valve spring with the one on the left. You can see the old rubber seal above the springs

Still no good...so I turned up a new inlet valve seal from teflon. Look familiar? It worked so well in the Benjamin 317 that I figured why not?

You can see how I didn't make good contact with my replacement rubber seal. Well I'll figure it out next one I reseal...note that I put a stem on the teflon seal on the spring/valve end just as I did on the Benjamin 317. I don't know why I did it instead of just making a disc but it may be stronger this way and resist deforming in the center. I do lose a bit of valve volume this way.

Well the gun shoots about 645-650 fps at 8 pumps with Benji .20 cal cylindrical pellets. So it works! It also held air for several days, which is a good test.