Monday, January 4, 2010

Benjamin Model 132 Pistol Disassembly, Part 3

Almost done...

Removing the breech cap screws.

The breech cap and hammer spring come out.

I removed the "bolt button" from the bolt.

The hammer slid out as well.

The face of the hammer.

Getting the bolt out requires removing the "bolt guide screw".

A small screwdriver through the tube does the job.

When removing the bolt, as with every other Benjamin or Sheridan, don't space out and allow the spring or (only in the case of the Benjamins) ball bearing to spring up and out into the wild. Notice how shiny the ball is? That's because it's new. Good thing I have a supply of bearing balls on hand.

Notice there's no seal on the bolt.

I used my home made valve tool to remove the outlet valve lock screw.

And my home made valve puller to remove the rest of the valve unit.

The lead seal is in good shape, notice the alignment tab on both the seal and the outlet valve. There's another lead seal still stuck in the tube that I'll leave in place, it's swaged in there and likely will seal fine. if not then I'll tear it out and install a new one. But I'm nowhere near there yet...

I ground the tip of some music wire to fit in the inlet valve hole.

And carefully inserted it into the inlet valve hole.

Which pushed out the inlet valve. I have yet to have one just come out easily...

Typical seal extrusion...I'll be making a teflon replacement.

Back to the pump plunger. It looked to be in good shape but it turned out to be torn...

I managed to put enough torque on it to remove the pump rod screw.

Thus ends the disassembly. According to the drawing in Fletcher's book there should be a washer between the pump expander and the leather cup. But who knows whether they always used those.

Now it needs a new inlet seal, a new pump cup, a lead seal (although I could likely reuse that one), reseal the exhaust valve (I forgot to take pics but it was hard and grooved...) then clean and reassemble. I'm almost done with all of that although fabricating the pump cup is giving me fits. But that's a story for another time.

7 comments:

Anonymous said...

what size ball bearing is that and where does it go? under the spring im asuming?

GoronZero said...

what size is that ball bearing?

Anonymous said...

What size thread for the valve?

Nick Carter said...

The stem thread?
9/32"-32 tpi

The larger thread? Didn't bother measuring it.

James VonDeck said...

Has anyone ever see a early benji 132 with checkersd wooden grips?

Dennis Harrison said...

Great write-up. I got parts to rebuild and followed your steps but when I finished the pellet did not come out. Any ideas what I did wrong? Thanks

Felice Luftschein said...

Hard to say, sometimes you need to start over again and make sure that it's pumping air, storing the air and then transferring the air to the pellet.
Nick