Saturday, November 1, 2008

Getting a Crosman 140 Working, Part 6

So the 140 stopped pumping up...I could hear air rushing past the pump cup.

Punching out the pivot pin.

The pivot plug.

The pump cup (remember, it's a 101 pump head, and a replacement seal of unknown provenance). It didn't look bad but seemed floppy, not stiff.

Some 95 durometer urethane rod being faced with my extreme knife tool. I ground a bunch of tools that have around 60 degrees rake, more or less.

Drilling it out.

Boring the minor diameter.

Setting the compound to about 5.5 degrees.

Turning the OD with a similar knife edge tool.

The new cup is the middle one. Left is the one that came with the 101.

I assembled it but it seemed overly tight. I also forgot the bevelled edge on the face. So I disassembled again and mounted it on a broken pump rod. I cut the bevel and turned the OD slightly smaller.
I put it all back together and pumped it up 10 times. Air was leaking past the bolt. Shot again and the bolt shot under the cover (no pic, I was having an adrenaline rush) which was a bit dramatic.

So I refurbished the bolt cover with a hole on the other end and less clearance for the locking lug, and used the old screw from my 150 (it has a head so won't allow the bolt to sneak under the cover). Anyway, I just "won" an original bolt cover on Ebay, so when it comes I'll make a new screw and it should be close to perfect (?).

I pumped it up 10 times and got 636 fps, which is great. I think if I tighten up the bolt seal and maybe clean up the flow through bolt a bit it will gain a little more. Unless something else goes wrong...I am happy I was able to make a pump cup, which is a skill that should come in handy for other projects.


Anonymous said...

I love your blog, very interesting and very well documented (photos, explanations).



Roy said...
This comment has been removed by the author.
Roy said...

I have a crosman 140 and i am trying to find out how to replace the pump rod cup seal. Any information would be greatly appreciated. Thanks

Felice Luftschein said...

Shows the type of pressing tool you need to make.

Roy said...

AWESOME thank you

Anonymous said...

I know this is an old blog but I am also trying to replace the cup seal on my 140 but with no luck.That link dosent work anymore, do you no of another video?

Nick Carter said...

I can't find another video, best thing is to ask on the Crosman forum.