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rsterne · Moderator

About a year ago I bought this 1400 as a project (like I didn't have enough already).... I'm a sucker for the wood on these early Crosmans, you never know what's hiding under there.... I've already rebuilt a few 140s, so I'm familiar with what they need and like.... When I bought this gun the Ad said "nice brown patina" and I should have known what that meant....

Actually the rust wasn't that bad, mostly in front of the stock where people have a tendency to pick up the gun when it's propped in a corner.... The wood is covered by Crosman's brown finish of the time but the grain underneath looks nice.... It wouldn't hold air for long and shot weakly (under 500 fps) so I pulled it apart just to diagnose it and found the quad seal leaking and replaced it.... That gave me a gun that would hold air and shoot typical of a gun of that age....320 fps at 2 pumps, 440 at 4, 510 at 6, 550 at 8, and 580 at 10 pumps.... The trigger pull was attrocious, but at least the metal trigger group on the 1400 is adjustable for pull weight where the 140 (which has the trigger mounted directly in the wood stock) was not.... I stripped the gun completely apart to start the rebuild.... Here are the parts of interest....

Starting from the top, looking at the items circled in yellow....

The cutout in the pump tube is too far forward and if you don't pump the gun VERY slowly it doesn't take in air properly as the air has to draw into the pump along the raised channel.... This is a common problem where the velocity is low unless you wait a couple seconds at the end of each "out" stroke.... The solution is to lengthen the slot and deburr it carefully....

The pump cup is difficult to replace, and this one is quite hard.... My solution is to replace the end half of the piston with a new flat topped one grooved for an O-ring.... Easily replaceable, commonly available, and you can achieve higher pressures....

The rear of the valve only has a 1/8" hole in it.... I drill it out in stages to 5/32" to match the rest of the ports in the gun....

There is an aluminum spacer in the valve which takes up about half the volume.... This means that the pressure rises very quickly, but you will notice that you get most of the performance in the first 6 pumps.... With the "dump" style valve held closed directly by the sear, the higher the pressure the harder the trigger pull.... I will be replacing the short spring and spacer with the longer one underneath them.... The additional volume will allow more velocity at higher pump numbers with reduced trigger pull weight....

The hole in the flow-through bolt is only 0.140".... I drill it out to 5/32" to match the other ports....

The stock retaining screw in this gun wasn't all mangled by pliers, so it may never have been apart.... They are usually shredded by master craftsmen, however, so I mill two flats in the larger portion to allow the use of a wrench to remove and install....

Other than these items, everything will get a thorough cleaning, rust removal, and rebluing and then I get to tackle the stock....

Bob

Crosman140 · Senior Member

I look forward to your progress. I still haven't refinished my 140 because I accidentally left it in another state when I moved. My dad has the gun now and when he visits, he'll be bringing it with him.

If you wouldn't mind, post lots of step-by-step pictures and instructions. I think I have one of your other projects saved in my favorites, but it never hurts to have more projects to use as guides.

rsterne · Moderator

Not sure what might help in the way of "step-by-step" photos and instructions.... Today I sanded all the bluing and rust from the barrel and main tube, polished them to 320 grit equivalvent using a 3M Scotchbrite pad (maroon) and then reblued them.... My cold bluing process is as follows:

Clean by sanding or wire brush, finishing larger items with at least 320 grit equivalvent 3M Scotchbrite pad (maroon)....
Degrease with solvent (varsol)....
Wash with hot soapy water and blow dry with an airhose....
Put on gloves to prevent fingerprints and protect hands from bluing solution....
Wash with Methanol and blow dry....
Apply Van's Gun Blue liberally with cotton swabs/ Q-tips.... on large items, do a few inches at a time....
If the metal is stubborn, heat it up with a hair drier....
Use an ultrafine 3M Scotchbrite pad (white) to blend the colour....
Apply more bluing to darken if required....
Wash thoroughly in hot water to neutralize the reaction and blow dry....
Apply a good gun oil (Hoppes, etc.) to "set" the bluing.... coat thoroughly and wipe dry.... If you don't do this, the item WILL rust....

I've found the Van's Gun Blue works the best for me, I haven't had luck with Birchwood Casey.... YMMV....
I FAR prefer using the 3M Scotchbrite pads to steel wool.... cleaner, gentler, and they don't fall apart.... again, YMMV....

Bob

Crosman140 · Senior Member

I've done a little cold bluing too and found that steel wool was messy...they sort of fall apart and leave little metal fragments everywhere. I'll have to try the scotchbrite pads. I'm familiar with those are can see where they would work nicely and be much more clean.

I'm not a huge fan of cold bluing as they seem to rust. I oil the blued parts and try not to touch as much as possible. But the cold bluing just doesn't seem to hold up like the original hot-blue process. Could be the brand I used at the time.

Thanks for the instructions.

radar · Silver Status Member

Cool! Another project!

I find that Brownell's cold bluing solution and heating the metal a bit makes a good protective bluing. Just my experience. It make a lot of nasty fumes though, so be careful of that.

rsterne · Moderator

Over the past couple of days I have been working on the modifications I wanted to do and rebluing all the metalwork.... Every single piece was cleaned, degreased (twice) and reblued with Van's Gun Blue.... There were a lot of small pieces....

In addition I reblued the barrel, main tube, and pump linkage.... In the photo above you can see the new piston with O-ring (top right), and just below it the stock mounting bolt with the flats milled in it (hard to see).... Once everything was finished and oiled lightly I reassembled the gun and ran a few pellets through it....

If you compare the photo above to the first one in this thread, you can see the improvement.... I was quite pleased with the increase in performance as well.... 2 pumps gave 305 fps, 4 gave 442, 6 was 534, 8 was 588, and 10 pumps was 620 fps.... The gun now shoots harder at 8 pumps than it did originally at 10 pumps.... and the trigger pull is much lighter as well.... I'm quite pleased with the results.... Now to get on with refinishing the stock....

Bob

rsterne · Moderator

I got the old brown finish stripped off the stock today.... Pretty nice grain hiding under there....

Staining and sanding tomorrow, hopefully....

Bob

oddtodd · Silver Status Member

Lookin good Bob!!

radar · Silver Status Member

The stock is going to be nice. Did you mod anything to boost the velocity?

rsterne · Moderator

Just mildly.... drilled out the back of the valve and the flow-through bolt.... removed the aluminum spacer from the valve.... and changed it to an F-T-P.... It now shoots 588 at 8 pumps instead of 580 at 10 pumps.... and 620 at 10 pumps.... With lighter trigger pull....

Bob

Crosman140 · Senior Member

That wood looks nice. These old guns were really made nice. Funny that they covered them up with all that nasty brown junk.

rsterne · Moderator

Pretty similar, really (less at 8, more at 10, which is weird).... I've done a couple of 140s that were stronger, I didn't spend a lot of time modding this one.... just evened out the passages....

Bob

Crosman140 · Senior Member

rsterne · Moderator

I stained it yesterday, dark walnut.... WOW!!!.... don't know if I should post a teaser photo or wait until I have the Watco Danish Oil finish done....

Bob

SMP · Silver Status Member

C'mon stop teasin' I wanna see it

This is cruel and unusual punishment Mr. Green