HELP-crosman 1377 pistol problem

[ggggr]

Got a 1377 pistol which I was told wasnt working. Never had one apart so fancied it. When you pumped it, you could feel the pressure build up and it was ok if you fired it pretty quick but power fell very quick if you left it about 15-20 seconds. Wouldnt hold charge overnight. Stripped it and took valve boddy apart. All thats in it is a piece of tapered plastic(inlet valve?) a small pieced of aluminium,a spring and what looks like a brass adapter for blowing up a football(exhaust valve or what?). Its about inch and a half long and looks like it may have a small o ring where it seats in that half of the pump body. Phoned chambers (no diagram for it and not much for 1300) to order some bits. The plastic piece is longer than the original, About as long as the original and the aluminium piece,so Im assuming it is ment to replace both? The exhaust bit looked nothing like the one in mine so I couldnt fit it. Anyway I put it back together and it was worse. I think the taper on the plastic may be different. Phoned a few places and one of them suggested here!
Any crosman experts? I dont know if Ive got original valve body or not,or whether interchangable. I could do with a small inlet piece( about 1/4 inch long + the exhaust bit) I dont want to spend £25 on a new valve when I should be able to sort it for a few quid.
OVER TO YOU FOR ANY ADVICE OR SPARES THAT WILL DO THE JOB.
Its only going to be a plinker and I may pass it on to my mates lad.

[lightning22]

Pics would be useful.

Rich

[deebee]

Try Steve on here. One of he good guys

http://www.sdcustomdesign.com/index.htm

Dave

[T 20]

Hi ggggr
The long inlet valve you describe is a direct replacement for the short plastic valve and aluminium spacer.It sounds like your exhaust valve may be leaking, this valve has also changed from a brass head with rubber insert to a teflon valve. All the parts diagrams are available to download on Crosman.com customer services, the valves are all available from S D customdesign. The website hotrod 13xx gives good pictures of the differences in the old and new type valves and also shows how to tune these guns. Don't forget to replace the O ring round the middle of the valve as a small cut in this can cause an air leak.
If air is leaking into the pump the inlet valve is faulty, if the leak is into the barrel the exhaust valve is at fault. The angle of the inlet valve has not changed in over 50 years but the valve lengths have changed from gun to gun over the years.
If your inlet valve is leaking it may need lapping in to the valve body, you need some way of turning the inlet valve inside the body. to do this I normally cut a slot on the back of the valve with a hacksaw so that it can be turned with a screwdriver. You need to use a very mild abrasive to lap the valves in, I use CIF or toothpaste (not joking), the valve seat and valve when lapped will be cleaned and pollished and a perfect seal when done. The exhaust valve can be lapped in the same way by rotating it with the valve stem when it's installed in the valve. Wash all the components of the valve assembly with warm water and dry, oil the valves and screw back together and fit into the gun. This should cure the problem, the Crosman valves and pump rely on being clean and oiled to work properly, I always leave the Valve with one pump in it when I put it away. I have never had to buy a new valve after 30 years of owning Crosmans, if you lived nearer I'd sort it out for you, but anymore help you need just ask.
Cheers Mick
PS I've just had to fit a stock to my 1377 as it's doing 750 fps
PPS the first 3 or 4 digits of the serial number of your Crosman are its date of birth

[ggggr]

Thanks for info,people. Just looked at website and the valve stem is the same as mine. Will probably have a go at lapping in( was going to do it before being warned off). Id like to fit a slightly longer barrel as well-about 4 to 6 inches longer. Do they do them for the 1377 and is the breech block in with it or does that pull apart. Thanks once again for help.

[T 20]

14 inch barrels are about 20 quid.
Custom Crosman breaches are about 30 quid.
Best to go for .22 as they are more efficient power wise and easier to load.
You need to drill out the foresight for a longer barrel.
Go steady with the lapping you only need to achieve a light polish.
what age is the gun by the way?
Cheers Mick

[deebee]

Thanks for info,people. Just looked at website and the valve stem is the same as mine. Will probably have a go at lapping in( was going to do it before being warned off). Id like to fit a slightly longer barrel as well-about 4 to 6 inches longer. Do they do them for the 1377 and is the breech block in with it or does that pull apart. Thanks once again for help.

Like this you mean?


http://i235.photobucket.com/albums/e...tomCarbine.jpg

Shoots really well
Dave

[medalist]

leaking air. my brother oiled the crap out of it well thats the least i know. took her apart cleand her up after 18 years never had a problem until now; and she still leaking. i love my time with my 2 air guns and this sucks. need a good tutor to talk me threw this im hoping. also have a 1377phase 2 she is perfect but wouldent mind increasing fps any tips.

[Garvin]

leaking air. my brother oiled the crap out of it well thats the least i know. took her apart cleand her up after 18 years never had a problem until now; and she still leaking. i love my time with my 2 air guns and this sucks. need a good tutor to talk me threw this im hoping. also have a 1377phase 2 she is perfect but wouldent mind increasing fps any tips.

Have you checked out this forum, there's lots of the kind of expertise you need there?

[T 20]

leaking air. my brother oiled the crap out of it well thats the least i know. took her apart cleand her up after 18 years never had a problem until now; and she still leaking. i love my time with my 2 air guns and this sucks. need a good tutor to talk me threw this im hoping. also have a 1377phase 2 she is perfect but wouldent mind increasing fps any tips.

Hi Medalist
The valve unit in the 1300 medalist has 4 imperial sized O rings in it and a plastic check valve.
The O rings should be easily obtainable from a hardware shop and the check valve is the same as the check valve used in the current 1377.
The most difficult part of the valve rebuild is fitting the O ring to the exhaust valve cap.
The original exhaust seal should be a quad seal but it is acceptable to use a standard O ring instead.
It would also be worth checking that the sear hasn't been deformed from the valve being hydaulicly locked.
It may also be worth slightly stretching the return spring for the exhaust or fitting a new one.

With regards to increasing the power of your 1377 I would go with Garvin's suggestion of looking on the Green forum.

I would also have a look on here

http:www.airguninfo.com/


It would also be worth looking at this

www.mp661K.com/sitedocs/13xx_HotRod.pdf


Hope this helps

All the best Mick