depressurize a crosman 150

[bbendel961]

I have a crosman 150 that would not hold CO2 at all. I carefully installed a rebuild kit and found the exhaust valve to be bad. I used plenty of pelgun lube when reassembling. I fired about 15 shots thru it with no issues. Then it quit shooting pellets. I cock the gun and when I fire it, it sounds like there is no CO2 in the powerlet. After removing the hammer assbly, I was able to tap the exhaust valve enough the empty the CO2 out. I looked over the hammer assmbly and could not see an issue.

Second powerlet.

Like a fool, I lubed things up and tried a second powerlet. The first firing punctured the powerlet and pressurized the gun. I still get no CO2 going into the barrel when I fire it. I removed the hammer assmbly and again tapped on the releaf valve to release the CO2. It moved way too easy. As a matter of fact, I can depress the exhaust valve by pushing on it by hand with a punch. No CO2 is released at all. Now What? I have a fully pressurized CO2 gun, I cannot release the pressure, and I cannot disassemble it.

Any Ideas for me?

Thanks
Bill

 

[Felinis]

You said that the air valve was bad but you did not say what you did about it. Did you replace it with stock or modified?

It sounds like a weak air valve spring to me. Did you replace it?

 

[nervoustrig]

Sounds like the stem might have driven through the poppet. Usually when that happens, a slow leak will develop. The fact you can push the stem easily suggests the stem is more of a slip fit than an interference fit so it’s unclear why it isn’t leaking down.

If memory serves, the 150 pressurizes the tube rather than the valve alone, meaning there is too much load on the threads of the endcap to simply unthread it.

My advice would be to grab the stem and rotate it and move it in and out until a leak develops.

 

[bbendel961]

I did replace the leaky exhaust valve and all the o-rings that were in the kit. There is absolutly no leaking of CO2 from around the valve.

Tomorrow night I will try to cause a leak by moving the exhaust valve stem around.

These guns are actually pretty straight forward in how they work but this particular problem is confusing. I take it this type of problem is not very common.

Thanks Bill

 

[marflow 777]

can you unscrew the cap
if you push the valve stem and there is gas it has to go out the barrel
https://support.crosman.com/hc/en-us/article_attachments/201589000/C150-EVP.pdf

 

[JKM6442]

Given your description of what's happened, It sounds like the hammer drove the valve stem through the valve head and out the front. This would answer why you can push the valve stem back and forth. You probably have only two options here: try to pull the valve stem back and all the way out or drill a hole in the tube cap. The hammer driving the valve stem all the way through the valve head could be caused by two things: a defective valve head or a replaced hammer spring that's way to strong.

 

[houston]

Put it in the freezer for a few hours. Remove, and try to loosen cap by hand.

 

[fivestar45]

I believe that Jason has the right idea. However, for me when I had a similar issue it was that the stem had been pushed partly out of the brass toward the striker/hammer resulting in short stroking to the point that the gun couldn't fire.

 

[JKM6442]

Put it in the freezer for a few hours. Remove, and try to loosen cap by hand.

I didn't think that would work but had to see for myself. I loaded a 150 with a new CO2 cartridge and put it in the freezer for about 8 hours. There's no way the cap can be unscrewed by hand and I doubt it could be removed using something like vise grips. But the experimenting isn't over. I have a 20 OZ paintball tank with a full load of CO2 and a valve with a pressure gauge. When I put that in the freezer, the gauge registered 1,000 lbs. I'll report back the pressure after 8-10 hours of chilling.

 

[JKM6442]

I didn't think that would work but had to see for myself. I loaded a 150 with a new CO2 cartridge and put it in the freezer for about 8 hours. There's no way the cap can be unscrewed by hand and I doubt it could be removed using something like vise grips. But the experimenting isn't over. I have a 20 OZ paintball tank with a full load of CO2 and a valve with a pressure gauge. When I put it in the freezer, the gauge registered 1,000 lbs. I'll report back the pressure after 8-10 hours of chilling.

As stated, the paintball tank went into the freezer at 1,000 lbs PSI; it came out at 300 lbs PSI. The freezer temp is 0 degrees Fahrenheit.

 

[nervoustrig]

As stated, the paintball tank went into the freezer at 1,000 lbs PSI; it came out at 300 lbs PSI. The freezer temp is 0 degrees Fahrenheit.

Very nice, right where the pressure chart predicts...

 

[JKM6442]

The point I was trying to make with my comments about CO2 pressure is that, in my opinion, the easiest and safest way to de-pressurize the pistol is to drill a hole in the tube cap.