discovery fill problems... help please

[arlessinfl]

I am new to pcps. I bought a 177 disco last week and it has been fine. It was a rifle and pump combo.

I liked it so much that I picked up another in 22. That was when the problems began.

At first, I could not get it filled. I tried pumping for a few minutes at a time but could get no air into the chamber. There is a loud whooshing sound. I think that it is coming from the muzzle. I called crosman customer service and the lady said that it was likely a valve not being able to close and if I can find a fill tank, the high volume of air will be able to get the valve shut and allow it to fill.

Frustrated, I thought about it and figured that I may be able to do this mechanically. So I slapped the buttstock hard with my hands several times. Imagine my surprise when it started to fill!!!

I shoot a few dozen shots through it and left it at about 1500 psi. I checked it about two hours later and it had dropped down to about 1000. This morning it was completely empty. I tried to fill it back up and it would not fill! This time the site was not leaking out so fast and it could definitely stop the whooshing sound when I put my finger on the muzzle.

Help please...
What is wrong? Will crosman fix this or will I need to return it to the retailer?

Thanks so much in advance.

[Ribbonstone]

Will try the simplest first.

Cock the bolt before trying to fill the rifle.

IF you can fill it again, then fill it all the way to 2000psi and leave it there.

Not too unusual for the gun to cool off right after filling and show a little drop in pressure from that cooling, so don't freak out if it shows a small drop 15min. after filling.


IDea is that the valve stem may not make a perfect seal, but that some time being mashed against its seat by bull pressure can make it seal.

[arlessinfl]

Thanks for the reply.

This morning, it was done to zero.

I was not able to fill it this morning either (cocked or uncocked) until I whacked the buttstock a few times again. I filled it to 1200 and took a couple of shots. I put the gun to my ears and could hear a hissing sound at the muzzle.

I will check it again in about an hour, but I expect it to be at our near zero.

[Ribbonstone]

Fill it to 2K and listen for that hiss.

Only one thing will make a Disco leak from the muzzle: valve stem seal not sealing.   

[arlessinfl]

I pumped it up to a little bit over 2000 last night and no longer heard the hiss.
It dropped a little by morning, but I am not sure if it is due to the cooling effect or leaking, so I will check it again this evening.

I hope that this will fix it since before last evening, it would go completely empty in a couple of hours.

[Geoff]

going out on a limb here .. the fill port may be sticking .. you could remove it and clean the fill nipple to try to solve the leak.

one thing that you can guarantee is ALL PCP's WILL leak eventually and need new orings or TLC