My tuned and modded QB79 gave up on me :(

[poil27]

i havent open up my qb yet so i can't hanser that. but yo got a good point . i will remember the way it was put in when i'll tune the lady up

[AirGunEric]

The block can be put in backwards- but I don't have one handy to see if the spacing would cause the hammer to not strike the valvestem- will check that later if I remember.

[Dukemeister]

If installed backwards, the valve wouldn't line up... both at the TP and the screw (0500) at the bottom.

[rsterne]

Ah well, it was just a thought....

Bob

[FRANK]

instaled all my new seals , got 5 shoots out of it and it did the same thing stop firering.
I think I will go out side and grab it by the barrel and wrap it around a tree! FKPOS

[AirGunEric]

Seals won't lock a gun up- you have something going on with the valve/hammer- look there for issues (and a teardown/re-do without figuring it out obviously isn't working)- find out what was done to the valve- and if you are using HPA, try reducing the pressure and see what happens.

[SeanMP]

Have an eye at the sear as well. It needs to be very free. If its not it can slow the hammer down enough to cause a misfire. That particular problem has driven me round the bend a couple of times.

[FRANK]

The valve seems to be my problem, let me explain.

The inner valve the one with the rod and white plastic , well the plastic part on it moves alot so I think it makes too much presure since it's pressing more on the spring
and the hammer can't puch the valve, but now here is the funny part during my test I took the stud that holds the the stock to the airgun and I saw the metal part of the valve move
about 1/8 of a inch so I'm at a lost, I got it all apart now and I will instal a valve in it see what happends.

but I got too much stuff to do s oit has to wait it's turn.

[Dukemeister]

http://scopesandammo.com/storefront/...alvestem-p-724
Click, pay, replace......

[rsterne]

The inner valve the one with the rod and white plastic

HUH?.... QB valves are a steel stem with a brass head and contain a clear plastic seal.... It sounds like your QB79 has something different.... I wonder if the stem is the wrong length?....

Bob