Bobcat

[Mechanical musket 7.62]

Little problem with fx bobcat ,when filling air comes rushing out of barrel ,any ideas please

 

[oneshot]

Have you tried cocking it as its doing this

 

[Mechanical musket 7.62]

Yes but it's got a floating hammer so doesn't make any difference

 

[Blackmax]

Little problem with fx bobcat ,when filling air comes rushing out of barrel ,any ideas please

Must be valve related if it’s going down the barrel and the hammer isn’t resting on the valve.

 

[nightowl]

Put a pellet in the barrel, i have had to ise this method befere, ,to give the air pressure enough timeto push the valve on to the seat to seal it, obviousely take in to account,f ,you actually have a pellet in the barrel and its bezt done with the muzzle facing down on a block of 3,x2 or the such
Nightowl

 

[Mechanical musket 7.62]

Put a pellet in the barrel, i have had to ise this method befere, ,to give the air pressure enough timeto push the valve on to the seat to seal it, obviousely take in to account,f ,you actually have a pellet in the barrel and its bezt done with the muzzle facing down on a block of 3,x2 or the such
Nightowl

Thank you I'll try that

 

[nightowl]

Thank you I'll try that

Ivebhad to use this way on several pcps over the years, when cocking doesntbhold the valve shut enough, to seal
Let us know how you get on
Nightowl

 

[Mechanical musket 7.62]

Have replaced valve seat ,new o ring on valve stem still blowing air up barrel

 

[sagalout]

Are you using a sharp blast of air to start the filling process (ie a bottle) or a compressor/pump?

 

[Mechanical musket 7.62]

Yes off a bottle ,still rushes up barrel ,have opened tap on bottle to give over 200 bar makes no difference

 

[sagalout]

It's definitely air passing the valve, it's the only way air can get to the barrel. Have you got any pictures of the bob cat valve?

 

[Mechanical musket 7.62]

When i take it out again I'll show you

 

[V1ktor]

I'm watching this with interest. I too have a Mk1 Bobcat that exhibits exactly the same issue. I spent more than a few quid replacing valves, valve seats, O rings etc. I never managed to resolve the issue.
I happened to drop on a Mk2, the regulated one, and parked the Mk1 in hard case where it has sat since.

 

[V1ktor]

I have a picture of the valvepin and valve seat.

 

[sagalout]

That's the same design as the Crown, different part numbers. The last Crown valve and seat I bought from SGC was incorrect and wouldn't seal. The pin seal (black delrin?) was larger diameter (8mm instead of 7mm).

SGC were adamant that the parts come in from FX bagged and labelled so couldn't be wrong. They did take them back as a return and refunded me.

@Mechanical musket 7.62 have got the seat in the correct way up? From memory the sealing O ring is lower down on the hammer facing side as per your photo of the white one. I assume the white pin is the old one? I assume that because the Crown MK1 had the white (delrin?) seal.

 

[JLB]

Just had a similar issue with an Impact. The delrin on the valve stem is machined square and wouldn't seal in the conical valve seat, I ended up putting a very small chamfer on the delrin sealing face which fixed it. You will need a lathe though.

John.

 

[Mechanical musket 7.62]

Have just removed valve seat and valve AGAIN polished mating surfaces, cleaned, new orings and lubed, still p*using out barrel ,think it's destined for the bin

 

[the logun-ator]

Got a vermy in sane issue. It has to be seat, valve or block issue.
This one's got a new seat and valve (owner fitted)
Going to replace them with one if mine that I know work and if it leaks it has to be the block.

 

[V1ktor]

I should add that the top pin (black delrin) and seat is from my .22 Bobcat.

The pack came with 2 valvepins and 3 valve seats.
7015 - valvepin complete
7019 - SHP valvepin complete
.30 valvepin complete
7044 - valveseat complete
19060 - SHP valveseat complete
19217 - .30 valveseat complete

The delrin on pin 7015 measures 5.78mm dia.
The delrin on pin 7019 measures 6.88mm dia.

 

[Mechanical musket 7.62]

7044 is the same as one i replaced and 7015 is valve stem ,can't understand why suddenly leaking air