HW100 Losing Air from underneath barrel block.

[bossmugler]

Hi all

I hope everyone is well in these uncertain times. Apologies for my absence,but due to working as a Biomed Scientist in an NHS lab I have been rushed of my feet with the COVID-19 pandemic and therefore haven't so much as touched an airgun since March..

Anyway I digress. I had a bit of spare time and fancied a bit of plinking in the back yard, so I grabbed the trusty HW100, which was still showing 100 bar fill. Popped in a mag and cycled the pellet and fired the first shot. No problem, fired the second shot and the pellet dropped about a foot? I thought , hello somethings not right here. Cycled the mag again, pulled the trigger nothing, cycled the mag again, fired and nothing. Third time it fired and three pellets shot out , at greatly reduced speed.

I didn't think this was possible due to the HW anti double load feature? I then topped up the air cylinder to 200bar, thinking it might be an air pressure problem, with the gun laying idle for months a. Upon reaching 200 bar there was a loud constant hiss of air, which continued until the air cylinder showed 100 bar. I changed the two O-rings on the valve stem and underneath it, as a precaution, so I know its not that. Upon removing the action from the stock and putting my ear to the action. I noticed that air was escaping from one of the two adjacent small holes directly underneath the barrel block and towards where the cylinder is screwed into. I think it is some sort of pressure release valve or something?

So my question to the enlightened BBS collective is, could you please tell me how I set about correcting this fault and what parts and tools I would need? Or is there a video showing how to solve this problem.
I suspect it might be a job for a qualified gunsmith?


Many thanks in advance.

Ian

[Bladerunner too]

Get a seal kit, looks complicated https://www.gunspares.co.uk/products/24752/HW100/ But its not.

[Edtwozeronine]

Hi all

I hope everyone is well in these uncertain times. Apologies for my absence,but due to working as a Biomed Scientist in an NHS lab I have been rushed of my feet with the COVID-19 pandemic and therefore haven't so much as touched an airgun since March..

Anyway I digress. I had a bit of spare time and fancied a bit of plinking in the back yard, so I grabbed the trusty HW100, which was still showing 100 bar fill. Popped in a mag and cycled the pellet and fired the first shot. No problem, fired the second shot and the pellet dropped about a foot? I thought , hello somethings not right here. Cycled the mag again, pulled the trigger nothing, cycled the mag again, fired and nothing. Third time it fired and three pellets shot out , at greatly reduced speed.

I didn't think this was possible due to the HW anti double load feature? I then topped up the air cylinder to 200bar, thinking it might be an air pressure problem, with the gun laying idle for months a. Upon reaching 200 bar there was a loud constant hiss of air, which continued until the air cylinder showed 100 bar. I changed the two O-rings on the valve stem and underneath it, as a precaution, so I know its not that. Upon removing the action from the stock and putting my ear to the action. I noticed that air was escaping from one of the two adjacent small holes directly underneath the barrel block and towards where the cylinder is screwed into. I think it is some sort of pressure release valve or something?

So my question to the enlightened BBS collective is, could you please tell me how I set about correcting this fault and what parts and tools I would need? Or is there a video showing how to solve this problem.
I suspect it might be a job for a qualified gunsmith?


Many thanks in advance.

Ian

Send it back to Hull Cartridge for a service, sounds like more than just air leaking if it's allowing you to cock and load more than 1 pellet into it. Mine was cocking/loading/firing sporadically before a service circa 2016, came back good as new! More recently I did the seals on the air cylinder myself but I wish i hadn't, it was a ballache and I scratched the outside of my cylinder with a 36mm socket I borrowed from my Dad's collection. Still working though, on the bright side...

[bossmugler]

Hi thanks for the reply

I have a seal kit, but how do I take the gun apart to fix it. Whats the procedure, so I don't damage the airgun ?

[madcarlos]

Hi thanks for the reply

I have a seal kit, but how do I take the gun apart to fix it. Whats the procedure, so I don't damage the airgun ?

Hi bud there should be plenty advice on YouTube etc or someone could advise you on here , I've worked on some of mine over the years but I wont attempt to do anything unless I'm fully confident and have searched enough info etc, If you can do that then great, It can be enjoyable sometimes, On the other hand there are plenty of people on the forums who does gun services / repairs etc, Always worth asking if you decide not to have a go yourself ok bud,

[Shed tuner]

yes.. I think if you are not confident, then take it to a gunsmith / Hull Cartridge. PCPs are much more dangerous than springers if you make a mistake.

Also the double load thing - as I understand you did cock and fire each time, so that's not a double loading mechanism fault.

[bossmugler]

Thanks for the advice guys.

Bit of a noob regarding Hull Cartridge. Do I get a courier to deliver it to HC, as not familiar with sending air rifles to be repaired. Also what's the usual turn around time? I suppose COVID with delay it quite considerably?

[metalmickey]

Hi Ian. I have just overhauled a HW 100 for exactly the same concern. albeit that this one was a 2002 model and never been serviced. Your problem is that the air from the cylinder is not entering the regulator !!!
This is caused by the spring loaded ball bearing sticking to the "O" ring seal inside the brass inlet valve. If the gun has sat un-used or is over a certain age the "O" ring seals go hard and the ball bearing sticks to the "collapsed" seal face.
Remove air bottle (if this is a later quick fill with the valve in it you do not need to empty the cylinder as this will seal off as you remove it) Using a 10mm deep socket remove the brass inlet valve unit. separate the retaining nut 8mm ?
Get a replacement Inlet valve service kit (HW100tuning) off their website. Replace the "O" ring ball & spring. If in doubt look up on You tube Mr HEALY has a 2 part video of a full overhaul of the HW100. Warning do not open up the regulator unless you have a gauge to re-set it up. Good luck

[Harley_Steve]

Another vote for Martin Healey's videos.

[Bladerunner too]

get plenty of info here,https://www.tapatalk.com/groups/weih...ners/index.php

[bossmugler]

Many thanks for the replies gents. Its greatly appreciated and I will order the kit asap.

I have also ordered a Regulator Pressure Test Port Seal Kit from HW100tuning, because that o-ring had also perished. This kit also negates the ball bearing,as you just screw it in with the o-ring attached and without needing to take apart the regulator. It shouldn't need calibrating with a gauge after just replacing the o-ring and screw should it?

[madcarlos]

On the other hand it's sometimes enjoyable working on your own guns, I will only attempt a go when I have plenty of time, Its nice if you have a problem and are able to solve it,

[bossmugler]

Just a quick update.

Changed both internal and external o-rings on inlet valve. Swapped pressure relief port bits for custom one.

Reassembled, no air leak and rifle is performing as normal. Enjoyable and simple procedure, which saved me money sending it to Hull Cartridge.

Also those vids on YouTube were invaluable.

Thanks for all your help guys.