HW100 Cylinder Service

[Blackmax]

Unable to remove the brass insert out of the O ring for replacing on Fenton's valve, as the "O ring" is completely close on one side around the insert (see image named "washer detail" in my prevous post). Moreover I'm quite reluctant to force the brass insert for removing from the valve, as it will risk to break the valve pin - not sure why it has been built this way.

Carefully cut the O ring with a Stanley knife without damaging the brass insert then.

 

[Paolo3000]

Carefully cut the O ring with a Stanley knife without damaging the brass insert then.

Done. Removed the worn "o ring" and replaced with a brand new one. Impossible to determine the original dimensions of the old o ring, replaced with an "hw original" one - hopefully it will work. I will start by inflating around 100 bar to verify if the valve is working properly, then I will increase the pressure. Thanks for your help.

 

[hillrx8]

With the cylinder secured as previously described, it’s now time to take off the outlet end. As I said before, leaks on this end seem to be rare and out of the fifty or so cylinder services I’ve done under five have been this end, with two being due to people fiddling.

You’ll need a specialist tool to take this end off, theses are available from HW100 Tuning or Fentons.

Again, sometimes theses can be tight so make sure the cylinder is secure.

View attachment 496302

Use a suitable spanner on the tool and remove the end. Once inside you’ll see the valve access screw, it’s the same process as above to remove it, ensuring you have an appropriate screwdriver. This is a Fentons cylinder end I believe and they’re generally not done up as tight as the factory ones.

View attachment 496306

As with the filler valve, ensure you clean the parts thoroughly after you’ve removed the old O rings. The O ring sizes are the same.

It’s the same process for reassembly, with one important point - TEST THE VALVE prior to putting the cylinder end back on and pressurising it. The valve is straightforward and is designed to work with the inlet/regulator assembly, however you need to make sure the parts are lined up and that the piston goes in and out! To test it use a fiat ended implement such as a delrin rod or suitable parallel punch, push the valve piston in and out. If it doesn’t move then you haven’t reassembled it correctly, so do it again.

View attachment 496311


Weihrauch recommend that cylinders are only serviced by approved service agents.

Once you have tested the valve you can reassemble, again the cylinder end only needs to be hand tight.

I may have missed some bits so feel free to ask questions..

BM

You push the brass in as the valve goes up and down or all the way???

 

[Lockdown Leatherworks]

Incredibly useful for the newbie owner of a very well used HW100 KT

Thanks

 

[NEJ]

Thanks this was really informative

 

[Steve350]

Great tip for us newbies thanks

 

[Philthunder]

I use a 6 sided hex 36mm on the ends with insulation tape wrap, not damaged them yet and for taking the valve housing off. The back of a machine hacksaw blade works well, if you don’t have a suitable screwdriver

 

[Clothead]

With the cylinder secured as previously described, it’s now time to take off the outlet end. As I said before, leaks on this end seem to be rare and out of the fifty or so cylinder services I’ve done under five have been this end, with two being due to people fiddling.

You’ll need a specialist tool to take this end off, theses are available from HW100 Tuning or Fentons.

Again, sometimes theses can be tight so make sure the cylinder is secure.

View attachment 496302

Use a suitable spanner on the tool and remove the end. Once inside you’ll see the valve access screw, it’s the same process as above to remove it, ensuring you have an appropriate screwdriver. This is a Fentons cylinder end I believe and they’re generally not done up as tight as the factory ones.

View attachment 496306

As with the filler valve, ensure you clean the parts thoroughly after you’ve removed the old O rings. The O ring sizes are the same.

It’s the same process for reassembly, with one important point - TEST THE VALVE prior to putting the cylinder end back on and pressurising it. The valve is straightforward and is designed to work with the inlet/regulator assembly, however you need to make sure the parts are lined up and that the piston goes in and out! To test it use a fiat ended implement such as a delrin rod or suitable parallel punch, push the valve piston in and out. If it doesn’t move then you haven’t reassembled it correctly, so do it again.

View attachment 496311


Weihrauch recommend that cylinders are only serviced by approved service agents.

Once you have tested the valve you can reassemble, again the cylinder end only needs to be hand tight.

I may have missed some bits so feel free to ask questions..

BM

Fantastic showing how to do this service very helpful , Im just lucky that Steve at HW100 is just down the road from me and my shooting partners mate

 

[Philthunder]

Fantastic showing how to do this service very helpful , Im just lucky that Steve at HW100 is just down the road from me and my shooting partners mate

No excuses then, for not having the best HW100 around

 

[Alfieargyle]

Thanks very much for creating this guide. I need to look at mine in the coming weeks as I can hear a small leak once I get around 150bar+ so currently only charge the rifle up to 150bar.

 

[Clothead]

If you’re near to HW100 Tunning Steve’s you man

 

[Glam69]

From experience the cylinder ends mark easily. Even using the adapter on the outlet end marks the part.

Most have marks from the fill probe and you'd be surprised how resilient the fill hole is.

Even the gunsmiths use a disclaimer about marks on the cylinder after repair, therefore you have to be extremely careful.

 

[Glam69]

For information…….
Generally seal kits available on a well known auction site do not contain the o rings to service the Weihrauch air cylinders, they are listed and are available separately though.

 

[Glam69]

Just serviced my leaking HW100TH cylinder, best fiver ( thanks to flea bay) and 1hour of my time I’ve ever spent.
Can resume my shooting now.
Thanks for the comprehensive guide.