HW 100 leak experts - please.

[essjay]

I’d appreciate a little advice please.
My HW100’s had a slow leak for ages – I’ve replaced all the o-rings at least twice. Today, I submerged the pressurised components and found the points where air was leaking. The main place is the vent port on the underside of the action – I assume this means the o-ring seal on the inlet valve is defective and needs replacing – again.
There was also a smaller leak from around the regulator pressure adjuster screw – seems that the o-ring on the piston is leaking too.

This is a diagram of the arrangement, but my rifle is a bit different and I wonder if this is a design change or I’ve something missing
I don’t have part 2671 described as a Disk, nor part 2672 o-ring.
The pressure regulator screw on my rifle is a plain screw with no facility to fit an o-ring.
What does the disk & o-ring do?
Any thoughts?
Thanks.

[Mitchellman]

Get your self some leak detection spray, it will give you a better indication of where its coming from, avaliable from all good plumbing merchants.

Kind Regards

Mitchellman

[Elliott]

You need POK!'s help, he's the HW100 man - if you're a member of the WOC he posted some HW100 tweaks on there. Give him a shout out on here too, he's a regular vistor.

Hope you get it sorted, its a great rifle!

[POK!]

I don’t have part 2671 described as a Disk, nor part 2672 o-ring.
The pressure regulator screw on my rifle is a plain screw with no facility to fit an o-ring.
What does the disk & o-ring do?
Any thoughts?
Thanks.

HW100 has been upgraded several times, it's hard to keep up with the changes. The parts described above have been omitted for some time now and the washer stack is vented via the rear stock fixing hole anyway. Sounds like you need to replace o-rings on reg piston and main valve.

The inlet o-ring wears quickly so you should always have a good supply of these or you can try and source them in Polyurethane i.e "BS 005 PUR 70" The reg piston o-ring will eventually take a compression set and become slightly square in section, this o-ring rolls as the piston moves and should be lubricated with a pure silicon grease.

[Charlts]

Pok! Just a thanks for taking the time to list all the o-ring sizes, it's helped me a lot this past week.

[essjay]

HW100 has been upgraded several times, it's hard to keep up with the changes. The parts described above have been omitted for some time now and the washer stack is vented via the rear stock fixing hole anyway. Sounds like you need to replace o-rings on reg piston and main valve.

The inlet o-ring wears quickly so you should always have a good supply of these or you can try and source them in Polyurethane i.e "BS 005 PUR 70" The reg piston o-ring will eventually take a compression set and become slightly square in section, this o-ring rolls as the piston moves and should be lubricated with a pure silicon grease.

Many thanks POK,
I'll order some new o-rings and do it all again.
Can't find a source of PU in the UK so will stick with Nitrile and some silicon grease.
Regards
sj