Persistant HW 100 leak

[Artfull-Bodger]

There can be a tolerance issue on the inlet valve, you sometimes have to try a BS005 alternative to get it to seal reliably, I recently had one in that would not seal no matter what ring was used, in the end I changed the inlet valve and that cured the problem.

I suppose if your air cylinder inlet bore is close to max tolerance and your inlet valve spigot close to bottom you could get a stubborn leak, after all they are made to production tolerances not absolute precision.

HW100 Tuning is a good supplier however, all the rings I have bought off him have been correct to model and size.

[Benelli B76]

There can be a tolerance issue on the inlet valve, you sometimes have to try a BS005 alternative to get it to seal reliably, I recently had one in that would not seal no matter what ring was used, in the end I changed the inlet valve and that cured the problem.

I suppose if your air cylinder inlet bore is close to max tolerance and your inlet valve spigot close to bottom you could get a stubborn leak, after all they are made to production tolerances not absolute precision.

HW100 Tuning is a good supplier however, all the rings I have bought off him have been correct to model and size.

I service 5 or 6 rifles a week and never had this problem before with the 100 which I find is one of the simplest rifles to work on. What you say makes sense. Fortunately I have a huge collection of O rings in various materials. The polyurethane one that worked was a tight fit on the valve and of a very high Shore hardness, almost like nylon, and sealed well.

Baz

[Artfull-Bodger]

I service 5 or 6 rifles a week and never had this problem before with the 100 which I find is one of the simplest rifles to work on. What you say makes sense. Fortunately I have a huge collection of O rings in various materials. The polyurethane one that worked was a tight fit on the valve and of a very high Shore hardness, almost like nylon, and sealed well.

Baz

Yes it is rare that you just cant get one to seal, I have only seen two and only one had to change the valve, and like you I service these regularly.

What's bizarre is the o-ring works by deflecting under pressure and basically jamming itself into the gap causing a seal, so a softer one should work better as it's not a gasket, but sometimes the poly ones do work where rubber fails, I can only conclude it's a tolerance thing?