S410 manometer

[woody2906]

Some weeks ago the dog leg on the gauge developed a leak at the base so bought a seal kit and renewed the dog leg one. On filling the gun the gauge very slowly and eventually settled on 190 ish where it stayed after a several shots ( the gun is a classic FAC and gives about 30 shots from 190 down to 100 so uses a lot of air) after 20 shots it went down in one step to 150 where it seemed to get stuck.

I noticed that when I renewed the o ring at the base of the dog leg it was a fairly snug fit to the shaft of the allen head bolt, pressumabley the gauge works by air flowing around the bolt and up into the gauge itself?
I was just about to order a new gauge when I thought maybe the o ring is squashed against the shaft and obstructing the passage of air into the gauge so I have slackened it off a touch and hey presto the gauge seems to be working again and is not leaking.

Has anyone else had issues with the gauge in this way, from other posts on the Forum I know they can be a source of leaks and problems?

[Roger5]

I might be wrong, but I think you might have used wrong o ring, the one you should use is S427 you may have used S536 by mistake. Rog

[Blackbaronfish]

It has been known before . Sometimes you can back it of a little to get it to work.

BBF

[TenMetrePeter]

I had a gauge stuck on 150 from new. Mine goes straight into the cylinder end, not a dogleg, and if yours moved again on twiddling it is probably not the same problem.

[woody2906]

I had a gauge stuck on 150 from new. Mine goes straight into the cylinder end, not a dogleg, and if yours moved again on twiddling it is probably not the same problem.

I remember you had that from new! and had to buy a thin walled spanner to fit it. The o ring I used was the one for the purpose in the kit, it's the same one as that for the transfer port I believe.

Thanks to those who responded confirming that the o ring can pinch off the airflow