Beto track pump, non return valve location.

[gbb]

My old trusty track pump, a Beto with a metal cylinder has now stopped inflating tyres, or rather it does but then the air escapes instantly., I havnt narrowed down where it's escaping from yet.

I see you can buy a new hose and head quite cheap...but is there a non return valve in the head...or is it in the body of the pump itself ?

Anyone had similar ? Did a new hose fix it ?
TIA.