Hi Slaw
maybe this helps maybe not.
Anyway - I have a Campbell Hausfeld compressor that I use with some air tools.
Last winter it experienced the same symptom you described from the tube going from the tank to the pressure gauge.
In my case it was the brass insert and delrin sleeve had worn out.
Not until it was to max pressure did it start expelling the air.
I brought the worn brass sleeve to home depot and I picked up a new one.
The lip on the brass sleeve had worn out down to almost nothing. this fixed the problem for a couple dollars.
good luck with yours. there are a couple guys with Jun-Air's here hopefully they chime in.
maybe this helps maybe not.
Anyway - I have a Campbell Hausfeld compressor that I use with some air tools.
Last winter it experienced the same symptom you described from the tube going from the tank to the pressure gauge.
In my case it was the brass insert and delrin sleeve had worn out.
Not until it was to max pressure did it start expelling the air.
I brought the worn brass sleeve to home depot and I picked up a new one.
The lip on the brass sleeve had worn out down to almost nothing. this fixed the problem for a couple dollars.
good luck with yours. there are a couple guys with Jun-Air's here hopefully they chime in.