Also, if you have more tubing avail., I would replace both the inlet and outflow tubing to/from the regulator (and maybe even the connectors to straights from 90’s maybe) w/ a little longer tubes as they are pulling the connectors off center which can also lead both (all 3~Reg. in/reg. out/ & block in connectors to leak.
That yellow locking collar on the regulator is half way up, half way down in the pic…Up to adjust regulator pressure, down to lock. Get it into 1 or the other positions also…right side is down/left up in the pic. When it is in the adjustment position it leaks very slightly on purpose to help you adjust the regulator pressure so after adjusting it, always lock it.
Can you attach a few more pictures?
Start at the compressor and work back to the block please. Getting the High Pressure side completed first and holding air (always insert a pressure relief valve in it), dividing the system into sections, and then working towards the low pressure section 2nd. seems to work best when making sure the system doesn’t leak.
Please do not take anything as being critical…Just trying to help. Yes, if it hits 40 PSI and compressor is still running and does not stop running, but does not build pressure, the system is absolutely leaking.
Look very closely at pic #1 and pay strict attention to just the tubes and air connectors…If the tubes are perpendicular to the fittings, and the fitting collars are not highly tilted, their tubes are usually long enough. But, if the tubes are too short, and I see many there in the pic, where the fitting collars are really tilted…Then those particular tubes need to be a bit longer (and or 90’s used in place of straights possibly, or the opposite maybe), to alleviate and stop the chance of air leaks. All pneumatics need to be troubleshot after assembly usually…Once the team gets really expert at it, they can learn to assemble it properly from the very start.
Take the hr. or so now (grab all already cut pcs. of tubing you can find in the shop 1.5" or longer), check every fitting for tightness, flush cut tubing ends, and switch out (always start at the compressor)…The too short pcs. w/ a little longer ones (or change fittings where necessary), and get that system holding pressure firstly (high side/ then low side/ then actuation side). Divide the system into parts (using plugs or tubing loops, and conquer it! If ours has zero to very minimal leakdown when left pressured overnight. Then it is ready to practice or compete with).
I’ll look at the new pics now. TY for providing them.