I have to say I'm pleased with the retract units and included air system, besides swapping out the filler valves to Robart valves (to standardize and fit my compressor), and installing SMC pressure gauges I've used all the included stuff and the retract system is 100% leak proof, it's been holding 50psi for something like 3 weeks now. The brakes bleed out pressure ever so slowly over a few days, but that's ok too.