hi all just hoping to get some advice on where to go next with my air suspension fault... had an air suspension inactive come up, had it plugged in, 'air accumulator static when filling' ive taken the compresssor apart and replaced the piston ring, also i took the dry air filter apart to clean the cloth filters and try and sift any dirt out the pellets ect.. after rebuilding it all had it plugged back in and has reached 8.5 barin the accumulator then the pump cuts out (over heat/timed out). ive ordered a straight connector to replace the release valve in the tyre space. (im trying to figure out a way to externally test if that is failing at 8.5 bar) im also wondering if anyone has any advice on how i could test the pressure the pump is producing externally? as that could rule out the cars pressure sensor failing, if anyone could offer any knowledge advice or tips id be massively greatful, as plugging in between 'trial repairs' is getting costly, many thanks jamie

This sounds similar to a problem I had when I replaced the piston ring in my compressor. The accumulator would not get to the correct pressure of around 187PSI (about 12-13 Bar). Put the original piston ring back in and all was well (ran straight up to 187 PSI).
It's possible that either your new piston ring isn't sealing properly, the bore is damaged / scored, or you may have put the new piston ring on in the wrong orientation (if that's possible, sure someone will be along to verify or refute if that's possible).

after some messing around and testing, i took the compressor to my local compressor service company to get it pressure tested (to eliminate a accumulator sensor failing.. the compressor was running 8.6 bar again, i took apart and like u said took the newly fitted ring off to visually check for defults ect put back together, after testing again 14 bar! perfect! .. i asked to have the pressure safety release valve checked for leaks, and it was failing to keep pressure above 8.6 bar so we replaced with a T to join the 6mm from compressor to 8mm to the tank, plus i added a pressure gauge of the T as well to visually see the current tank pressure, after plugging back in to erase fault and reboot the system the suspension ran better than ever! hits 11.3bar shuts off car raises and lowers to correct heights with no hesitation

i am always happy to offer advice or ask questions on any of the steps ive done to repair my 'suspension inactive' / 'air accumulator static when filling'

So your actual problem (after fixing the compressor ) was the reservoir PRV or the PRV by the compressor? .
Experience is the only genuine knowledge, but as time passes, I have forgotten more than I can remember
Volvo V70 P2 2006 2.4 Petrol 170bhp Estate SE
MG Midget Mk1 1962

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replacing the piston ring and replacing dry air filter contents is must regardless of weather your getting faults as it will massivly increase your compressor performance/life and the alternator life as well!, since servicing the pump the pressure builds to 11.3 bar in 30 seconds (pump gets no hotter than 65 degrees, as before it was taking couple minutes and the pump was timing out/overheating to 105 degrees) however this wasnt putting the car into fault mode, it was only when the PRV in the boot straight off the compressor failed and vented air that we had the problems, i will upload pictures of my repair later today, for people to use hopefully to repair there air issues, all in all the repairs cost me less than 30 quid, where as a replacement pump is alot more!