This was the 3rd stage of the kit that was serviced.
There are two more stages that reduce the pressure from upto 200 bar down to atmospheric pressure. Those stages should be serviced if having the right tools, otherwise calibration will be affected and you may not achieve the same ever again.
Even at this stage 3, take care no to bend the lever inside, take care not to damage the diaphragm or bend its center metallic portion, inspect the diaphragm for any leakages/ holes/ tears, it should be absolutely perfect and should seal the inner chamber in an airtight manner.