The problem with the regs once fooked with is they tend to leak.

They have a hydraulic sealant applied to the threads in production and the tamperproof seal on top is also airtight for a reason. When over zealous mechanics wind it down to teh point it stops, they often nip the internal diaghragm and it becomes unreliable.

If this reg leaks i cannot do the work i need to do on friday without fitment of a new one. Its easy to test for a leak but the engine needs to be running for you to do so. Simply wet your finger and place it over the hole in the top, if you feel a slight "Sucking" on your finger, its FUBAR and needs replacing.