Hi there, I work in heavy machinery rebuilding and we were reviewing a leak test procedure to make it standardized. Essentially, the brake piston squeezes together the clutch plates (stationary) and the friction disks (which move with the shaft). The piston is pushed by compressed springs between the piston and the housing. Brake fluid pushes from the other side in a sealed chamber at about 600 psi to disengage the brakes, and it is depressurized when the brakes need to be used. The status quo for testing is to fill the brake fluid chamber to the standard operating pressure (about 600 psi) and attach a dial pressure gauge on one end while closing a valve on the other side. The gauge is observed for a minute or two and if there is any drop in pressure larger than about 15 psi it is determined to be a problem. I feel like there needs to be a safety factor in the test, but the technicians think that it will damage the seals. They've observed that after a certain pressure (around 800psi) the seals just blow out of the chamber. Does anybody have any ideas/insight they could bring? The procedure has been an on-again off-again job among the engineers here for years. Also, if you could bring some solid evidence to the table, that would be preferred to industry anecdotes (although anecdotes are helpful too!) Thanks!