This is a good question that I've yet to get an answer on myself. I work in a factory that builds John Deere Harvesting equipment, and even the coffee machine has torque specs to it, that is how utterly thorough Deere is. The pump manufacturers HAD to have some specification on this given the frailty of the glass cylinders. I just snug mine down very gently in a criss cross pattern like when you put heads on an automobile engine. So far I've had good luck, but there has to be a better way. If I ever find it I'll post it here.....
