mine had a lot of oil in the lines ect the po changed the compressor but like everything he and the mechanics he had working on the bus did a half as## job and did not blow the lines out. when i changed the front brake chambers a big puddle of oil came out of each side. the only problem i can see is if the oil started deteriorating the rubber parts on the inside. i suppose since the oil in the lines doesnt get real hot that could be a plus.