engine brake ?
 

is there a way to adjust the oil pressure on a mack to get the engine break to work or should i say adjust the amount of oil it take fro the engine break to work fully it takes 60 psi of oil to make the engine break work to its max after the engine warms up even with lucas and 40 weight the oil pressure is at 50 psi and the engine break putters and sometimes doesnt work at all until it hits 12 psi and then putters so my question is is there a way to get this engine break to work below 60 psi of oil i know that some of our other engine jakes on our macks work at lower oil pressure this is the only one that need 60 psi maybe there something that i can adjust or swap out without getting to deep in the tear down email is sgtmajwrench@ymail.com thanks

My Jake problem is that I turn on the switch and it may or may not work. If it doesn't work, I can help the linkage with my finger, and it comes on, so it seems to me that there is a vaccum problem, or perhaps a diaphragm problem. I checked all the hoses and the solenoid, and it all works well. I don't know how the diaphragm assembly works inside, but the can has a little dent on the outside, that happened during shipment to me. I can't imagine that that would be the issue. When I first installed it, it worked fine. Now, suddenly, it doesn't. Thanks for any ideas...