could it be that i dont have a check valve. I have a 96 1500 i am replacing vacuum lines up top by the passenger side and i dont see any check valves but i havent got into the cowl yet? tomorrow i am going to replace line by transfer case and i know it shows there is a check valve down there.


Matt

 

id put a check valve before every vaccum accessory, although ive found "Hg to be a bit erratic with these trucks.... whether it be in the check valves or small resevoir, i dont know

 

Just putting one check valve between the engine, and the accesories, should be adequate to the task. There is a vacuum reservoir buried under the cowl somewhere.....