The 2003 thru 2007 Dodge/Cummins Turbo Diesel Jacobs exhaust brake is a belt driven pump with a dry sealed bearing behind the pulley and two internal roller bearings in the rear cavity supplied by its own small pre-filled oil reservoir with an internal shaft oil seal.
When the pump has reached the end of its service life it usually becomes audible and the oil from inside the pump begins to appear on the top of the pump. The oil is usually black in color.
The shaft inside the pump has a small cam pressed on to it that activates the diaphragm piston. This is built into a roller bearing that is lubricated by the oil in the pump.
The replacement Gould Jacobs Exhaust Brake comes with an original design steel pulley that turns at a slightly lower RMP range having no effect on the jake brake operation, but extends the life of the pump. The pump is ready to bolt on and go with the existing belt.
GOULD Replacement Vacuum Pump for the Jacobs Exhaust Brake ('03-'07, 5.9L) WITH PULLEY