Exhaust Brake?
Got a Jakob's on mine. Replaces the cast elbow on the back of the turbo. It's a Cummins/Dodge part, so it integrates into the truck's ECM. Has an on/off switch (mounted to the shifter on my 6-speed). When on, the computer applies the brake when accelerator position is at 0% for 2 seconds. The delay is to allow a manual trans to be shifted without the brake coming on between gears. This delay may not be present on an automatic trans truck, I don't know.
The brake is powered by a vacuum pump that mounts to the cylinder head with 3 bolts directly above the CP3 and is driven by the serpentine belt. When activated, the computer sends a signal that actuates a vacuum solenoid which actuates a vacuum cylinder on the side of the brake. This cylinder closes a large butterfly valve inside the brake housing which holds the exhaust pressure inside the engine on the exhaust stroke.
I installed mine myself in the driveway. Took about 5 hours, but think I could shave an hour off that time now that I've done one.
I've heard reports of the vacuum pumps having reliability issues. I can't confirm this as mine lasted 94,000 miles before giving up the ghost. I've also heard the vacuum style exhaust brakes aren't supposed to do well in higher elevations. I call B.S. as mine would hold my truck and 8,000 lb 5th wheel camper at 35mph on a 7% grade with the trans in 4th gear, while never touching the wheel brakes, for as long as I wanted it to while on our trips to the Rockies.
Best part of my Jake is, even with all the traveling and towing, I now have 95,000 miles on my truck and I'm STILL on the original brakes! How many people out there can say that?
The brake is powered by a vacuum pump that mounts to the cylinder head with 3 bolts directly above the CP3 and is driven by the serpentine belt. When activated, the computer sends a signal that actuates a vacuum solenoid which actuates a vacuum cylinder on the side of the brake. This cylinder closes a large butterfly valve inside the brake housing which holds the exhaust pressure inside the engine on the exhaust stroke.
I installed mine myself in the driveway. Took about 5 hours, but think I could shave an hour off that time now that I've done one.
I've heard reports of the vacuum pumps having reliability issues. I can't confirm this as mine lasted 94,000 miles before giving up the ghost. I've also heard the vacuum style exhaust brakes aren't supposed to do well in higher elevations. I call B.S. as mine would hold my truck and 8,000 lb 5th wheel camper at 35mph on a 7% grade with the trans in 4th gear, while never touching the wheel brakes, for as long as I wanted it to while on our trips to the Rockies.
Best part of my Jake is, even with all the traveling and towing, I now have 95,000 miles on my truck and I'm STILL on the original brakes! How many people out there can say that?
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