Banks Exhaust Brake For Diesel Trucks Towing - 2001 Ford F350 Super Duty Brake Testing

The first test run was done with the brake switched off. We started at the top of the grade, in Third gear, at 58 mph, with John's feet off of the gas and brake pedals. The rig took mere moments to run up to 70 mph, and John had to use the brake pedal to avoid running into other Grapevine traffic. Even when John pulled the gear selector to Second, the truck picked up speed as it rolled downhill. Worse, because the Ford engine controller unlocks the torque converter in Second when no throttle is applied, the transmission fluid heated up rapidly.

For the next run, John flipped the dash-mounted switch that turned on the Banks Brake. Otherwise the parameters were the same: Third gear, 59 mph, and no application of gas or brake. We heard the buzzing of the vacuum pump that powers the brake; and then, when the truck nosed down the grade, came the sound of exhaust flowing by the butterfly valve. The truck held steady at 59 mph at first. Then, slowly, the speed dropped. Halfway down the grade we were at 57 mph-a far cry from the runaway first run. When John downshifted to Second, the Banks Brake held the truck's speed to 35 mph.

A third run tested another Banks product, the SmartLock. This electronic gizmo taps into the engine's computer to lock the torque converter when it would normally unlock under deceleration (which occurs in Second gear in the Ford). By reducing transmission slippage, the SmartLock not only improved the effectiveness of the Banks Brake (our speed in Second was a steady 30 mph), it also lowered the transmission fluid temperature. Where there was a 50-degree differential in fluid temp between the incoming and outgoing sensors during the first two test runs, there was only a 9- to 10-degree difference when the SmartLock was plugged in.

What does all this technology cost? A Banks Brake for the 7.3L Power Stroke runs about $1,200 (less for the Cummins version). The SmartLock costs around $400. Neither is exactly cheap, but both will save wear and tear on your truck's brake and transmission components. Plus, they'll make that next tow to Moab (or the Rubicon, or the Ozarks, or the Smokies) that much more pleasant when you hit one of those long downhill stretches.

10. The pump attaches to the frame with three bolts. One (shown here) goes into an existing hole in the frame; the other two holes need to be drilled.
10. The pump attaches to the frame with three bolts. One (shown here) goes into an existin
11. When the pump is secured to the frame, the exhaust and vacuum lines are pushed onto their fittings. A ground wire is run to the frame, and the pump installation is complete. All it needs now is its power lead from the wiring loom. All wiring is done at the end of the installation process.
11. When the pump is secured to the frame, the exhaust and vacuum lines are pushed onto th
12. The vacuum line from the pump runs to this actuator control valve, which (as its name implies) controls the vacuum signal that actuates the brake. Before the valve can be mounted to the truck, line fittings and a small filter must be attached to the valve body.
12. The vacuum line from the pump runs to this actuator control valve, which (as its name

13. Reassembly begins with the re-installation of the intake plenum. After the plenum is on, the compressor outlet tube is reattached, and the intake tube is remounted.
13. Reassembly begins with the re-installation of the intake plenum. After the plenum is o
14. The MAP sensor is installed back in its original location near the cowl, and the actuator control valve is mounted to the top of the sensor. You can see it just under Dave's thumb.
14. The MAP sensor is installed back in its original location near the cowl, and the actua
15. The vacuum line from the pump is pushed onto its fitting on the actuator control valve, and a second vacuum line is run between the valve and the brake actuator.
15. The vacuum line from the pump is pushed onto its fitting on the actuator control valve

16. When all the hose fittings are in place, it's time to begin the wiring. Here, the power lead attaches to the actuator control valve. As we mentioned in an earlier step, a second power lead is fed down the firewall and out the fenderwell to plug into the vacuum pump.
16. When all the hose fittings are in place, it's time to begin the wiring. Here, the powe
17. The main wiring loom is installed behind a panel under the steering wheel. Luckily the Banks instructions are pretty clear when it comes to what goes where, as making sense of this colored spaghetti would be tough otherwise.
17. The main wiring loom is installed behind a panel under the steering wheel. Luckily the
18. The final step requires a hole to be drilled in the dash to mount the brake switch. Banks provides a template to indicate the hole's location. Once the switch is mounted, follow the instruction booklet's steps to test the system before you hit the road, and you're ready to use the brake.
18. The final step requires a hole to be drilled in the dash to mount the brake switch. Ba

19. The day after the brake was installed, we hit the road with Banks engineers John Sinz (at the wheel) and Troy Larson to see the system in operation. Note the computer sitting between them. It's hooked up to dozens of sensors scattered throughout the truck that give the men readings on everything from ambient temperature to the signal that controls the torque converter lockup.
19. The day after the brake was installed, we hit the road with Banks engineers John Sinz
20. After making several runs up and down the notorious Grapevine section of I-5, we were impressed at the Banks Brake's ability to maintain the rig's speed down the 6-percent grade. This was no lightweight test, either, as the combined weight of the truck and trailer was just shy of the F-350's 20,000-pound GCVW rating.
20. After making several runs up and down the notorious Grapevine section of I-5, we were

What's A Jake Brake?
Big-rig trucks also use engine power to supplement their service brakes, but their engine brakes operate on an entirely different principle than the Banks Brake. Instead of building exhaust backpressure behind the turbo, the jake brake actually changes the engine's exhaust valve timing. In a no-fuel deceleration situation, the jake brake opens the exhaust valves at top-dead-center of what would be the piston's compression stroke. The pent-up energy of the compressed air mass that would have driven the piston down had the valves stayed closed is, instead, vented out through the exhaust. Since no energy is pushing on the crankshaft at that point, the engine's reciprocating assembly slows, which slows down the truck.

So why is it called a jake brake? It's named after the Jacobs Manufacturing Company, which has built the product since the early sixties. Jacobs didn't invent the engine brake, though. It was an idea that came to Clessie L. Cummins (does the name ring a bell?) after he was nearly killed freewheeling down California's Cajon Pass in one of his early diesel trucks. Cummins developed his idea into the first compression-release engine brake in the mid-fifties, but it took Jacobs' investment in Cummins' design to bring the brake to fruition.