The Cummins Engine Brake has earned its reputation throughout the trucking industry as being one of the most technically superior
engine braking products available. Designed jointly by heavy duty experts at Cummins and Jacobs, the "C brake by Jacobs" products
have increased the safety of trucking by immeasurable amounts by helping drivers keep control of their 40-ton rigs when hauling
cargo through hilly or mountainous terrain.
However, like any mechanical device, performance of these engine braking systems can deteriorate over time. Engine brake components
wear at the same rate as engine components, reducing the braking horsepower. We recommend tuning up the Engine Brake at the
time of overhead set or engine overhaul. In order to make this maintenance as simple as possible, Tune Up kits are available
for all Cummins engines. These kits come complete with all the parts required for tune up. They are competitively priced with
respect to the competition and customers can save even more if the tune up is combined with another service event like an
overhead set or engine overhaul.
When should a brake Tune-up be carried out?
- During an engine overhead adjustment or an engine overhaul or
- When a driver notices that braking performance has deteriorated
Why do I need to tune up my Engine Brake?
Periodic and regular tune up of your engine brake will maintain the maximum power and performance of your engine brake. It
will avoid unexpected downtime and unscheduled vehicle maintenance and thereby increase productivity by preventing the need
to take a truck out of service for a brake related problem.
How do I select the right Tune Up Kit?
To select the right tune up kit for your engine please see the following table:
| Engine Family |
Engine Brake Model |
Tune-Up Kit |
| Small Cam NH/NT and Big Cam II & III with single entry turbo |
25B/30/30E/400/400H |
3871418 |
| Big Cam with dual entry turbo |
401A/401B/401C |
3871535 |
| Pre 1988 Small Cam & Big Cam NH/NT |
420/425 |
3871536 |
| Small Cam & Big Cam NH/NT |
425A |
3871537 |
| '88NT |
430 |
3871538 |
| L10 |
404/404B |
3871540 |
| N14 |
440/440A, 450A/450B, 445 |
3871568 |
| M11/ISM |
404D/411/411C |
3871580 |
| M11 |
404BG |
3871586 |
| N14 Plus |
455A/455B/455C |
3871704 |
| ISL |
490 |
3800917 |
| Signature/ISX/QSX15 |
Intebrake |
4025010 |
What does the Tune-Up Kit contain?
Typical Tune-up Kit contents include the following*:
- Valve cover and housing gaskets
- Piston cap screws
- Hex head cap screws
- Control valve cover
- Accumulator springs
- Solenoid harness
- Solenoid seal rings
- Control valve springs
- Control valves
- Oil seal rings
- Master piston return springs
- Master piston retainer
- Terminal lead out
- Crosshead pin assembly
*Specific kit contents may vary by model.
Every component is engineered to the latest specs, so that the Engine Brake will work as good as new. Each kit also contains
all of the parts and installation instructions required to restore the brake to peak operating performance.
For more information about Engine Brake Tune-up Kits, please call us toll-free at 1-800-CUMMINS™ (1-800-286-6467), or visit
your local Cummins dealer or distributor.
