Page 122
TROUBLESHOOTING
Brake slave piston clearance settings must be
made with the engine stopped and cold and with
the exhaust valves closed.
BRAKE SLAVE PISTON CLEARANCE SETTING
DETERMINING ENGINE OIL PRESSURE AND
OIL PRESSURE AT THE ENGINE BRAKE
UNITS
The engine brake requires a minimum oil
pressure to operate. The oil pressure reading on
the dash gauge is approximately the same as oil
pressure at the engine brake. The exception to
this is pre-2002 engines with Jake™ brake and
without external oil supply lines to the Jake
brakes. On these engines the oil pressure at the
Jake brake is approximately 15 psi less than the
dash gauge.
When determining minimum oil pressure, the oil
temperature must be at least 200°F (93°C) when
the test is performed. The pressure reading from
the dashboard oil pressure gauge is sufficient.
OIL PRESSURE REQUIREMENTS
If the oil pressure remains low, correct the engine
problem as described under “OIL PRESSURE
DROPPING BELOW MINIMUM REQUIRED FOR
ENGINE BRAKE OPERATION” in the
Troubleshooting Guide included in this section.
INSPECTION OF J-TECH™ ENGINE BRAKE
COMPONENTS
If oil pressure at the brake housings is sufficient
for brake operation, then inspect the engine
brake components for excess wear, damage or
malfunctioning conditions described in this
section.
1. Start the engine and allow it to idle for a few
minutes. Check for oil leakage at the oil
supply screw, solenoid valve and housing
pipe plugs. Oil leakage can result in weak,
intermittent or no braking. If leakage is
found, shut down the engine and replace
seals or repair as needed.
When the engine is shut down for several
minutes, the oil in the brake housings will
bleed down. To refill the brake housings for
immediate operation, depress the solenoid
cap (pin) several times to fill the housing
with engine oil.
2. With the engine brake on, observe that the
master pistons are moving out of the
housing and making contact with the
exhaust rocker spherical nuts. They should
move in and out freely. If they do not, shut
down the engine and check the control
valves and control valve springs for those
cylinders.
Remove control valve retaining components
carefully to avoid personal injury. Control
valve retaining components are under load
from the control valve springs.
3. The control valve must move freely in the
bore. If not, remove it and replace with a
new control valve.
If the bore is damaged (scored), use a light
crocus cloth to smooth the bore. Clean the bore
and install a new control valve. If severe damage
to the bore is found, replace the housing.
4. Replace any broken springs.
J-Tech™ Engine Brake
— Adjustment: 0.021 inches (0.533 mm)
— Slave piston adjusting tool: standard feeler gauge
— Adjust following the firing order: 1, 5, 3, 6, 2, 4
J-Tech™ Engine Brake
— Engine rpm 2100: 40 psi (2.8 bar)
— Engine rpm 1700: 35 psi (2.4 bar)*
— Engine rpm 1500: 30 psi (2.0 bar)*
— Engine rpm 1300: 30 psi (2.0 bar)*
— Engine rpm 1100: 30 psi (2.0 bar)*
* Specified pressures with engine at 200°F (93°C)
minimum oil temperature.
5-111.bk Page 122 Monday, July 10, 2006 2:26 PM
To Next Page
Loading...
