Troubleshooting guide

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Air Brake System Troubleshooting Tests (continued)
CHECKLIST 5
If sluggish performance is noted in either test, check for:
1. Dented or kinked lines
2. Improperly installed hose fi tting
3. A faulty quick release valve or spring brake control valve
4. Damaged or improperly installed Spring Brake Chamber and/or Service Chambers
5. Foundation Brake component binding, improper installation and/or lack of lubrication.
If the trailer brakes do not actuate and the trailer supply line remains charged, check the following:
1. Tractor protection control
2. Trailer spring brake valve
3. Damaged spring brake chamber and/or service chambers
4. Foundation brake component binding, improper installation and/or lack of lubrication
RETEST TO VERIFY PROPER OPERATION OF ALL ITEMS REPAIRED OR REPLACED.
TEST 6
Dual circuit system integrity check (emergency braking) and/or automatic
application of the parking brake and/or Tractor protection valve operation
FULL PRESSURE, ENGINE STOPPED, PARKING BRAKES RELEASED
;
OK
;
Not
OK
1. Drain the front axle or secondary reservoir to 0 psi.
A. The rear axle or primary reservoir should retain most of its pressure.
B. On combination vehicles, the trailer air system should remain charged.
C. Tractor and trailer brakes should not apply automatically.
2. With no air pressure in the front axle reservoir, make a brake application.
A. Rear axle brakes should apply and release when application is released.
B. On combination vehicles the trailer brakes should also apply and release when application is released.
C. The stop lamps should light and go off when the application is released.
3. “Pop” Pressure Vehicle Test Procedure
Note: Bendix is not aware of any federal legislation that specifi es the pressure at which the YELLOW parking brake control valve must
automatically “trip” to apply the vehicle parking brakes. This includes the Federal Motor Carrier Safety Regulations (FMCSR) for in-use
vehicles, the CVSA out-of-service criteria, and the Federal Motor Vehicle Safety Standards (FMVSS) for newly manufactured vehicles.
Although the “trip” pressure for the parking brake control valve is not stipulated for in-use or newly manufactured vehicles, a parking brake
control valve “trip” pressure of 20-40 psi is currently (02/2009) specifi ed as part of the Commercial Driver License in the CDL Manual. The
CDL Manual is not consistent with the regulations cited above. See Bendix Bulletin TCH-003-051.
A. Install an accurate “shop standard” pressure gauge in the secondary service reservoir.
B. Build pressure in the service reservoirs until the compressor cut-out is reached, shut the engine off.
C. Fully open the manual drain valve on the primary service reservoir allowing the reservoir to drain completely.
D. Open the secondary reservoir’s manual drain valve creating a bleed rate of approximately 20-50 psi/min.
E. Monitor the pressure gauge noting the pressure at which the parking control automatically “pops”. This is not a Federal
requirement - See Note in previous column.