Troubleshooting guide

For more information, visit www.bendix.com or www.foundationbrakes.com • 1-800-AIR-BRAKE (1-800-247-2725)

FULL PRESSURE, TRACTOR PARKING BRAKES APPLIED

(YELLOW BUTTON OUT) & TRAILER CHARGED (RED BUTTON IN)

;

Not

1. Allow the air pressure to stabilize for at least 1 minute.

Observe the dash gauge pressures for 2 minutes and note any pressure drop.

A. Pressure Drop: Single Vehicle (A 4 psi drop within 2 minutes is allowable for either service reservoir)

B. Pressure Drop: Tractor/Trailer (A 6 psi drop within 2 minutes is allowable for either service reservoir)

C. Pressure Drop: Tractor/2 Trailers (An 8 psi drop within 2 minutes is allowable for either service reservoir)

MAKE ALL NECESSARY REPAIRS BEFORE PROCEEDING TO TEST 3;

SEE CHECKLIST 2 FOR COMMON CORRECTIONS.

CHECKLIST 2

If there is excessive leakage in the supply side of the pneumatic system, one or more of the following devices could be causing the

problem:

NOTE: A leak detector or soap solution will aid in locating the faulty component.

1. Supply lines and ﬁ ttings

2. Low pressure indicator(s)

3. Service brake relay valve(s)

4. Spring brake relay valve (where applicable)

5. Dual brake valve

6. Trailer hand control valve

7. Parking control valve

8. System safety valve(s) in the supply reservoir and/or air dryer

9. Governor (may be mounted on the air dryer as illustrated, on the compressor, or remotely)

10. Compressor discharge line

RETEST TO VERIFY PROPER OPERATION OF ALL ITEMS REPAIRED OR REPLACED.

Air Brake System Troubleshooting Tests (continued)

Bendix

MV-3

valve

Leakage (reservoir air supply)

For additional information, refer to video Assessing Air Brake

System Air Leakage (BW2327 - CD)

TEST 2