Free ASE Transit Bus Brakes (H4) Examination Practice Questions

Sample Practice Questions

Try these 10 sample questions from the ASE Transit Bus Brakes (H4) Examination practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1During a static air-loss test, why must the engine be stopped after the system reaches full pressure?

   1. A. To prevent compressor output from masking air loss
   2. B. To vent the service chambers through the foot valve
   3. C. To make the governor increase reservoir pressure
   4. D. To apply air pressure to the spring brake release ports

   Answer: A

   Explanation: The procedure specifies "Full pressure, engine stopped, parking brake applied". Stopping the engine removes replenishment by the engine-driven compressor, allowing pressure decay to reveal leakage.

   Reference: Prevost Maintenance Manual — Section 12: Brake and Air System — p.22, Air Supply Reservoir Leakage

2. 2A bus has Type 30 chambers on both ends of an axle, but one slack-adjuster arm is 5.5 inches and the other is 6 inches. What imbalance should be corrected?

   1. A. Unequal chamber-area times lever-length factors
   2. B. Equal leverage factors because both chamber areas match
   3. C. Equal leverage factors because both arms operate cam brakes
   4. D. Unequal chamber areas caused by the different lever lengths

   Answer: A

   Explanation: Meritor defines "AL factor" as chamber area times slack-adjuster length and requires equality across the axle. With equal chamber area, different arm lengths produce different leverage factors.

   Reference: Meritor Maintenance Manual 4 — Cam Brakes and Automatic Slack Adjusters — p.52, Before You Return the Vehicle to Service, item 8

3. 3An MGM tamper-resistant spring brake chamber has an internal failure. What service action is permitted by EB 24-001?

   1. A. Open the sealed power-spring housing on the bench
   2. B. Replace the failed chamber or actuator as instructed
   3. C. Cut away the retaining ring before caging the spring
   4. D. Remove the spring head to inspect the power spring

   Answer: B

   Explanation: The spring chamber has "no user-serviceable parts". Its high-energy spring makes unauthorized disassembly hazardous; the prescribed remedy is assembly replacement.

   Reference: MGM Brakes S-Cam Drum and Disc Actuator Service Manual — p.1, spring chamber warning

4. 4Why does PA1561 require marking a wheel's position before removing it from the axle?

   1. A. To establish wheel-bearing preload from the wheel's angular position
   2. B. To preserve the previous wheel-to-hub balance arrangement
   3. C. To establish wheel-nut clamping torque from the wheel's angular position
   4. D. To substitute the wheel's angular position for a runout measurement

   Answer: B

   Explanation: The manual requires marking position to avoid "a new wheel balancing". Reinstallation preserves the previous wheel-to-hub arrangement.

   Reference: Prevost Maintenance Manual — Section 13: Wheels, Hubs and Tires — pp.4 and 8, Wheel removal cautions

5. 5Reservoir pressure holds with the service brakes released but falls rapidly while they are held applied. Which test most directly locates the application-dependent leak?

   1. A. Soap-test the compressor inlet with the pedal released
   2. B. Soap-test service connections and components with the pedal applied
   3. C. Check the dryer cartridge with all reservoirs drained
   4. D. Check the governor mounting with the parking brakes applied

   Answer: B

   Explanation: The service-side leakage procedure requires the "foot brake applied" while coating connections and pneumatic components with soap solution. This pressurizes the circuit that leaks only during application.

   Reference: Prevost Maintenance Manual — Section 12: Brake and Air System — pp.22–23, Excessive leakage on brake service side

6. 6A cam brake drags after the parking control is released. Pressure at its spring-release port is low, and restoring specified hold-off pressure releases the brake. Which fault fits these findings?

   1. A. Excessive clevis-pin bushing clearance
   2. B. Insufficient spring-brake hold-off pressure
   3. C. An undersize camshaft bushing journal
   4. D. An oversized brake-drum friction bore

   Answer: B

   Explanation: MM4 lists "Insufficient air system pressure" as a cause of drag because the parking spring applies. Restoring the specified hold-off pressure removes that spring load in this case.

   Reference: Meritor Maintenance Manual 4 — Cam Brakes and Automatic Slack Adjusters — p.55, Diagnostics, linings drag — insufficient air system pressure

7. 7What mounting-nut torque range does MGM EB 24-001 specify during inspection of its brake actuator assembly?

   1. A. 50–60 lb-ft
   2. B. 85–100 lb-ft
   3. C. 133–155 lb-ft
   4. D. 180–210 lb-ft

   Answer: C

   Explanation: The inspection specifies "133-155 ft-lbs". The 180–210 figure is in Nm, not lb-ft.

   Reference: MGM Brakes S-Cam Drum and Disc Actuator Service Manual — p.10, §2.1 Visual Inspection Points, Mounting Hardware

8. 8What support does Meritor MM23E specify while placing the planetary wheel hub and ring-gear hub assembly onto the spindle?

   1. A. Let the unsupported outer bearing carry the complete hub weight
   2. B. Draw the unsupported hub onto the spindle with its bearing nut
   3. C. Keep the hub assembly supported with a suitable lifting device
   4. D. Draw the unsupported hub into position with axle-flange fasteners

   Answer: C

   Explanation: The hub installation uses a "lifting device" and keeps the hub supported while the ring-gear assembly is positioned.

   Reference: Meritor Maintenance Manual 23E — Bus and Coach Planetary Drive Axles — p.18, Hub and Ring Gear Assembly, step 3

9. 9A bus has slow brake application and slow release. A service air tube is visibly dented. Which fault best explains both delays?

   1. A. A relay-valve inlet stuck fully open
   2. B. A foot-valve exhaust stuck open
   3. C. A partial restriction in the air tube
   4. D. A chamber-exhaust valve stuck closed

   Answer: C

   Explanation: The manual associates "slow brake application or slow brake release" with a restricted line and identifies dents or kinks as causes of partial restriction. The dented tube can delay airflow in both directions.

   Reference: Prevost Maintenance Manual — Section 12: Brake and Air System — p.8, §8.4 Air Line Operating Test

10. 10A Meritor cam brake squeals and has glazing over 15% of the friction surface, without other defects. Which corrective procedure is listed for this degree of glazing?

    1. A. Replace all linings as the chart's required treatment for this glaze amount
    2. B. Solvent-clean the friction faces and omit any conditioning procedure
    3. C. Perform the brake burnish procedure specified for limited glazing
    4. D. Hand-sand only the visible glazed areas instead of burnishing

    Answer: C

    Explanation: For glazing at 20% or less, the chart specifies the "Brake Burnish procedure". The stated 15% lies within that condition.

    Reference: Meritor Maintenance Manual 4 — Cam Brakes and Automatic Slack Adjusters — p.57, Diagnostics, lining glazing 20% or less