Free Red Seal Transport Trailer Technician Examination Practice Questions

Sample Practice Questions

Try these 10 sample questions from the Red Seal Transport Trailer Technician Examination practice bank. Each includes the answer and explanation. Continue with the interactive practice above to review the full question set.

1. 1A transport trailer technician checks the WHMIS label on a cylinder classified as a compressed gas. Which pictogram identifies the pressure hazard?

   1. A.Flame over circle
   2. B.Gas cylinderCorrect answer: B
   3. C.Corrosion
   4. D.Exploding bomb

   Explanation: CCOHS lists the "gas cylinder pictogram" for "Gases under pressure (Compressed gas, Liquefied gas, Refrigerated liquefied gas, and Dissolved gas)". The other pictograms identify oxidizing, corrosive, or self-reactive and organic peroxide hazards rather than the gas-under-pressure class.

   Reference: CCOHS WHMIS - Pictograms — What pictograms are used with WHMIS hazard classes and categories? Gas Cylinder

2. 2A technician is diagnosing an air-suspended trailer whose ride height changes with load. Which valve regulates air flow to the suspension springs to maintain ride height?

   1. A.Pressure protection valve
   2. B.Height control valveCorrect answer: B
   3. C.Quick release valve
   4. D.Brake relay valve

   Explanation: Hendrickson states that "Height control valves manage air flow to the suspension's air springs to maintain consistent ride height." This identifies the valve that controls spring air for height regulation.

   Reference: Hendrickson Trailer Height Control Valve — Trailer Height Control Valve

3. 3During a British Columbia trailer inspection, a technician measures the rod stroke of an air brake chamber from fully released to fully applied, with the engine off and reservoir pressure at 95 psig. The chamber manufacturer's maximum available stroke is 2.50 inches. Under the provincial standard, what is the maximum permitted rod stroke?

   1. A.1.25 inches
   2. B.2.00 inchesCorrect answer: B
   3. C.2.50 inches
   4. D.3.125 inches

   Explanation: The standard says the rod stroke "must not exceed 80% of the chamber manufacturer's specified maximum available stroke" under the stated test conditions. Here, 2.50 × 0.80 = 2.00 inches. Applying 50% gives 1.25 inches; omitting the reduction gives 2.50 inches; dividing by 0.80 gives 3.125 inches.

   Reference: British Columbia Motor Vehicle Act Regulations — Division 7, Schedule — Standards for the Approval of a Motor Vehicle, item 24, Pedal reserve

4. 4A trailer technician checks bearing end play by measuring axial movement of the wheel end relative to its spindle. Which instrument is specified for this measurement in the Red Seal occupational standard?

   1. A.Outside micrometer
   2. B.Vernier caliper
   3. C.Dial indicatorCorrect answer: C
   4. D.Depth micrometer

   Explanation: The occupational standard specifies that "bearing end play is measured using dial indicator". An outside micrometer, vernier caliper or depth micrometer measures dimensions directly; the specified instrument tracks relative movement along the spindle axis.

   Reference: Red Seal Occupational Standard – Transport Trailer Technician — page 88, sub-task D-10.02, performance criterion D-10.02.02P

5. 5A trailer kingpin originally measures 2.000 inches at its nominally 2-inch bearing diameter. An inspection guide calls for replacement at 1/8 inch of diameter wear. Assuming uniform wear, what diameter corresponds to that wear?

   1. A.1.7500 inches
   2. B.1.8750 inchesCorrect answer: B
   3. C.1.9375 inches
   4. D.2.1250 inches

   Explanation: The inspection bulletin says "Wear of 1/8˝ (.13˝) is indicated" by its appropriate gauge slot and directs replacement when the slot fits. Converting 1/8 inch to 0.125 inch and subtracting it from 2.000 inches gives 1.875 inches. Subtracting twice the wear gives 1.7500, subtracting half gives 1.9375, and adding it gives 2.1250 inches.

   Reference: SAF-HOLLAND Kingpin Maintenance and Replacement Recommendations — Kingpin Maintenance, item 4, Inspect the Kingpin for Wear, page 1

6. 6A trailer lamp is dim while switched on. A technician wants to measure the voltage drop in the lamp's ground return. Between which points should the voltmeter be connected?

   1. A.The lamp ground terminal and battery negativeCorrect answer: A
   2. B.The lamp supply terminal and battery positive
   3. C.The lamp supply terminal and lamp ground terminal
   4. D.The battery positive terminal and battery negative

   Explanation: Fluke describes measuring "the voltage loss from the ground side of the load to the battery" and says current must flow for a voltage-drop test. The first pair spans the lamp ground return; the other pairs span the supply side, the lamp itself or the battery.

   Reference: Fluke Diagnosing Voltage Drops: Electrical Automotive Troubleshooting — Voltage Drop Tests, diagram caption on voltage loss between battery and load

7. 7A trailer hydraulic cylinder drifts under load. During a controlled internal-leakage test, the technician pressurizes one side of the piston and observes fluid at the opposite cylinder port. Which fault is this test intended to identify?

   1. A.Leakage past the piston sealCorrect answer: A
   2. B.Leakage past the rod seal
   3. C.Leakage at the cylinder body seal
   4. D.Leakage at the hose fitting seal

   Explanation: Parker describes checking a suspected piston-seal leak by having "one side of the cylinder piston be pressurized and the fluid line at the opposite port be disconnected" and observing the leakage. The other seals are potential external leakage locations rather than the piston bypass being tested.

   Reference: Parker Industrial and Pneumatic Cylinder Operating Instructions and Maintenance Manual — Section 4.2.2.3, Internal Leakage

8. 8A trailer refrigeration unit shuts down when compressor discharge pressure becomes excessive. Which protective device opens the unit's run circuit in response to that pressure?

   1. A.High-pressure cutout switchCorrect answer: A
   2. B.High-pressure relief valve
   3. C.Low-oil-pressure switch
   4. D.Low-oil-level switch

   Explanation: The manual identifies the high-pressure cutout switch on the compressor discharge manifold and states that when pressure becomes excessive, "the switch opens the circuit to the run relay to stop the unit." The relief valve releases refrigerant pressure; the oil switches respond to oil conditions.

   Reference: Thermo King SLXi Trailer Unit Operator's Manual — Unit Description, Unit Protection Devices, pages 28–29

9. 9A technician needs the product-specific first-aid measures after an eye exposure to a trailer-cleaning chemical. Which section of its WHMIS safety data sheet should the technician consult?

   1. A.Section 6
   2. B.Section 8
   3. C.Section 4Correct answer: C
   4. D.Section 5

   Explanation: The CCOHS guide lists "First-aid measures by route of exposure:" in section 4, including eye contact. Sections 5, 6 and 8 address firefighting, accidental release and exposure controls, respectively.

   Reference: CCOHS WHMIS - Safety Data Sheet — What information is on the SDS?, section 4

10. 10A technician finds that an air-suspension accessory leak is lowering the trailer's service-reservoir pressure. Which valve is designed to isolate the accessory supply when pressure falls below its preset?

    1. A.Pressure-protection valveCorrect answer: A
    2. B.One-way check valve
    3. C.Brake relay valve
    4. D.Compressor governor valve

    Explanation: The ICBC manual says pressure-protection valves are "designed to cut off the air supply to these systems if a failed accessory causes the service reservoir pressure to drop below a preset pressure". A one-way check valve restricts reverse flow, a relay valve distributes brake air, and the compressor governor regulates compressor cycling.

    Reference: ICBC Driving Commercial Vehicles — Chapter 8, Pressure-protection valves, page 184