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Automobile & Light Truck Certification Test A5 Brakes practice questions

216 free questions with answers and explanations.

Practice test
  1. 1.A technician is setting up a bench-type brake lathe to machine a drum. After mounting the drum on the arbor, the technician uses a dial indicator on the drum's friction surface. The indicator shows excessive runout (more than 0.006 inches). What is the FIRST step the technician should take to correct this issue?Machining
  2. 2.A technician is machining a brake rotor and notices that the lathe continuously produces a tapered cut, even after re-mounting the rotor multiple times and checking for runout. The outer edge of the rotor is consistently thicker than the inner edge. What is the MOST likely cause of this persistent issue on a bench-type lathe?Machining
  3. 3.A technician is machining a brake drum and observes that the drum's friction surface is glazing over, appearing shiny and hard, rather than producing a clean metal finish. What adjustment should the technician make to the lathe settings to correct this condition?Machining
  4. 4.A technician is machining a brake rotor on an on-car brake lathe. After several passes, the technician observes a slight taper across the rotor surface, with the outer edge being thicker than the inner edge. Which of the following is the MOST likely cause of this condition?Machining
  5. 5.A technician is machining a brake drum that exhibits significant hard spots, causing the cutting tool to chatter and produce an inconsistent finish. Which of the following is the MOST effective method to address this issue during machining?Machining
  6. 6.A technician is machining a brake rotor and observes that the cutting tool is producing an uneven, torn, and rough surface finish, accompanied by significant chatter. The tool bits are new and properly installed. What is the MOST likely cause of this issue?Machining
  7. 7.A technician is machining a brake drum. The drum has a maximum diameter specification of 250.0 mm. After machining, the technician measures the drum at 250.2 mm. What is the MOST appropriate action for the technician to take?Machining
  8. 8.When machining a brake rotor, what is the primary purpose of taking a 'cleanup pass' or 'finishing pass' with a very light depth of cut?Machining
  9. 9.A technician is inspecting a brake rotor that has been machined. The rotor surface shows a series of fine, concentric grooves, often referred to as a 'phonograph record' finish. What is the MOST likely cause of this condition?Machining
  10. 10.A technician is preparing to machine a severely grooved brake rotor. Before starting, they measure the rotor's thickness at 22.0 mm. The minimum allowable thickness stamped on the rotor is 20.0 mm. The maximum amount of material that can be removed from each side of the rotor is 0.5 mm per pass. What is the MOST critical consideration before machining this rotor?Machining
  11. 11.A technician is diagnosing a heavy-duty truck equipped with an air-over-hydraulic brake system. The driver reports a hard brake pedal and slow brake release. An inspection reveals that the air compressor is building sufficient pressure, and there are no external air leaks. Which of the following components is MOST likely causing these symptoms?Power Assist Unit Diagnosis and Repair
  12. 12.During a pre-purchase inspection, a technician notices that the brake pedal on a vacuum-assisted vehicle feels firm with the engine off. When the engine is started, the pedal drops slightly, but then slowly continues to sink towards the floor while steady pressure is maintained. This symptom is MOST indicative of:Power Assist Unit Diagnosis and Repair
  13. 13.A technician is diagnosing a vehicle with an electric power steering (EPS) system that has a 'stiff' or 'heavy' steering feel, but no warning lights are illuminated on the dash. A scan tool reveals no Diagnostic Trouble Codes (DTCs). Which of the following should the technician investigate FIRST?Power Assist Unit Diagnosis and Repair
  14. 14.A technician is inspecting a vehicle with a hydro-boost brake system. The customer complains of a hard brake pedal and excessive effort required for steering, especially at low engine RPMs. Upon inspection, the power steering fluid reservoir is found to be below the 'add' mark, and the fluid appears dark and burnt. What is the MOST likely cause?Power Assist Unit Diagnosis and Repair
  15. 15.A technician is performing a pre-delivery inspection on a new electric vehicle (EV) equipped with an Integrated Power Brake (IPB) system. The service manual specifies a procedure for 'IPB System Calibration' after certain repairs. What is the PRIMARY reason for this calibration?Power Assist Unit Diagnosis and Repair
  16. 16.A vehicle with a vacuum-assisted brake booster has a hard brake pedal. The technician observes that the engine idles rough when the brake pedal is depressed. Which of the following is the MOST likely cause?Power Assist Unit Diagnosis and Repair
  17. 17.An electric power assist steering (EPAS) system is being diagnosed. The scan tool shows a C0550 DTC (Electronic Control Unit Internal Fault). The steering feels heavy at all speeds, but there are no other warning lights ON, and the charging system is functioning correctly. What is the MOST appropriate next step for the technician?Power Assist Unit Diagnosis and Repair
  18. 18.A customer reports that their vehicle's brake pedal is very hard to push, requiring excessive force to slow down. The engine idle speed is normal, and there are no apparent vacuum leaks. A vacuum gauge connected to the booster hose reads 18 in. Hg with the engine running. What is the MOST likely cause of the hard pedal?Power Assist Unit Diagnosis and Repair
  19. 19.A vehicle equipped with an electric power brake booster (i-Booster) experiences intermittent loss of power assist and illuminates the 'Brake System' warning light. A scan tool reveals a DTC related to the booster's internal motor circuit. Which of the following is the MOST common repair strategy for such a component?Power Assist Unit Diagnosis and Repair
  20. 20.A vehicle with an electro-hydraulic power steering system (EHPAS) that also provides power brake assist experiences a complete loss of power steering and power brakes. The technician confirms the serpentine belt is intact and the engine is running. What is the MOST likely cause of this dual failure?Power Assist Unit Diagnosis and Repair
  21. 21.A vehicle equipped with a hydro-boost brake system exhibits a hard brake pedal and a noticeable increase in steering effort when the brake pedal is depressed. The power steering fluid level is correct, and the power steering pump appears to be functioning normally at idle. Which component is MOST likely at fault?Power Assist Unit Diagnosis and Repair
  22. 22.A technician is diagnosing a spongy brake pedal on a vehicle equipped with a vacuum-assisted power brake system. Initial checks confirm adequate fluid level and no external leaks. The technician then depresses the brake pedal with the engine off several times until the pedal becomes firm. While holding the pedal down, the engine is started. If the pedal does not fall slightly and then hold, which of the following is the MOST likely cause?Power Assist Unit Diagnosis and Repair
  23. 23.A technician is diagnosing a vehicle with a vacuum power brake booster. The customer reports that the brake pedal feels hard and requires excessive effort to stop the vehicle, especially after making several stops in traffic. Testing reveals that engine vacuum at idle is 18 inHg, but after 3-4 rapid pedal applications, the vacuum drops to 5 inHg and recovers slowly. Which of the following is the MOST likely cause?Power Assist Unit Diagnosis and Repair
  24. 24.A technician is diagnosing a vehicle with an electric vacuum pump that supplies vacuum to the brake booster. The customer reports a hard brake pedal on cold starts and occasional extended stopping distances. The technician finds no vacuum leaks in the lines or booster, and the engine vacuum is normal when measured directly at the intake manifold. What is the MOST likely cause?Power Assist Unit Diagnosis and Repair
  25. 25.A vehicle with a vacuum power brake booster exhibits a loud hissing sound from the brake pedal area when the pedal is depressed. The pedal feels hard, and engine idle quality noticeably drops when the brakes are applied. What is the MOST likely cause?Power Assist Unit Diagnosis and Repair
  26. 26.Which of the following is a common characteristic of a vehicle equipped with an electro-hydraulic power brake system (EHPB) compared to a traditional vacuum-assist system?Power Assist Unit Diagnosis and Repair
  27. 27.A technician is performing a road test on a vehicle with a vacuum-assisted brake booster. The customer complains that the brakes feel normal initially, but after several rapid applications, the pedal becomes hard. Which of the following is the MOST likely cause?Power Assist Unit Diagnosis and Repair
  28. 28.Which of the following components is responsible for maintaining a reserve of hydraulic pressure for brake assist in a hydro-boost system, even after the engine has been shut off?Power Assist Unit Diagnosis and Repair
  29. 29.A vehicle with an electric power steering (EPS) system has a diagnostic trouble code (DTC) indicating a 'Steering Position Sensor Circuit Malfunction'. The customer reports intermittent heavy steering and occasional loss of power assist. Which of the following is the MOST appropriate next step for the technician?Power Assist Unit Diagnosis and Repair
  30. 30.A technician is performing a brake system inspection on a vehicle with a 'soft' brake pedal. The master cylinder reservoir is full, and there are no external leaks. When the technician depresses the pedal, it slowly sinks to the floor even with steady pressure. Which of the following is the MOST likely cause?Hydraulic System Diagnosis and Repair
  31. 31.A technician is troubleshooting a vehicle that exhibits a 'dragging' brake on the front left wheel after the brake pedal is released. The master cylinder is functioning correctly, and the caliper slides are well-lubricated. What is the MOST likely cause of this condition?Hydraulic System Diagnosis and Repair
  32. 32.A vehicle with an ABS system exhibits a 'hard pedal' symptom. After inspecting the conventional hydraulic components and finding no issues, the technician suspects an ABS-related problem. Which of the following ABS components, if faulty, could cause a hard pedal?Hydraulic System Diagnosis and Repair
  33. 33.A vehicle's brake system utilizes a low-drag caliper design. To ensure proper operation after pad replacement, which of the following bleeding procedures is MOST likely recommended by the manufacturer?Hydraulic System Diagnosis and Repair
  34. 34.A technician is diagnosing a vehicle with a spongy brake pedal that gradually firms up after several pumps. The master cylinder reservoir is full, and there are no visible external leaks. The technician suspects air in the hydraulic system. If bleeding the brakes manually does not resolve the issue, and the problem persists, which of the following is the MOST likely location for the trapped air?Hydraulic System Diagnosis and Repair
  35. 35.A technician is installing a new section of steel brake line. After double flaring the end of the line, they attempt to connect it to a caliper. The fitting threads on easily, but when tightened, a small leak persists. The technician confirms the flare nut is the correct size and the line is not cross-threaded. What is the MOST likely cause of the leak?Hydraulic System Diagnosis and Repair
  36. 36.A technician is diagnosing a spongy brake pedal feel that improves after several rapid pumps. Which of the following is the most likely cause?Hydraulic System Diagnosis and Repair
  37. 37.A technician is diagnosing a vehicle with a spongy brake pedal that gradually firms up after several rapid pumps. There are no visible external leaks. Which of the following is the MOST likely cause?Hydraulic System Diagnosis and Repair
  38. 38.A technician is installing new steel brake lines on a vehicle. They are using a double flaring tool to create the correct flare type for the connections. After creating the flare, the technician notices that the flare appears uneven and slightly cracked at the base. What is the MOST likely cause of this issue?Hydraulic System Diagnosis and Repair
  39. 39.A technician is performing a brake inspection on an older vehicle equipped with a combination valve. The front brakes lock up prematurely during a hard stop, while the rear wheels barely engage. Which of the following is the MOST likely cause?Hydraulic System Diagnosis and Repair
  40. 40.A technician is evaluating a brake system that uses a combination valve. The vehicle exhibits normal braking under light pedal pressure, but when heavy braking is applied, the rear wheels tend to lock up prematurely. The front brakes seem to be doing most of the work. Which function of the combination valve is MOST likely failing?Hydraulic System Diagnosis and Repair
  41. 41.A technician is pressure bleeding a brake system. The pressure bleeder is set to 15 PSI. After connecting the bleeder to the master cylinder reservoir and opening the bleeder screw at the furthest wheel, the technician notices that fluid flow is slow and inconsistent. What is the MOST likely cause?Hydraulic System Diagnosis and Repair
  42. 42.A technician is inspecting a vehicle for a brake fluid leak. They discover a small leak at the connection point between a steel brake line and a brass fitting. Which of the following is the MOST likely cause of this leak?Hydraulic System Diagnosis and Repair
  43. 43.A technician is performing a brake fluid flush on a vehicle. The manufacturer specifies using a pressure bleeder set to 15-20 PSI. After attaching the pressure bleeder and opening the bleeder screws, the technician notices that the fluid flow is inconsistent and sometimes stops completely, even though the pressure gauge on the bleeder shows a steady 18 PSI. What is the MOST likely reason for this inconsistent flow?Hydraulic System Diagnosis and Repair
  44. 44.A vehicle experiences a sudden, complete loss of braking in one hydraulic circuit (e.g., front brakes). The driver notices the brake pedal suddenly drops lower than usual, but they can still achieve some braking with increased pedal effort. Which component is specifically designed to alert the driver to this type of pressure differential and illuminate a warning light?Hydraulic System Diagnosis and Repair
  45. 45.A technician is inspecting a vehicle with a complaint of delayed brake release on one front wheel. After checking for caliper issues and hose restrictions, they decide to test the flexible brake hose using a pair of vice grips. They clamp the flexible hose leading to the affected caliper and then depress the brake pedal. If the hose is internally collapsed, what would the technician observe when clamping the hose and depressing the pedal?Hydraulic System Diagnosis and Repair
  46. 46.A technician is inspecting a vehicle that has recently had new brake pads and rotors installed. The customer complains that the brake pedal feels 'low' and requires excessive travel before the brakes engage, but braking performance is otherwise good. Which of the following is the MOST likely cause?Hydraulic System Diagnosis and Repair
  47. 47.A technician is performing a bench bleed on a new master cylinder before installation. After connecting the lines and filling the reservoir, they slowly push the primary piston in and then release it, repeating the process. What is the PRIMARY purpose of this procedure?Hydraulic System Diagnosis and Repair
  48. 48.A technician is performing a manual brake bleed on a vehicle. After bleeding the right rear, left rear, and right front calipers, they move to the left front. The pedal feels firm, but no fluid comes out when the left front bleeder screw is opened. Which of the following is the most likely cause?Hydraulic System Diagnosis and Repair
  49. 49.A vehicle's brake system is equipped with a pressure differential valve. If a technician observes the brake warning light illuminated on the dashboard, but there are no visible external leaks, what is the MOST likely cause?Hydraulic System Diagnosis and Repair
  50. 50.A technician is diagnosing a spongy brake pedal on a vehicle. After inspecting for external leaks and ensuring proper fluid level, they attempt to bleed the brakes manually. During bleeding, the technician observes that the fluid coming from the bleeder screw contains numerous small bubbles, even after several cycles. Which of the following is the MOST likely cause of this condition?Hydraulic System Diagnosis and Repair