brake repairer hydraulic Interview Questions and Answers

1. What are the main components of a hydraulic brake system?

   • Answer: Master cylinder, brake lines, calipers/wheel cylinders, brake pads/shoes, and fluid reservoir.

2. Explain the function of the master cylinder.

   • Answer: The master cylinder converts the force applied to the brake pedal into hydraulic pressure, which is then transmitted to the brakes at each wheel.

3. What is the purpose of brake fluid?

   • Answer: Brake fluid transmits pressure from the master cylinder to the calipers or wheel cylinders, enabling braking action. It must be incompressible and resistant to high temperatures.

4. What are the different types of brake fluid?

   • Answer: DOT 3, DOT 4, DOT 5.1, and DOT 5 (silicone-based, incompatible with other types). Each has different boiling points and properties.

5. How do you check the brake fluid level?

   • Answer: Locate the brake fluid reservoir (usually marked), check the fluid level against the minimum and maximum markings on the reservoir.

6. Why is it important to use the correct type of brake fluid?

   • Answer: Using the incorrect fluid can lead to corrosion, damage to seals, and brake failure due to incompatibility or lower boiling point.

7. Describe the process of bleeding brakes.

   • Answer: Bleeding removes air bubbles from the brake lines. This involves opening a bleeder valve on each caliper/wheel cylinder while pumping the brake pedal to force fluid through and expel air. A helper is usually needed.

8. What tools are typically needed for brake bleeding?

   • Answer: Wrench for the bleeder valve, tubing to connect to the bleeder valve and a container to collect fluid, and a helper to pump the brake pedal.

9. How do you identify a leaking brake line?

   • Answer: Visually inspect the brake lines for rust, corrosion, or wet spots. Look for brake fluid drips or stains.

10. What are the safety precautions when working on brake systems?

    • Answer: Wear safety glasses, gloves, and appropriate clothing. Use jack stands to support the vehicle securely. Never work under a vehicle supported only by a jack. Follow all manufacturer's instructions.

11. Explain the function of brake calipers.

    • Answer: Brake calipers use hydraulic pressure to squeeze brake pads against the rotor, slowing or stopping the wheel.

12. What are the different types of brake calipers?

    • Answer: Fixed calipers (non-floating) and floating calipers.

13. How do you inspect brake pads?

    • Answer: Visually inspect the pads for wear, cracks, or glazing. Measure the pad thickness and compare it to the manufacturer's specifications.

14. What is brake fade?

    • Answer: Brake fade is a reduction in braking effectiveness due to overheating of the brakes. This can lead to reduced stopping power.

15. How do you check for brake fluid leaks?

    • Answer: Visually inspect all components of the hydraulic system for leaks. Look for wet spots, stains, or fluid dripping.

16. What is the purpose of a brake booster?

    • Answer: A brake booster assists the driver in applying brake pressure by using engine vacuum to multiply the force applied to the brake pedal.

17. How do you test a brake booster?

    • Answer: Check for vacuum leaks, check pedal feel (firmness and resistance), and check the vacuum hose connections.

18. What is ABS and how does it work?

    • Answer: Anti-lock Braking System (ABS) prevents wheel lockup during braking, allowing for better steering control and shorter stopping distances.

19. What are the common causes of brake problems?

    • Answer: Worn brake pads, low brake fluid, air in the brake lines, leaking brake lines, faulty master cylinder, faulty calipers, and worn rotors/drums.

20. What is the importance of regular brake maintenance?

    • Answer: Regular maintenance prevents brake failure, ensures optimal braking performance, and extends the life of the brake system components.

21. How often should brake fluid be flushed?

    • Answer: Brake fluid should be flushed and replaced every 2-3 years or according to the manufacturer's recommendations.

22. What is the difference between disc brakes and drum brakes?

    • Answer: Disc brakes use calipers and pads to squeeze a rotor, while drum brakes use shoes that expand against a drum.

23. How do you diagnose a spongy brake pedal?

    • Answer: Check for air in the brake lines, low brake fluid, worn master cylinder, or leaking wheel cylinders/calipers.

24. How do you diagnose a hard brake pedal?

    • Answer: Check for vacuum leaks in the brake booster, low brake fluid, or a faulty master cylinder.

25. What is the procedure for replacing brake pads?

    • Answer: Compress the caliper piston, remove the caliper, remove the old brake pads, install the new brake pads, reassemble the caliper, and check for proper clearance.

26. How do you inspect brake rotors for wear?

    • Answer: Measure the rotor thickness using a caliper, check for scoring, cracks, or excessive runout.

27. What is the procedure for replacing brake rotors?

    • Answer: Remove the wheel, remove the caliper, remove the old rotor, install the new rotor, reassemble the caliper, and check for proper clearance.

28. What is the importance of torque specifications when working on brakes?

    • Answer: Using the correct torque ensures that components are properly tightened, preventing loosening and damage.

29. How do you identify a seized caliper?

    • Answer: Check for difficulty rotating the wheel, uneven brake pad wear, or overheating.

30. What is the procedure for replacing a brake caliper?

    • Answer: Remove the wheel, remove the brake lines, remove the caliper mounting bolts, remove the caliper, install the new caliper, bleed the brakes, and check for leaks.

31. How do you inspect brake lines for damage?

    • Answer: Visually inspect the lines for kinks, rust, corrosion, cracks, or leaks.

32. What is the procedure for replacing a brake line?

    • Answer: Disconnect the old brake line, install the new brake line, bleed the brakes, and check for leaks.

33. What are the common types of brake hose materials?

    • Answer: Rubber and synthetic rubber.

34. How do you inspect brake hoses for damage?

    • Answer: Visually inspect the hoses for cracks, bulges, or leaks. Squeeze the hose to check for softness or sponginess.

35. What is the procedure for replacing a brake hose?

    • Answer: Disconnect the old brake hose, install the new brake hose, bleed the brakes, and check for leaks.

36. What is the importance of proper wheel cylinder lubrication?

    • Answer: Proper lubrication reduces friction and wear, ensuring smooth operation and extending the life of the wheel cylinder.

37. What type of lubricant should be used on brake components?

    • Answer: A high-quality brake caliper grease is recommended. Never use general purpose grease.

38. How do you properly dispose of used brake fluid?

    • Answer: Dispose of used brake fluid according to local regulations and environmental guidelines. Many automotive parts stores accept used brake fluid for recycling.

39. What are the symptoms of a failing master cylinder?

    • Answer: Spongy brake pedal, hard brake pedal, low brake fluid level, brake fluid leaks.

40. What is the procedure for replacing a master cylinder?

    • Answer: Drain the brake fluid reservoir, disconnect brake lines, remove the master cylinder, install the new master cylinder, bleed the brakes, and check for leaks.

41. How do you test a wheel cylinder?

    • Answer: Check for leaks, check for proper sealing, and check for free movement of the pistons.

42. What is the procedure for replacing a wheel cylinder?

    • Answer: Remove the wheel, remove the brake drum, remove the wheel cylinder, install the new wheel cylinder, adjust the brakes, bleed the brakes, and check for leaks.

43. How do you diagnose a pulsating brake pedal?

    • Answer: Warped rotors, worn brake pads, or a faulty ABS sensor.

44. How do you diagnose a grinding noise during braking?

    • Answer: Worn brake pads, worn rotors, or metallic debris in the brakes.

45. How do you diagnose a squealing noise during braking?

    • Answer: Worn brake pads, glazed brake pads, or low brake fluid.

46. What is the importance of using a torque wrench?

    • Answer: To ensure that bolts are tightened to the correct specification, preventing damage to components.

47. What safety precautions should be taken when working with brake components?

    • Answer: Wear safety glasses, gloves, and appropriate clothing. Use jack stands to support the vehicle securely. Never work under a vehicle supported only by a jack. Follow all manufacturer's instructions.

48. What is the proper way to store brake parts?

    • Answer: In a clean, dry place, away from moisture and extreme temperatures.

49. What are some common mistakes made when working on brakes?

    • Answer: Not bleeding the brakes properly, not using the correct torque specifications, not replacing worn components, and improper lubrication.

50. Describe the different types of brake system designs.

    • Answer: Hydraulic, vacuum assist, ABS, and electronic brake control systems.

51. What is the difference between a single and dual master cylinder?

    • Answer: A single master cylinder controls both front and rear brakes, while a dual master cylinder has separate circuits for front and rear, increasing safety in case of failure.

52. How do you inspect brake lines for corrosion?

    • Answer: Look for rust, pitting, or any signs of degradation, especially in areas prone to moisture or salt exposure.

53. What are the signs of a failing brake proportioning valve?

    • Answer: Uneven braking, pulling to one side during braking, or excessive rear wheel lockup.

54. What is the function of a brake pressure regulator?

    • Answer: Controls brake pressure to the rear wheels, preventing rear-wheel lockup, especially during heavy braking.

55. How do you diagnose a problem with a parking brake?

    • Answer: Check the cable for fraying or damage, check for proper adjustment, and check the brake shoes for wear.

56. What are the safety considerations when working on a vehicle’s braking system?

    • Answer: Always use jack stands, never work under a vehicle supported only by a jack, wear safety glasses and gloves, and follow all manufacturer's instructions and safety protocols.

57. What tools and equipment are essential for brake repair?

    • Answer: Torque wrench, socket set, brake bleeder kit, caliper tool, pry bar, jack stands, safety glasses, gloves.

58. Explain the importance of using the correct size brake parts.

    • Answer: Using the incorrect size parts can lead to improper fit, damage to components, and brake failure.

59. Describe the process of cleaning brake components.

    • Answer: Use brake cleaner to remove grease, dirt, and other contaminants. Ensure all components are completely dry before reassembly.

60. What are the common causes of brake noise and how do you troubleshoot them?

    • Answer: Worn pads, warped rotors, loose components. Troubleshooting involves visual inspection, listening for the source of the noise, and checking for wear and tear.

61. Explain the concept of brake bias.

    • Answer: Brake bias refers to the distribution of braking force between the front and rear wheels. It is important for balanced braking and preventing skidding.

62. What is the role of a proportioning valve in brake bias?

    • Answer: It regulates the brake pressure to the rear wheels to help maintain proper bias, preventing rear wheel lockup.

63. How do you check for brake line leaks using a pressure tester?

    • Answer: Connect the pressure tester to the brake system, pressurize the system, and visually inspect for leaks while monitoring the pressure gauge.

64. What is the significance of maintaining the correct brake fluid level?

    • Answer: Low fluid level reduces braking effectiveness and can lead to air entering the system. Excessive fluid can lead to system pressure issues.

65. How do you determine if brake pads are worn down?

    • Answer: Visually inspect for thickness, listen for scraping sounds, or use a feeler gauge to measure pad thickness.

66. What are the potential consequences of neglecting brake maintenance?

    • Answer: Brake failure, accidents, increased stopping distances, damage to other brake components.

67. Explain the importance of properly torquing caliper bolts.

    • Answer: Incorrect torque can lead to loose calipers, affecting braking performance and potentially leading to caliper failure.

Thank you for reading our blog post on 'brake repairer hydraulic Interview Questions and Answers'.We hope you found it informative and useful.Stay tuned for more insightful content!