Lesson Note on Braking System—Faults in Braking System: Remove Brake to Find Fault for SS2

Class: Senior Secondary School 2 (SS2 / SSS2)
Term: 3rd Term
Week: 5
Age: 16 years
Duration: 45 minutes
Subject: Auto Mechanic Work
Curriculum Theme: Vehicle Maintenance
Previous Lesson: Braking System—Faults in Braking System: Wheel Cylinder Operation.
Topic: BRAKING SYSTEM— FAULTS IN BRAKING SYSTEM.
Subject Matter: Meaning of BRAKING SYSTEM— FAULTS IN BRAKING SYSTEM (definition of braking faults), remove the brake to find out the fault (inspection, diagnosis), simple brake adjustment on an hydraulic operation (basic adjustment)

Specific Objectives

By the end of the lesson, pupils should be able to:

Cognitive Domain:

• Define braking system faults.
• Identify common types of faults in a vehicle’s braking system.

Affective Domain:

• Appreciate the importance of proper brake diagnosis and adjustment for vehicle safety.
• Develop safety consciousness when working on vehicle brake systems.

Psychomotor Domain:

• Demonstrate the correct procedure for removing brake components for inspection.
• Carry out a simple brake adjustment on an hydraulic braking system.

Social Domain:

• Work collaboratively in groups during practical sessions to diagnose and adjust brakes.

Reference Materials

The following resources were used in planning this lesson:

• Senior Secondary Schools Education Curriculum
• State Unified Scheme of Work
• Automobile Mechanics for Senior Secondary Schools by [Author/Publisher, e.g., Evans Brothers]
• https://www.google.com/search?q=auto+mechanic+textbook+nigeria
• https://www.youtube.com/results?search_query=braking+system+faults+diagnosis

Instructional Materials

The teacher will teach this lesson with the aid of:

• A complete toolbox (wrenches, screwdrivers, pliers, etc.)
• A live vehicle with a hydraulic braking system (or a cut-away model)
• Safety equipment (jack, jack stands, wheel chocks, safety goggles)
• Brake fluid, brake cleaner, and rags

Rationale for the Lesson

Understanding braking system faults and their diagnosis is important for pupils because it equips them with the skills to maintain vehicle safety and performance. This knowledge is essential for preventing accidents and ensuring the longevity of a vehicle’s braking components.

Prerequisite/Previous Knowledge

Pupils are expected to have basic knowledge of vehicle components, general safety procedures in a workshop, and the basic function of a vehicle’s braking system.

Lesson Content/Board Summary

Braking System Faults

Introduction to Braking System Faults

Braking system faults refer to any malfunction or defect in the components of a vehicle’s braking system that compromises its ability to slow down or stop the vehicle effectively. These faults can lead to reduced braking performance, increased stopping distances, and potential safety hazards.

Common Braking System Faults

The following are common faults found in braking systems:

• Spongy Brake Pedal: Often caused by air in the hydraulic lines or a faulty master cylinder.
• Hard Brake Pedal: May indicate a problem with the brake booster or a restricted brake line.
• Brakes Pulling to One Side: Can be due to seized calipers, worn brake pads on one side, or brake fluid contamination.
• Squealing/Grinding Noise: Typically indicates worn brake pads (metal-on-metal contact) or contaminated pads.
• Vibration During Braking: Usually caused by warped brake rotors or drums.
• Brake Fluid Leaks: Can occur from brake lines, calipers, wheel cylinders, or the master cylinder, leading to loss of braking pressure.
• Excessive Brake Pedal Travel: May suggest worn brake pads, improper adjustment, or low brake fluid.

Procedure for Removing Brakes to Find Faults (Inspection and Diagnosis)

Proper inspection and diagnosis are critical to identifying brake faults. Follow these steps:

1. Prepare the Vehicle: Park the vehicle on a level surface, engage the parking brake, and place wheel chocks behind the wheels not being worked on.
2. Safely Lift and Support: Use a jack to lift the vehicle and secure it on jack stands. Never work under a vehicle supported only by a jack.
3. Remove the Wheel: Loosen the lug nuts, then remove the wheel to expose the brake assembly.
4. Visual Inspection:
   • Inspect brake pads/shoes for wear, cracks, or contamination.
   • Check rotors/drums for scoring, warping, or excessive wear.
   • Look for leaks around calipers, wheel cylinders, and brake lines.
   • Examine brake lines and hoses for cracks, bulges, or corrosion.
   • Check the master cylinder for fluid level and leaks.
5. Remove Brake Components (if necessary for deeper inspection):
   • For disc brakes: Remove caliper bolts and carefully slide the caliper off the rotor. Suspend the caliper to avoid straining the brake hose.
   • For drum brakes: Remove the drum retaining screws (if any) and pull the drum off. Inspect the brake shoes, springs, and wheel cylinder.
6. Identify the Fault: Based on observations, pinpoint the specific fault (e.g., worn pads, leaking caliper, warped rotor).

Simple Brake Adjustment on an Hydraulic Operation

Some hydraulic braking systems, especially older drum brakes, require periodic adjustment. Disc brakes are generally self-adjusting. This procedure focuses on manual adjustment for drum brakes:

1. Access the Adjuster: For most drum brakes, there is an access hole on the backing plate or through the wheel lug hole. Remove the rubber plug covering the adjuster.
2. Locate the Star Wheel Adjuster: Use a brake spoon or a flat-head screwdriver to engage the teeth of the star wheel adjuster.
3. Adjust the Brakes:
   • Rotate the star wheel adjuster until the brake shoes make light contact with the drum. You should hear a slight drag when rotating the wheel by hand.
   • If the wheel locks up, back off the adjuster slightly until the wheel spins freely with a slight drag.
   • Adjust both sides of the axle evenly to prevent the vehicle from pulling to one side during braking.
4. Test the Adjustment: With the vehicle still on jack stands, test the brake pedal feel. It should feel firm. Start the engine and test again.
5. Road Test: After lowering the vehicle, perform a gentle road test in a safe area to ensure proper braking and no pulling.

Teaching Methods/Instructional Techniques

Discussion, Lecture, Demonstration, Question and Answer, Visual Aids, Practical Session

Instructional Procedures

Step 1: Introduction

Time: 5 minutes
Teaching Skill: Set Induction
Teacher’s Activity: The teacher greets the pupils, reviews the previous lesson on the general function of a braking system, and then introduces the topic of braking system faults, emphasizing its importance for vehicle safety.
Pupils’ Activity: Pupils respond to greetings, recall the previous lesson, and listen attentively to the introduction of the new topic.
Learning Point: Pupils are prepared for the lesson and understand the relevance of the topic.

Step 2: Braking System Faults: Definition and Types

Time: 8 minutes
Teaching Skill: Explanation/Discussion
Teacher’s Activity: The teacher defines braking system faults and discusses various common types of faults, such as spongy pedal, hard pedal, pulling to one side, and grinding noises, using examples from the board summary.
Pupils’ Activity: Pupils listen, take notes, and ask questions for clarification regarding the definitions and types of faults.
Learning Point: Pupils understand what braking system faults are and can identify common types.

Step 3: Procedure for Removing Brakes for Inspection

Time: 10 minutes
Teaching Skill: Demonstration/Instruction
Teacher’s Activity: The teacher demonstrates the safe procedure for removing brake components for inspection on the live vehicle, highlighting safety precautions like using jack stands and explaining what to look for during visual inspection.
Pupils’ Activity: Pupils observe the demonstration carefully, noting the steps and safety measures, and ask questions about the procedure.
Learning Point: Pupils learn the correct and safe method for disassembling brake components for fault diagnosis.

Step 4: Simple Brake Adjustment on Hydraulic Operation

Time: 7 minutes
Teaching Skill: Demonstration/Practical Guidance
Teacher’s Activity: The teacher demonstrates a simple brake adjustment on an hydraulic system (e.g., drum brake adjustment) if applicable to the vehicle, explaining the purpose and how to achieve the correct adjustment.
Pupils’ Activity: Pupils observe the adjustment process, paying attention to the tools used and the specific actions taken to adjust the brakes.
Learning Point: Pupils understand the process and importance of simple brake adjustments.

Step 5: Evaluation/Review

Time: 10 minutes
Teaching Skill: Questioning/Assessment
Teacher’s Activity: The teacher evaluates the learning by asking the following questions:

1. What is a braking system fault?
2. List three common faults that can occur in a vehicle’s braking system.
3. Briefly explain two steps involved in removing a brake for inspection.
4. Why is it important to adjust drum brakes properly?

Pupils’ Activity: Pupils answer orally and in writing.
Learning Point: Pupils demonstrate understanding of the lesson.

Step 6: Conclusion

Time: 5 minutes
Teaching Skill: Summarization/Assignment
Teacher’s Activity: The teacher summarizes the key points of the lesson, reiterating the importance of brake system maintenance for safety. The teacher then assigns homework for pupils to research advanced brake system faults.
Pupils’ Activity: Pupils listen to the summary, ask any final questions, and copy down the homework assignment.
Learning Point: Pupils consolidate their learning and are given further study tasks.

Lesson Keywords

• Braking system – The mechanism in a vehicle that slows or stops its movement.
• Faults – Malfunctions or defects in the braking system.
• Diagnosis – The process of identifying the cause of a fault.
• Hydraulic – Relating to the use of liquid (brake fluid) under pressure to transmit force.
• Adjustment – The process of setting brake components to their correct operating positions.
• Master cylinder – A component that converts pedal pressure into hydraulic pressure.
• Brake pads – Friction material that presses against the rotor in disc brakes.
• Brake fluid – The hydraulic fluid used to transmit pressure in the braking system.

Differentiation

The teacher will group pupils for practical activities, allowing more experienced pupils to assist those who are less familiar with the procedures. Additional support will be provided to struggling pupils through one-on-one guidance, while fast learners will be encouraged to explore more complex diagnostic scenarios.

Note for teachers using this lesson plan

Emphasize safety protocols at all times during practical demonstrations and activities. Ensure that all pupils have a clear view of the demonstrations. Encourage active participation and questions. If a live vehicle is not available, use diagrams, videos, or disassembled components to illustrate the concepts and procedures.