Brake System Components Quiz

Brakes

• Automotive brakes convert kinetic energy to heat through friction, slowing or stopping the vehicle.
• Understanding brake function, components, and types is crucial for vehicle safety, performance, and maintenance efficiency.
• Brakes are a mechanical device that inhibits motion by absorbing energy from a moving system.
• They are used to slow or stop a vehicle, wheel, axle, etc., and prevent motion, primarily through friction.
• Brake functions include slowing and stopping vehicles, controlling vehicles going downhill on slopes, and enabling smooth, safe travel in traffic.

Brake Function

• Brakes slow down or stop the vehicle as required.
• Brakes control the vehicle when rolling down a slope.
• Brakes control the movement of vehicles in heavy traffic flows.

Brake System

• The braking system is a mechanical and/or hydraulic device that slows down vehicles.
• The transmission accelerates the vehicle and the suspension relates to smooth driving.
• The system converts kinetic energy into heat energy through friction.
• Brake pads or shoes push against the vehicle's rotating parts (disks or drums) to slow and stop the vehicle.

Principles of Braking

• Braking converts kinetic energy to heat energy through friction.
• When the driver presses the brake pedal, this action is transmitted to the brake servo using a push rod.
• This lever action amplifies the force, which transmits through the brake booster to the piston in the brake center.
• Hydraulic brake oil is used in the brake main center to pressurise hydraulic fluid.
• The fluid transmits pressure through hydraulic pipes and hoses to the brake cylinders in the wheels and the pistons in the calipers.
• The driver's pedal input is amplified by the servo, generating further pressure.
• The pistons in the cylinders apply pressure to the brake pads, slowing the vehicle.

Disc Brakes

• Disc brakes contain a brake caliper with a piston that moves a brake pad against the disc.
• Pressurized hydraulic fluid pushes the piston towards the disc.
• The disc is fixed to the wheel center and is slowed/stopped via friction from the brake pad against the disc.
• Drum brakes use a wheel cylinder to push brake shoes against a drum causing friction and slowing the vehicle.

Brake Systems and Their Functions

• Disc Brake Mechanism: This is where braking occurs, using hydraulic fluid from the brake main center to push the brake pads against the brake disc.
• Drum Brake Mechanism: Hydraulic fluid sent from the brake main center to the brake cylinder located on the brake plate pushes the brake shoes against the drum, creating friction and slowing the vehicle down. The brake pad often contains the handbrake mechanism.

Brake Fluid

• A specially formulated hydraulic fluid transfers pressure from the master cylinder to calipers and cylinders.
• It must withstand high temperatures and ensure consistent performance in varying conditions.

Brake Pads and Brake Shoes

• Brake Pads: Found in disc brake systems; used in disc brakes, often made of composite or ceramic friction material pressed against the brake rotor.
• Brake Shoes: Used in drum brakes, curved metal plates lined with friction material pressed against the brake drum to create friction for stopping the vehicle.

Brake Calipers (Disc Brakes) or Wheel Cylinders (Drum Brakes):

• Brake Calipers: Found in disc brake systems; contain pistons that squeeze the brake pads against the brake rotor causing friction and slowing the vehicle.
• Wheel Cylinders: Found in drum brake systems; wheel cylinders use hydraulic pressure to push brake shoes against the brake drum, causing friction and slowing the vehicle.

Brake Pedal

• The brake pedal is a lever that transmits force to the brake servo, boosting this force by 5 times.

Brake Servo (Hydrovac(Westinghouse))

• Brake Servo increases pushing force from the brake pedal.
• The pressure is transmitted to the brake main center, and the brake booster vacuum increases the pushing force.

Brake Main Cylinder

• The brake main center is located in front of the brake booster.
• The brake booster converting thrust force into hydraulic pressure.

Brake Fluid Box (Reservoir)

• The brake fluid hydraulic box is located above the brake main cylinder.
• The box stores the brake hydraulic oil which is essential for the brake system.

Brake Limiter (Brake Pressure Proportioner Valve)

• A brake limiter is used in vehicles without ABS and directs 70% of braking pressure to the front wheels and 30% to rear wheels. This is to account for increased vehicle weight on front wheels during braking.

Steps on How to Replace Drum Brakes

• Step 1: Wear an asbestos respirator.
• Step 2: Remove the hubcap and loosen the lug nuts. Block front wheels using wheel chocks. Jack up the vehicle and stabilize using jack stands, avoiding a jack alone. Remove nuts and remove tire.
• Step 3: Spray the hub of the wheel with a penetrating oil such as PB Blaster.
• Step 4: Grab the brake drum by the edges and pull it off. Use the brake adjuster to loosen the brake enough to remove the drum.
• Step 5: Remove any screws holding the drum.
• Step 6: Inspect the drum. If scored replace or reface. Take photos of the components before disassembling.
• Step 7: Place mechanism in a container and spray with brake cleaner to prevent asbestos dust from being airborne.
• Step 8: Compare the new brake shoes with the old ones. Match hole locations and ensure widths are the same.
• Step 9: Dismantle the brake by removing the shoe return springs, parking brake lever, retaining pins, and separating the shoes from the wheel cylinder pins.
• Step 10: Rebuild the new brake by cleaning and lubricating backing plates with anti-seize. Screw the self adjuster back in (check thread direction). Place self adjuster on the new shoes and spread tops to tighten springs. Install shoes and retaining springs. Attach shoes to wheel cylinder pins. Reattach parking brake lever and return springs. Adjust brakes to fit the brake drum using the brake adjustment tool.
• Step 11: Check new brakes with the earlier photo. If different start over.
• Step 12: Put it all back together: Slide the new or resurfaced drum over the wheel studs. Install lock screws to the drum if necessary. Adjust brakes through the drum or backing plate until slight drag is felt. Reinstall the tire. Check brake adjustment and readjust as needed. Remove the jack stand. Lower the jack. Torque the lug nuts and reinstall the hub cover. Repeat on the other side, followed by a road test to confirm proper braking function.

Clutch

• A clutch is a mechanical device transferring engine power to the transmission.
• It's crucial for smooth gear shifting.
• The clutch sits between the engine flywheel and the transmission.

Flywheel

• A flywheel efficiently stores rotational energy (kinetic energy), proportional to its rotational speed squared and mass.
• It resists changes in rotational speed.

Pilot Bearing

• The pilot bearing/bushing supports and centers the transmission input shaft and clutch disc.
• It allows the flywheel to maintain engine RPM while the input shaft slows down and stops.

Clutch Disk

• The clutch disk is a part of the manual transmission system.
• It transfers power from the engine to the transmission.

Pressure Plate

• The pressure plate assembly is secured to the flywheel and clamps the clutch disc against the flywheel to transfer engine power to the transmission. In disengagement, the pressure plate lifts from the flywheel, enabling gear shifting.

Release Bearing

• The release bearing is between the clutch pressure plate and the transmission's release mechanism.
• It transfers force to the clutch plate, using thrust ball bearings.

Clutch Fork and Connecting Linkage

• The clutch fork and connecting linkage convert clutch pedal movement into the throw out bearing's movement.
• This allows pressure plate springs to push against the clutch causing engagement with the flywheel.

Bell Housing (or Bellhousing)

• A colloquial term for the transmission portion that covers the flywheel and clutch assembly.

Clutch Master Cylinder

• A hydraulically operated clutch component found on vehicles with manual transmissions.
• Acts as the pump and pushes fluid through to the clutch slave cylinder for disengagement of the clutch when the pedal is depressed.

Clutch Slave Cylinder

• Works with the clutch master cylinder to disengage the clutch.
• Receives pressure from the master cylinder and pushes a rod or lever to disengage the clutch.

Suspension System

• Suspension connects the vehicle to its wheels and permits relative movement.
• It balances road holding and ride quality, ensuring the wheel is in constant contact with the road.
• This system protects the vehicle and its contents from damage and wear.

Components of the Suspension System

• Suspension Springs: Link wheels/car body, providing ride comfort and stability under various road conditions.
• Leaf Spring: Made from steel that's layered for a reinforced bow-like shape attached to axle and chassis. It provides support for additional vehicle weight.
• Torsion Spring: Uses a metal bar (torsion bar) attached to vehicle and axle/spindle. Twisting of the bar produces resistance to vertical wheel movement.
• Shock Absorber/Damper: Dampens vertical motion/shock impulses (converting kinetic energy into heat), to smooth movement.
• Sway Bar: A U-shaped bar connected to front wheels; limits body roll during vehicle turns.
• Differential: Gear train with three shafts, allowing the vehicle to keep going in curves and bends.
• Tire: Provides traction and cushioning in contact with the road.
• Rim/Mags: The outer edge of the wheel, holding the tire.