A hydraulic brake uses liquid pressure to transfer force from the brake pedal to the brake drum to stop a vehicle.
In this working model, you will show how pressing a “brake pedal” moves hydraulic fluid (water or oil) through a tube to push a “brake shoe” against a “drum” (wheel).
Working Principle Demonstrated:
Pascal’s Law: Pressure applied on a fluid is transmitted equally in all directions.
Friction: Brake shoe presses against the wheel to create friction and stop movement.
Materials Needed:
- Cardboard sheets (for base and structures)
- 2 plastic syringes (10 ml or 20 ml)
- Rubber tube/IV tube (to connect syringes)
- DC motor (low rpm — like 30-60 RPM)
- 9V battery and battery clip
- Switch (for motor control)
- Small plastic wheel or cardboard disc (for rotating drum)
- Glue gun / Fevicol / Tape
- Nails, pins, or sticks (for support)
- Skewer stick / metal rod (to attach rotating drum to motor)
- Scissors, cutter, ruler, marker
- Water (to fill syringes)
How to Make the hydraulic drum brakes Model:
1. Create the Base:
- Cut a strong rectangular base from cardboard (about 30 cm x 20 cm).
- This base will hold the motor, drum, and brake pads.
2. Prepare the Rotating Drum:
- Cut a circular disc (about 10–15 cm diameter) from thick cardboard or use a small plastic wheel.
- Attach this disc firmly to a skewer stick or small rod.
- Connect the rod to the shaft of the DC motor using glue or a small connector (straw, pipe).
3. Install the DC Motor:
- Fix the DC motor onto the cardboard base so that it can rotate the drum horizontally.
- Wire the motor to the 9V battery through a switch for easy control.
4. Make Hydraulic Brake System:
- Fill one syringe with water (no air bubbles inside).
- Connect both syringes using a rubber tube.
(Push and pull in one syringe — the second syringe will react accordingly.)
5. Create Brake Pads:
- Cut two small rectangular pieces from cardboard to act as brake pads.
- Attach each brake pad to the plunger of the second syringe using glue.
- Fix the second syringe firmly beside the rotating drum (without blocking rotation).
- Position the brake pads facing the sides of the rotating drum, so when you push the first syringe, brake pads move inward and touch the drum.
6. Final Assembly:
- Secure all parts properly using glue and tape.
- Make sure the drum rotates freely when brakes are not applied.