Vacuum clutches use the existing vacuum in the engine manifold to operate the clutch. The vacuum clutch consists of an oil tank, a check valve, a vacuum cylinder with a piston, and a solenoid valve.

When the throttle valve is open, the pressure in the intake manifold increases as a result of which the valve check valve closes. It separates the reservoir and manifold so there is always a vacuum in the reservoir.

In normal operation, the solenoid stem is in the bottom position of the valve and the switch in the shift lever remains open. At this stage, atmospheric pressure acts on both sides of the vacuum cylinder piston, because the vacuum cylinder communicates with the atmosphere through the exhaust port.

When the driver shifts gear by holding the gear lever, the switch closes. The solenoid energizes and pulls the valve up, which connects one side of the vacuum cylinder to the reservoir. This action opens the passage between the vacuum cylinder and the container. Due to the pressure difference, the vacuum cylinder piston moves back and forth.

This piston motion is transmitted through the connecting rod to the clutch, causing it to disengage. When the driver is not operating the gear lever, the switch is open and the clutch remains engaged due to spring force.

The working operation of the hydraulic clutch is the same as that of the vacuum clutch. The main difference between the two is that hydraulic clutches are operated by oil pressure whereas vacuum clutches are operated by vacuum.

It has fewer parts than other clutches. It consists of accumulators, control valves, cylinders with pistons, pumps, and reservoirs.

When the throttle valve is open, the pressure in the intake manifold increases as a result of which the valve check valve closes. It separates the reservoir and manifold so there is always a vacuum in the reservoir.

When the driver shifts gear by holding the gear lever, the switch closes. The solenoid energizes and pulls the valve up, which connects one side of the vacuum cylinder to the reservoir. This action opens the passage between the vacuum cylinder and the container. Due to the pressure difference, the vacuum cylinder piston moves back and forth.

This piston motion is transmitted through the connecting rod to the clutch, causing it to disengage. When the driver is not operating the gear lever, the switch is open and the clutch remains engaged due to spring force.

Taizhou Benwo Auto Parts Co., Ltd. Is a racing clutch kit factory from China. The company mainly sells truck clutch kit series products.