Pneumatic brake booster Kamaz

The pneumatic booster is mounted on the clutch housing on the right side of the power unit. The amplifier body consists of two parts

The front 14 of the body is made of aluminum alloy, and the rear 16 is made of cast iron.

A gasket is installed between these parts, which is also the membrane 9 of the tracking device placed on top.

Pneumatic clutch booster for Kamaz

The tracking device provides automatic change of air pressure on the pneumatic piston 13 depending on the pressure in the hydraulic clutch.

The main parts of the follower include the follower piston 6 with a cuff, inlet 11 and outlet 12 valves (valve block), membrane 9 and springs.

When the clutch pedal is released (clutch engaged), the pneumatic piston 13 and the clutch release piston 15 are in the extreme right (front) position (the pneumatic piston takes this position under the influence of a return spring).

The pressure in the cavity in front of the piston and behind the piston corresponds to atmospheric pressure.

The position of the piston 15 for disengaging the clutch is determined by the stop of its pusher in the bottom of the pneumatic piston.

In the tracking device, the outlet valve 12 is open, and the inlet valve 11 is closed.

When you press the clutch pedal, the working fluid flows under pressure to hole A, creating pressure in the cavity of the clutch release cylinder and at the end of the follower piston 6.

Under the pressure of the working fluid, the follower piston acts on the valve block, closing the exhaust valve 12 and opening the inlet valve 11.

Compressed air supplied through pipelines to hole B begins to flow into the pneumatic cylinder.

Under the pressure of compressed air, the pneumatic piston 13 moves, acting on the piston rod.

As a result, the total force acts on the pusher 3 of the clutch release piston 15, which ensures complete disengagement of the clutch when the driver presses the pedal with a force of 150 N.

When the pedal is released, the pressure in front of the follower piston 6 drops, as a result of which the inlet valve closes in the follower and the exhaust valve opens.

Compressed air from the pneumatic cylinder is gradually released into the atmosphere, the pressure drops, the fluid from the hydraulic cylinder flows into the main cylinder and the clutch mechanism is activated.

In the absence of compressed air in the pneumatic system, the clutch control remains possible, since the clutch can be disengaged due to pressure in the hydraulic part of the booster. But at the same time, the pedal force created by the driver should be about 600 N.

When replacing the clutch drive hydraulic booster to remove the hydraulic booster:

  • - release air from the auxiliary brake system drive circuit and other consumers through the valve on the receiver;
  • - remove the release spring of the clutch fork shaft lever, disconnect the pneumatic hydraulic booster air pipe, hydraulic hose and drain the fluid from the hydraulic drive system;
  • - unscrew the two bolts of the hydraulic booster and remove the booster with the rod.

To install a pneumatic hydraulic booster:

  • - align the mounting holes with the holes in the clutch housing and secure the booster with two bolts with spring washers;
  • - connect the hydraulic hose of the pneumatic hydraulic booster and the air pipeline;
  • - install the release spring of the clutch release fork shaft.

Pour brake fluid into the reservoir of the master cylinder and bleed the hydraulic system.

Check the tightness of the pipeline connections (leakage of brake fluid from the connections is not allowed), if necessary, eliminate the leakage by tightening or replacing individual elements of the connections.

Check and, if necessary, adjust the gap between the end face of the cover and the stroke limiter of the valve stem for switching on the gear divider.