Technician Handbook ! 302 Manual Transmissions & Transaxles Master Cylinder When force is applied to the pushrod, the piston displaces hydraulic fluid in chamber A of the master cylinder (as shown in the illustration above). During initial piston travel, the compensating port in the master cylinder is closed by the piston. Further piston travel allows fluid to be displaced, transmitting force through the clutch line to the release cylinder located at the transmission. When the pushrod is released, the piston is returned to its initial position by a spring. With the compensating port open, pressure in chamber A equalizes with the reservoir.
If the compensating port is blocked, any expansion of the fluid due to heat could cause pressure in chamber A to increase. With normal clutch wear, this condition may eventually cause the clutch to slip. 16 Technical Training