Fig. 238. Prorolling of a hydrodrive of coupling (an arrow the place of putting on of a rubber hose on the valve is shown): 1 — a hose; 2 — рожковый a key for отворачивания the prorolling valve

Removal of air from a coupling hydrodrive is carried out similarly to removal of air from brake system. The prorolling valve is nearby from a junction of the engine with a transmission (fig. 238, an arrow).

Air should be deleted from a coupling hydrodrive always when hydraulic pipelines have been disconnected or when air has otherwise appeared in hydraulic system. A sign of presence of air in hydraulic system is the slowed down returning of the pressed pedal of coupling or невозвращение it at all.