BENDIX SD-30-4250 manual II. Operation, Mechanical Operation, General

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SD-30-4250

COMPACT 500 INTEGRAL HYDRAULIC POWER STEERING GEAR FOR FORD MOTOR CO. CARGO VEHICLES

I. DESCRIPTION

The Compact 500 Hydraulic Power Steering gear is designed for heavy duty vehicles with front axle weight ratings of up to 15,000 lbs. It is an integral power steering gear incorporating the mechanical and hydraulic actuation and control components in a single cast housing which serves as the power cylinder.

The vehicle’s steering column is coupled to the gear at the input shaft which transmits steering effort through a recirculating ball screw and piston nut. The piston nut is an integral part of the power assist piston and also acts as a steering damper. The direction and degree of power assist is controlled by a rotary hydraulic valve which is integral to the input shaft and supplied by an engine driven hydraulic pump.

This valve design assures light, responsive steering while maintaining a mechanical connection between the steering column and the ball screw.

II.OPERATION

GENERAL

The C-500 integral power steering gear is composed both of mechanical steering components and hydraulic power assist components. Actual steering is accomplished mechanically. Effort applied at the vehicle’s steering wheel results in mechanical movement within the steering gear which causes the vehicle to change its direction of travel. The hydraulic power assist components function solely to reduce the effort required to turn the vehicle’s steering wheel. Loss of hydraulic power will in no way prevent the vehicle from being maneuvered mechanically, however greater effort will be required to turn the steering wheel.

MECHANICAL OPERATION

The turning effort exerted by the driver on the steering wheel is transmitted to the input shaft which is part of the ball screw assembly. The ball screw and piston nut function like

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