Power Brake Unit

New low-pedal power brake units are available either as a Regular Production Operation or a dealer-installed accessory.

The new power brake units are functionally identical with the low-pedal units which were offered in 1958. The new units, however, use the regular production brake pedal and hydraulic master cylinder (Fig. 6). The vacuum power component is installed between the dash and the master cylinder, and the only regular production part replaced is the push rod from the pedal to the master cylinder. Since the vacuum power unit mounts on the same dash mounting points as the hydraulic master cylinder, the installation of the accessory or transfer of the optional unit can be accomplished with almost the same ease as changing a master cylinder.

While service procedures are revised, the valving of both types, Moraine and Bendix, remains the same as used in 1958. Both types are used interchangeably in the factory installation. There are no throw-away parts when installing the accessory package which contains the Bendix unit, and the hydraulic system need not be broken open.

The two different brake units may be readily identified, as the Bendix unit uses screws to hold the two halves of the power cylinder together while the Moraine unit has a lug and slot type of arrangement.

The brake pedal has two holes in it to permit its use with either standard or power brake systems.

While all brake service operations with the exception of the power brake overhaul procedures remain basically the same as on the 1958 models, the many

TRUCKS

Standard Brakes

The rear axles for 1/2 ton tucks are equipped with brake assemblies having larger lining areas. Each shoe and lining is 1/4-inch wider than the previous design.

Vacuum Power Brakes

The long stroke seven inch diameter Hydrovac units used in Series 50 and 60 production, and RPO for series 40 models, have undergone a number of minor structural changes to improve operation. In addition, a valve change has been made which increases vacuum assistance in the braking range most frequently used.

The control valve piston, is redesigned to increase power assistance as much as 75 percent within the braking range most commonly used. However, since the vacuum piston and hydraulic slave piston dimensions have not change, the maximum power assist available is still 65 percent of the total braking force required.

Air Brakes

Series 50, 60, 70 and 80 models, using air-hydraulic or full air brakes, have a new air compressor mounting for use with Taskmaster engines. Replacing the stamped bracket, the new cast malleable iron support attaches firmly to bosses on the engine cylinder head and intake manifold.

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