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DESCRIPTION AND MODIFICATIONS
VACUUM / HYDRAULIC SYSTEM Description
The service system consists of a vertically split hydraulic system with vacuum servo assistance to all wheels. The secondary system is the unfailed half of the system i.e. full braking on one axle.
The parking brake is mechanically operated and acts on rear wheels only. The system incorporates the following features.
Brake Assemblies - Self adjusting wheel cylinders with manual override facility loir brake drum removal and initial adjustment. Backptates incorporate lining inspection holes and adjuster notes which are sealed by means of rubber grommets-
Vacuum System - 3/8in. Bundy tubing is employed throughout. Vacuum is produced by manifold depression on petrol engines and by exhauster on diesei engines. The vacuum reservoir has a capacity of 5 litres. Girling vacuum servos are directly mounted to a Girling tandem master cylinder. The types used will be found in Data.
The system incorporates a vacuum gauge and a low vacuum warning tight, the latter doubling as a handbrake warning light also.
Hydraulic System - 3/16 in. Bundy tubing is employed throughout. The tandem master cylinder with its direct mounted fluid reservoir is split vertically, the secondary cylinder operating the front brakes and the primary cylinder operat'ng the rear brakes.
A low fluid level indicator is located in the reservoir cap and this has the facility for manually testing its integrity. The integrity of the low fluid level warning light, mounted on the instrument panel, is checked each time a cab door is opened.
Rear wheel braking is controlled
by a load sensing valve mounted on the rear axle.
The setting instructions for this valve are extremely important and will be found in sub-section M 241.
Handbrake — the handbrake acting on duo-servo type rear brakes through cable linkage and axle mounted compensator is extremely efficient when correctly adjusted . A warning light in the cab indicates when the handbrake is not fully released.
Fig. 1 Diagrammatic Brake System (Vac/hyd)