Abstract: The pistons, valves and failure warning switch mechanism contained within the bore of a master cylinder are preassembled in a container in kit form. The container provides for correct orientation of the parts in the master cylinder bore so that the failure warning switch actuating mechanism is properly aligned with the failure warning switch. The container is a tube of suitable material having a bore with the various internal parts of the master cylinder preassembled in it. Folding locating arms are attached near the forward end of the tube and normally held in a folded position by a cap and plug which closes the forward tube end. When the kit is ready to be used, the cap and plug are removed, the arms are unfolded, and the arm ends are aligned so that they extend through the bolt holes in the mounting ears of the master cylinder body. The tube bore is in alignment with the rear end of the master cylinder bore.

Abstract: A combination proportioner and a shuttle piston which when moved actuates a brake pressure loss warning switch. A proportioner piston has a spring preload which must be overcome by rear brake supply pressure before the proportioner is actuated. Upon brake release the lips of the switch actuating piston proportioner seal act as a valve to relieve rear brake pressure to the pressure at which the proportioner began to operate. The proportioner is deactivated upon front brake system pressure loss. The proportioner mechanism is so assembled that it can be utilized as an original installation or as a replacement module. In an installation where no proportioning action is required, the shuttle piston and head nut are installed without a proportioning valve. When a proportioning valve is required, a head nut with the proportioning mechanism preassembled therein is installed.

Abstract: A dual master cylinder has a secondary piston which when actuated pressurizes fluid in two secondary chamber sections with one chamber section increasing pressure at a faster rate than the other as the piston is stroked. The piston has passage means therein interconnecting the two chamber sections, a proportioning valve mechanism in the passage means acting to proportion fluid pressure from the one chamber section to the other chamber section after a predetermined pressure differential exists in the two chamber sections. A shuttle piston also mounted in the secondary piston is responsive to pressure generated in the one secondary chamber section and in the primary pressurizing chamber between the primary and secondary master cylinder pistons.

Abstract: A vehicle brake booster and master cylinder assembly has a vacuum suspended booster section which is controlled by movement of the vehicle brake pedal. A hydraulic booster section is in series with the vacuum suspended booster section, and a master cylinder unit is in series with the hydraulic booster section. The assembly is so arranged that in normal operation the vehicle operator obtains booster brake actuating pressures by operation of the vacuum suspended booster which acts through the hydraulic booster mechanism without operating the hydraulic booster. When greater brake actuating pressures are required, as indicated by increased brake pedal force exerted by the operator, the vacuum booster reaches its limit or run-out condition and the hydraulic booster is operated so as to continue the increase in master cylinder output pressure.