Innovative Braking and Controls Worldwide Boosted Master Cylinders hydraulically boosted straight bore, tandem, and two-stage master cylinders Versatile, High-performance Hydraulic Brake Actuators MICO, Inc. Form No. 84-460-007 Revised 2012-06-13 1

Why choose MICO? MICO, Inc. designs, manufactures and markets hydraulic components, controls, and brake systems primarily for off-road markets. We have manufacturing facilities in: • • • North Mankato, Minnesota U.S.A. Ontario, California U.S.A. Empalme, Sonora, Mexico Many of the world’s largest off-highway OEMs value the knowledgeable staff at MICO and work with us to make their products better. Our custom-engineered products are designed with the customer requirements as the primary driver. It is our intent to help customers build their systems with our expertise in hydraulic components, braking...

Operation of Boosted Master Cylinders Non-Actuated Position (Refer to Figure 1) The master cylinder section is not actuated and remains in the static condition without mechanical force being applied to the input piston (3). In the neutral (non-actuated) condition, uid from the vehicle’s hydraulic system ows unrestricted through the booster section. Hydraulic uid enters the inlet port (1), ows across piston lands (2) on input piston (3), through boost piston ow ports (4) into chamber (6), and exits the booster through outlet port (7). 1. The booster operates on the principle of restricting uid...

FIGURE 1 Callout Key (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15) Inlet Port Piston Lands Input Piston Flow Ports Boost Piston Chamber Outlet Port Booster Chamber Reaction Piston Spring Output Piston Master Cylinder Piston Internal Relief Valve Spring Spring FIGURE 2 FIGURE 3 MICO, Inc. Form No. 84-460-007 Revised 2012-06-13 5

Operation of Master Cylinder Sections Function of Residual Check Valves The cylinders listed in this catalog are available with or without a residual check valve. Be sure to use the proper cylinder for your application. Residual check valves are normally used in drum brake systems to hold a slight pressure (approximately 8-16 PSI) in the vehicle brake system while the brake pedal is released. This residual pressure is retained to air the lip of the cup seal in the wheel cylinder to prevent leakage and/or air ingestion into the brake system. Residual check valves are not used in disc brake systems....

Operation of Master Cylinder Sections (see pages 14 & 15) Operation of Tandem Master Cylinder (Refer to Figure 5) The tandem master cylinder was developed as a result of regulations governing brake systems on highway vehicles. Many off-road vehicles also use this type cylinder. These cylinders provide two independent master cylinder sections in a common housing. When the cylinder is at rest, the primary and secondary sections are directly communicated to the reservoirs, allowing, to a degree, purging of residual air and pressure equalization. Initial brake actuation forces front piston (1) to...

Operation of Master Cylinder Sections Operation of Straight Bore Master Cylinders (stem seal type) (see pages 12 & 13) (Refer to Figure 6) By eliminating the equalizing port normally found on master cylinders, this cylinder offers simplicity, ease of bleeding and versatility. The lack of a compensating port allows the cylinder to be used in a broad range of applications indiscriminative of volumetric output. input piston and to the vehicle pedal. This action provides the operator with modulated pedal feel proportional to the system pressure. With no input force on brake pedal the cylinder is...

Operation of Master Cylinder Sections Operation of Two-Stage Master Cylinders (see pages 16 & 17) (Refer to Figure 7) With no input force from the brake pedal, the cylinder uid is at reservoir pressure throughout. The relief valve piston (1) is closed, reservoir port (2) is open and high pressure piston (9) is open at seat (11). Initial brake pedal actuation forces the low pressure piston (5) to move the low pressure cup (3) past the reservoir port (2). Continued pedal movement causes uid in the low pressure bore (10) and high pressure bore (6) to become pressurized, forcing uid to exit the outlet...

Boosted Straight Bore Master Cylinders Style A Style B Style C (diaphragm reservoir) (dual ller caps) (single ller cap) FEATURES Provides natural pedal "feel" through hydraulic reaction Completely hydraulic - no vacuum or air assist required Residual valve used where required. Exhaust venting hole is normally in down position to prevent moisture contamination. NOTE: Dimensions vary slightly between units and are used for reference purposes only. Go to www.mico.com/service-literature/installation-drawing-search to view dimensional installation drawings. If the drawing is not available, contact...

Model No. 02-460-216 shown SPECIFICATIONS NOTE: While some model numbers may have identical specications, there may be differences in ttings, port sizes and ller plugs. Go to www.mico.com/service-literature/installation-drawing-search and enter the model number for more information. If the drawing is not available, contact MICO for more information. Style (see top of page 10) Brake Line Pressure (PSI) Master Cylinder Bore Diameter Master Cylinder Fluid Displacement Push Rod Force with Boosted Power Push Rod Force for 500 PSI without Boosted Power Booster Pressure Differential at Maximum Brake...

Boosted Straight Bore Master Cylinders (stem seal type) Style A Style B (dual ller caps) (single ller cap) FEATURES Provides natural pedal "feel" through hydraulic reaction Completely hydraulic - no vacuum or air assist required May be used for spring brake applications Easy to bleed Residual valve used where required. Exhaust venting hole is normally in down position to prevent moisture contamination. NOTE: Dimensions vary slightly between units and are used for reference purposes only. Go to www.mico.com/service-literature/installation-drawing-search to view dimensional installation drawings....