A slack adjuster for use with a braking system which has an increased let-out length that enables the use of brake shoes having an increased thickness. The slack adjuster includes a dual spring and canister assembly, an external yoke trigger, or a combination of both the dual spring and canister assembly and the external yoke trigger. A method of retrofitting a truck-mounted brake system is provided, in which the slack adjuster is positioned within the brake system in order to increase the let-out length while maintaining a predetermined spatial envelope within the brake system. The slack adjuster has an increased let-out length enabling the use of thicker brake shoes without requiring modification of the interacting components of the truck mounted brake system since the overall size of the slack adjuster remains the same.

A brake apparatus for a vehicle may include: a pair of screw bars located in a caliper body; a pair of nut parts configured to cover outsides of the respective screw bars, engaged with the respective screw bars, and selectively moved toward a brake pad or moved to an opposite side of the brake pad; a pair of piston parts moved with the nut parts, and configured to apply pressure to the brake pad when pressed by the nut parts or remove the pressure applied to the brake pad when a pressing of the nut parts is removed; an elastic spring installed on each of the piston parts, and configured to apply an elastic restoring force to cause the piston part to return to an original position; and a spring retainer mounted on each of the piston parts, and brought into contact with the elastic spring.

A brake apparatus for a vehicle may include: a pair of screw bars located in a caliper body; a pair of nut parts configured to cover outsides of the respective screw bars, engaged with the respective screw bars, and selectively moved toward a brake pad or moved to an opposite side of the brake pad; a pair of piston parts moved with the nut parts, and configured to apply pressure to the brake pad when pressed by the nut parts or remove the pressure applied to the brake pad when a pressing of the nut parts is removed; an elastic spring installed on each of the piston parts, and configured to apply an elastic restoring force to cause the piston part to return to an original position; and a spring retainer mounted on each of the piston parts, and brought into contact with the elastic spring.

A drum brake apparatus includes: a housing; a main braking unit disposed on a first portion of the housing, and the main braking unit configured to be, during main braking, driven by a hydraulic pressure and pressing a shoe; a parking braking unit disposed on a second portion of the housing, the parking braking unit configured to be, during parking braking, driven by an electromotive force of an actuator and pressing the shoe; a first locking member configured to couple the housing to one surface of a back plate; and a second locking member configured to couple the actuator to the housing on another surface side of the back plate.

A method for operating a parking brake which has an actuator with an actuating element and an electric motor, the electric motor is operatively connected to the actuating element in order to displace the latter, the electric motor is actuated in order to displace the actuating element by a predefined movement travel, and an actual movement travel of the actuating element is monitored in order to actuate the electric motor. The method includes determining the actual movement travel of the actuating element in a manner which is dependent on a motor current and/or a motor voltage of the electric motor.

A method for operating a parking brake which has an actuator with an actuating element and an electric motor, the electric motor is operatively connected to the actuating element in order to displace the latter, the electric motor is actuated in order to displace the actuating element by a predefined movement travel, and an actual movement travel of the actuating element is monitored in order to actuate the electric motor. The method includes determining the actual movement travel of the actuating element in a manner which is dependent on a motor current and/or a motor voltage of the electric motor.

A brake system and a method of controlling a brake system. The method may include indirectly estimating an air gap between a brake friction member and a brake pad assembly based on a position signal from a position sensor that detects cycling of the friction brake and a further signal indicative of an amount of brake force used to engage the brake pad assembly with the brake friction member. The air gap may be adjusted when an estimated air gap differs from a desired air gap.

A brake system and a method of controlling a brake system. The method may include indirectly estimating an air gap between a brake friction member and a brake pad assembly based on a position signal from a position sensor that detects cycling of the friction brake and a further signal indicative of an amount of brake force used to engage the brake pad assembly with the brake friction member. The air gap may be adjusted when an estimated air gap differs from a desired air gap.

A vented cap for a main spring housing of a slack adjuster including an inner portion having an inner seal surface configured for cooperating with an elongated rod member and an outer seal surface configured for cooperating with a sidewall located at an end portion of the main spring housing. The vented end cap includes at least one opening configured to allow fluid and/or contaminants trapped within the slack adjuster and/or the end cap to drain therethrough. Various seals and/or drainage openings can also be provided along the slack adjuster to prevent the entrance of and/or allow for drainage of fluid/contaminants from the slack adjuster. A method for preventing the accumulation of fluid and/or contaminants within a slack adjuster and for protecting a critical operating area of the slack adjuster is also provided.

A vented cap for a main spring housing of a slack adjuster including an inner portion having an inner seal surface configured for cooperating with an elongated rod member and an outer seal surface configured for cooperating with a sidewall located at an end portion of the main spring housing. The vented end cap includes at least one opening configured to allow fluid and/or contaminants trapped within the slack adjuster and/or the end cap to drain therethrough. Various seals and/or drainage openings can also be provided along the slack adjuster to prevent the entrance of and/or allow for drainage of fluid/contaminants from the slack adjuster. A method for preventing the accumulation of fluid and/or contaminants within a slack adjuster and for protecting a critical operating area of the slack adjuster is also provided.