# US 8,146,232 B2 · Process of assembly of master cylinder > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,146,232 B2 - Document ID: US8146232B2 - Status: Granted - Kind: B2 - Application number: 12/030,602 - Filed: 2008-02-13 - Published: 2008-08-21 - Granted: 2012-04-03 - Earliest claimed: 2007-02-16 - Assignees: Robert Bosch GmbH - Inventors: Philippe Bourlon; Lionel Bourgois - Web page: https://patentgrep.com/patent/US8146232B2 ## CPC - B60T 11/20: Tandem, side-by-side, or other multiple master cylinder units - Y10T 29/49902: by manipulating aligning means - Y10T 29/53: Means to assemble or disassemble - B60T: VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL (electrodynamic brake systems for vehicle, in general B60L; brakes per se, i.e. devices where braking effect occurs, including ultimate brake actuators, F16D); ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES - Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION ## Abstract The invention relates to a method for fitting/removing a brake master cylinder (MC) of a motor vehicle providing the installation of a temporary retaining pin (g1) in an access hole (tr1) located on the periphery of the master cylinder (MC) so that the pin (g1) emerges inside the barrel (al1) between the mouth (MCe) of the barrel and either the primary or the secondary piston (pp or ps). ## Claims ### Claim 1 Method for fitting/removing a brake master cylinder (MC) which comprises a primary piston (pp) and a secondary piston (ps) which are mounted in a barrel (al1) of the master cylinder with at least one spring (r2) placed between the bottom (MCf) of the barrel and the secondary piston (ps) and having a function of pushing back the secondary piston (ps) and the primary piston (pp) toward the mouth (MCe) of the barrel, characterized in that the secondary spring (r2) is free and in that the method comprises at least the following step: installation of a temporary retaining pin (g1) in an access hole (tr1) located on the periphery of the master cylinder (MC) so that the pin (g1) emerges inside the barrel (al1) between the mouth (MCe) of the barrel and either the primary or the secondary piston (pp or ps). ### Claim 2 (depends on 1) Method for fitting/removing a master cylinder according to claim 1, characterized in that the said retaining pin (g1) is installed temporarily in the said access hole (tr1) while the master cylinder is being fitted to a braking assistance servo unit. ### Claim 3 (depends on 2) Method for fitting/removing a master cylinder according to claim 2, characterized in that the said access hole is a braking pressure communicating hole between the master cylinder and a hydraulic braking circuit, or a hole for supplying the master cylinder with brake fluid. ### Claim 4 (depends on 3) Method for fitting/removing a master cylinder according to claim 3, characterized in that the said access hole is a braking pressure communicating hole between the master cylinder and a hydraulic braking circuit. ### Claim 5 (depends on 4) Method for fitting/removing a master cylinder according to claim 4, characterized in that the said access hole is located between the secondary piston (ps) and the mouth (MCe) of the barrel, so that the pin (g1) emerges inside the barrel (al1) between the mouth (MCe) of the barrel and the secondary piston (ps). ### Claim 6 (depends on 5) Method for fitting/removing a master cylinder according to claim 5, characterized in that the pin is made of rigid plastic. ### Claim 7 (depends on 6) Method for fitting/removing a master cylinder according to claim 6, characterized in that the diameter of a portion (gg) of the pin is generally equal to the diameter of a portion of the access hole (ap1) so as to allow its insertion in the said hole with friction contact on the portion of the access hole. ### Claim 8 (depends on 6) Method for fitting/removing a master cylinder according to claim 6, characterized in that the diameter of a portion (gg) of the pin is less than that of a portion (ap1) of the access hole and includes, on its periphery, elements in the form of protuberances allowing a friction contact on the inside walls of the portion of the access hole. ### Claim 9 (depends on 6) Method for fitting/removing a master cylinder according to claim 6, characterized in that the access hole has a thread and in that the pin (g1) includes a threaded portion allowing the pin to be screwed into the thread of the said access hole. ### Claim 10 (depends on 6) Method for fitting/removing a master cylinder according to claim 6, characterized in that the pin (g1) includes a tapered end (ge) allowing its insertion in the access hole. ### Claim 11 (depends on 1) Method for fitting/removing a master cylinder according to claim 1, characterized in that the said access hole is a braking pressure communicating hole between the master cylinder and a hydraulic braking circuit, or a hole for supplying the master cylinder with brake fluid. ### Claim 12 (depends on 11) Method for fitting/removing a master cylinder according to claim 11, characterized in that the said access hole is a braking pressure communicating hole between the master cylinder and a hydraulic braking circuit. ### Claim 13 (depends on 12) Method for fitting/removing a master cylinder according to claim 12, characterized in that the said access hole is located between the secondary piston (ps) and the mouth (MCe) of the barrel, so that the pin (g1) emerges inside the barrel (al1) between the mouth (MCe) of the barrel and the secondary piston (ps). ### Claim 14 (depends on 1) Method for fitting/removing a master cylinder according to claim 1, characterized in that the pin is made of rigid plastic. ### Claim 15 (depends on 1) Method for fitting/removing a master cylinder according to claim 1, characterized in that the diameter of a portion (gg) of the pin is generally equal to the diameter of a portion of the access hole (ap1) so as to allow its insertion in the said hole with friction contact on the portion of the access hole. ### Claim 16 (depends on 1) Method for fitting/removing a master cylinder according to claim 1, characterized in that the diameter of a portion (gg) of the pin is less than that of a portion (ap1) of the access hole and includes, on its periphery, elements in the form of protuberances allowing a friction contact on inside walls of the portion of the access hole. ### Claim 17 (depends on 1) Method for fitting/removing a master cylinder according to claim 1, characterized in that the access hole has a thread and in that the pin (g1) includes a threaded portion allowing the pin to be screwed into the thread of the said access hole. ### Claim 18 (depends on 1) Method for fitting/removing a master cylinder according to claim 1, characterized in that the pin (g1) includes a tapered end (ge) allowing its insertion in the access hole. ### Claim 19 (depends on 1) Method for fitting/removing a master cylinder according to claim 1, characterized in that it includes, when fitting a master cylinder to a braking assistance servo unit, the following steps: installation of the primary and secondary pistons and their associated springs in the barrel of the master cylinder; compression of the springs; installation of the retaining pin; fitting of the master cylinder to a braking assistance servo unit; withdrawal of the retaining pin. ### Claim 20 (depends on 1) Method for fitting/removing a master cylinder according to claim 1, characterized in that it includes, when removing a master cylinder, the following steps: installation of the retaining pin; removal of the master cylinder from a braking assistance servo unit on which it is mounted.