Process of assembly of master cylinder

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 (al 1 ) of the master cylinder with at least one spring (r 2 ) 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 (r 2 ) is free and in that the method comprises at least the following step: installation of a temporary retaining pin (g 1 ) in an access hole (tr 1 ) located on the periphery of the master cylinder (MC) so that the pin (g 1 ) emerges inside the barrel (al 1 ) between the mouth (MCe) of the barrel and either the primary or the secondary piston (pp or ps).

2. Method for fitting/removing a master cylinder according to claim 1 , characterized in that the said retaining pin (g 1 ) is installed temporarily in the said access hole (tr 1 ) while the master cylinder is being fitted to a braking assistance servo unit.

3. 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.

4. 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.

5. 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 (g 1 ) emerges inside the barrel (al 1 ) between the mouth (MCe) of the barrel and the secondary piston (ps).

6. Method for fitting/removing a master cylinder according to claim 5 , characterized in that the pin is made of rigid plastic.

7. 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 (ap 1 ) so as to allow its insertion in the said hole with friction contact on the portion of the access hole.

8. 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 (ap 1 ) 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.

9. 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 (g 1 ) includes a threaded portion allowing the pin to be screwed into the thread of the said access hole.

10. Method for fitting/removing a master cylinder according to claim 6 , characterized in that the pin (g 1 ) includes a tapered end (ge) allowing its insertion in the access hole.

11. 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.

12. 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.

13. 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 (g 1 ) emerges inside the barrel (al 1 ) between the mouth (MCe) of the barrel and the secondary piston (ps).

14. Method for fitting/removing a master cylinder according to claim 1 , characterized in that the pin is made of rigid plastic.

15. 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 (ap 1 ) so as to allow its insertion in the said hole with friction contact on the portion of the access hole.

16. 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 (ap 1 ) 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.

17. 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 (g 1 ) includes a threaded portion allowing the pin to be screwed into the thread of the said access hole.

18. Method for fitting/removing a master cylinder according to claim 1 , characterized in that the pin (g 1 ) includes a tapered end (ge) allowing its insertion in the access hole.

19. 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.

20. 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.