Remote compensation valves for a master cylinder in a brake system

A brake system having a brake booster responsive to an input force for developing an output force to move pistons in a master cylinder and immediately pressurize fluid therein which is communicated through remote first and second compensation valves to activate wheel brakes of a vehicle and effect a brake application, each of said remote first and second compensation valves comprising:

• a housing having a bore therein with an inlet port, a compensation port and an outlet port;
• a piston located in said bore having a first land separated from a second land by a groove, said second land separating said inlet port from said compensation port and said outlet port, said piston having a axial bore therein that extends from a first end to a second end and at least one radial bore that extends from said axial bore to said groove to connect said inlet port with said groove, said axial bore having a first diameter separated from a second diameter by a shoulder;
• a tilt valve located in said compensation port having a pin that extends through said bore in said housing and into said groove in said piston;
• a poppet valve having a stem located in said first diameter and a head attached to said stem and located in said second diameter of said axial bore of said piston;
• first spring means for urging said head of said poppet valve toward said shoulder on said piston;
• second spring means for urging said piston toward said inlet port to bring said first land into engagement with said pin on said tilt valve and initiate communication of fluid between a source of fluid and said bore through said compensation port;
• and
• a movable stop pin retained in said housing with a first end external to said housing and a second end extending into said axial bore of said piston, said second spring means urging a annular flange on said movable stop pin into engagement with said housing to define an operational position whereby movement of said piston by pressurized fluid from the master cylinder in overcoming said second spring moves said first land out of engagement with said tilt valve pin to allow said tilt valve to interrupt communication of fluid from said source through said compensation port and bring said stem into engagement with said second end of said movable stop pin to initiate communication of pressurized fluid from said inlet port to the outlet port to effect a brake application, said second spring means in the absence of said pressurized fluid moving said piston to bring said first land into engagement with said tilt valve and reestablish communication of fluid from said source through said compensation port and move said stem out of engagement with said second end of the movable stop pin to allow said first spring means to seat said head on said shoulder in said axial bore and interrupt communication from the inlet port to said outlet port, said movable stop responding to a manual input force applied to said first end to overcome said second spring means and bring said second end into engagement with said stem of said poppet valve and move said head off said shoulder to establish fluid communication between said inlet port and said compensation port.