Massey Ferguson T165 – TRANS1: High Pressure Brake System Charging Too Often DYNA 6 (TRANS1)

The high-pressure brake circuit is losing hydraulic pressure much faster than normal, causing the hydraulic pump and charging valve to cycle on and off (recharge the system) more frequently than the programmed threshold.

• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• Interim Tier 4 (2012-2015)
• 5400 Series
• 6400 Series
• 6600 Series
• 6614
• 6615
• 6616
• 6700 Series
• 7400 Series
• 7465
• 7475
• 7480
• 7495
• 7600 Series
• 7700 Series
• 8600 Series
• 8700 Series

1. 1

   Test the Brake Accumulator: Check the nitrogen pre-charge pressure of the high-pressure brake accumulator. If the accumulator is 'flat' (has lost its nitrogen charge) or the diaphragm is ruptured, it cannot store pressurized fluid, causing the pump to cycle constantly.

2. 2

   Inspect the Brake Pressure Sensor (Sensor X495): Check the sensor and its wiring harness for open circuits, short circuits to +12V, or erratic signals.

3. 3

   Check for Hydraulic Leaks: Inspect the brake valve block and brake piston seals for internal bypassing/leaks that would cause the system to lose pressure rapidly without the brakes being applied.

1. 1

   Depressurize the System

   Turn off the tractor engine. Pump the brake pedals repeatedly until they feel completely hard. This safely discharges any remaining hydraulic pressure in the brake accumulator.

2. 2

   Locate Components

   Locate the high-pressure brake accumulator and the brake pressure sensor (X495) on the brake valve block.

3. 3

   Replace the Accumulator (if faulty)

   Unscrew the old accumulator from the valve block. Lubricate the O-rings on the new accumulator and thread it into place. Important Safety Note: Replacement accumulators are sometimes shipped fully discharged for air freight safety and must be recharged with nitrogen to the OEM specified pressure using specialized equipment before installation.

4. 4

   Replace the Sensor (if faulty)

   Disconnect the wiring harness, unthread the old sensor, and install the new one.

5. 5

   Bleed the Brakes

   Bleed the tractor's brake system according to the OEM service manual to remove any introduced air.

6. 6

   Clear Codes

   Connect a diagnostic tool to the TRANS1 module, clear the T165 fault code, and test drive the tractor to verify the brake charging cycle has returned to normal intervals.