Massey Ferguson 14.00.02 – TRANS1: High Pressure Brake System Pressure Too Low

The tractor's onboard diagnostic system has detected that the pressure in the high-pressure pneumatic/hydraulic brake circuit has dropped below the required operational threshold (normal operating pressure is around 18.5 bar; warnings typically trigger if it drops below 4 bar). When this accumulated brake pressure is too low, the transmission will actively prevent engagement for safety reasons, and the ParkLock system may be affected or locked.

• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7720S
• 7722
• 7722S
• 7724
• 7724S
• 7726
• 7726S
• Tier 4 (2015-2021)
• 5400 Series
• 5600 Series
• 5700 S Series
• 5713 S Dyna-6
• 6400 Series
• 6600 Series
• 6700 S Series
• 6480
• 6713 S Dyna-6
• 7600 Series
• 7700 S Series
• 7624 Dyna-6
• 7726 S Dyna-6
• 8600 Series
• 8700 Series

1. 1

   Verify the hydraulic fluid levels and quality, inspect the hydraulic pump operation, and check related fuses to ensure the system is capable of generating pressure.

2. 2

   Check the condition of the air connection couplers attached to any implements, as well as the tractor's pneumatic braking system lines, for obvious leaks.

3. 3

   Inspect the wiring harness and connector to the brake pressure sensor for damage, corrosion, or an open circuit (which can falsely report low pressure).

4. 4

   Check if the high-pressure brake accumulator (diaphragm accumulator) has ruptured or lost its internal nitrogen pre-charge, which prevents the system from building and holding pressure.

1. 1

   Preparation

   Position the tractor on flat, level ground. Chock the wheels to prevent rolling, as the ParkLock and braking systems are currently compromised.

2. 2

   Depressurize the System

   Before removing any hydraulic or pneumatic components, safely relieve all residual pressure in the high-pressure brake system to prevent injury.

3. 3

   Replace the Faulty Component

   If the Pressure Sensor is faulty: Disconnect the electrical harness, unthread the old sensor from the brake valve block, install the new sensor, and reconnect the harness. If the Accumulator is faulty: Unthread the failed diaphragm accumulator. Install the new accumulator (ensure it is a pre-charged unit, as replacement accumulators must be properly charged with nitrogen before use).

4. 4

   Fluid & Bleed

   Top up the hydraulic fluid to the correct level. Bleed the brake system if air was introduced into the hydraulic side of the circuit during component replacement.

5. 5

   Transmission Calibration

   After repairing transmission/brake components on a Dyna-6, a calibration is highly recommended. Warm up the transmission oil so the temperature is between 35°C (95°F) and 45°C (113°F) (verifiable via "diagnostic screen 1" on the Dash Control Center), and run the Dyna-6 calibration procedure.