Massey Ferguson 14.03.06 – TRANS1: High Pressure Brake System Charging Too Often DYNA 6

This condition occurs when the high-pressure hydraulic brake circuit loses pressure too rapidly, forcing the brake charging valve and hydraulic pump to cycle (charge) constantly to maintain safe braking pressure. The most common culprit is a failed brake accumulator (which has lost its nitrogen gas pre-charge) or an internal hydraulic leak within the brake valve or brake pistons.

• 7714
• 7715
• 7715S
• 7716
• 7716S
• 7718
• 7718S
• 7719
• 7720
• 7720S
• 7722
• 7722S
• 7724
• 7724S
• 7726
• 7726S
• Tier 4 (2015-2021)
• 5700 S / SL Series
• 5709SL
• 5710SL
• 5711SL
• 5712SL
• 5713SL
• 6400 Series
• 6465
• 6475
• 6480
• 6600 Series
• 6614
• 6615
• 6616
• 6700 S Series
• 6713 S
• 6714 S
• 6715 S
• 6716 S
• 6718 S
• 7400 Series
• 7465
• 7475
• 7480
• 7495
• 7600 Series
• 7614
• 7615
• 7618
• 7619
• 7620
• 7624
• 7700 S Series

1. 1

   Accumulator Pre-charge Check: Test the accumulator's nitrogen pre-charge pressure (typically around 9 Bar / 130 PSI, though this varies slightly by exact model) to check for a ruptured diaphragm or leaked nitrogen gas.

2. 2

   Hydraulic Leak Down Test: Check for internal leaks in the brake valve or brake piston seals. If the accumulator is good but pressure drops rapidly without pedal input, fluid is bypassing a seal.

3. 3

   Sensor Verification: Verify the Brake Pressure Sensor is outputting the correct voltage/pressure readings to the TRANS1 module, ensuring the system isn't 'ghost charging' due to a faulty sensor reading.

1. 1

   Depressurize the System

   CRITICAL SAFETY STEP. Turn the engine off. Pump the service brake pedals repeatedly until the accumulator is completely discharged and the pedal feels completely stiff.

2. 2

   Remove the Accumulator

   Locate the high-pressure brake accumulator (usually a black or green steel sphere/bottle threaded into the brake valve block). Disconnect the hydraulic lines, taking care to catch residual fluid.

3. 3

   Replace or Recharge

   If the accumulator is serviceable, have it resealed and recharged with nitrogen gas by a qualified hydraulic shop. Most modern diaphragm accumulators are sealed units and must be replaced entirely.

4. 4

   Address Internal Leaks (If Applicable)

   If the accumulator was not the issue, remove and rebuild the brake valve block or replace the internal brake piston seals.

5. 5

   Reinstall and Bleed

   Install the new accumulator. Start the tractor and allow the brake charging valve to cycle and charge the accumulators to cut-out pressure. Bleed the brake system to remove any trapped air.