CLAAS Id7625h / 7625h (406) – TR2 (A57-2): High-pressure brake accumulator inflates too often (leak on energy reserve)

The system detects that the high-pressure braking circuit has been forced to reinflate at least twice in less than 10 minutes without any physical action on the brake pedals. This indicates a pressure loss in the rear brake circuit, meaning there is a leak in the energy reserve (the accumulator is losing its charge or hydraulic fluid is leaking from the circuit).

• Arion 410-430
• Arion 510-640
• Axion 800
• Axion 810-850
• Axion 960

1. 1

   Visually inspect the entire hydraulic braking circuit (valves, pipes, selectors, and fittings) for external leaks

2. 2

   Verify that there is no air trapped in the braking circuit by bleeding the system

3. 3

   Test the left-hand (CCN Z126) and right-hand (CCN Z127) brake pedal switches to ensure proper signals and that pedals return fully to their upper stops

4. 4

   Test the high-pressure braking pressure sensor (CCN B233 or B368) and solenoid valve (CCN Y329) for accurate readings and pressure holding

5. 5

   Check the rear service brake pressure accumulator (CCN 5016 or 5063) for a torn internal diaphragm or lost nitrogen gas charge

1. 1

   Depressurize the System

   Safely relieve hydraulic pressure from the braking circuit using the braking system decompression screw (CCN 6062) before opening any lines.

2. 2

   Bleed and Retest

   Bleed the brake lines. If the fault clears and the accumulator stops cycling, the issue was air in the lines.

3. 3

   Address Leaks

   If external leaks are found at the solenoid valve (Y329) or hydraulic lines, replace the damaged O-rings, fittings, or lines.

4. 4

   Replace Faulty Switches/Sensors

   If diagnostic tests show erratic readings from the brake pedal switches (Z126/Z127) or the pressure sensor (B233/B368), replace the faulty electronic component and recalibrate the pedals via the CLAAS Diagnostic System (CDS).

5. 5

   Replace the Accumulator

   If the circuit is sealed but the system still loses pressure rapidly, the accumulator's internal diaphragm is likely ruptured (often throwing a related code like Id7627h/408). Remove the faulty accumulator (CCN 5016/5063) and install a new pre-charged OEM brake accumulator.

6. 6

   Clear Codes

   Use the CDS tool to clear the TR2 module codes and test drive the tractor to ensure the accumulator does not recharge without pedal input.