High-Pressure Hydraulic Braking Accumulator and Mineral Oil System Failure
SeriousBrakesThe SZ generation employs a complex Citroën-licensed dual-circuit hydraulic system operating at over 2,000 psi to power the braking system and rear self-levelling suspension. The nitrogen-charged brake accumulator spheres lose pressure over 5 to 8 years, resulting in a rock-hard brake pedal, prolonged pump cycle times, and reduced reserve braking capacity. If brake fluid types are mistakenly interchanged (such as adding standard DOT fluid into mineral oil systems), internal rubber seals dissolve, triggering catastrophic system failure.
Brake warning lights illuminate or take over 30 seconds to extinguish after starting, Hard brake pedal feel accompanied by severely reduced braking assistance, Rapid clicking noise from engine-driven hydraulic pumps under braking, Mineral hydraulic fluid puddling beneath engine bay or transmission tunnel
- Perform the standard accumulator discharge test by pumping the pedal 40 times with ignition on
- Inspect the hydraulic distribution valves and brake accumulators for fluid leaks
- Verify in maintenance history that only approved mineral fluid (RR363 or Castrol HSMO) has been used
- Check the time taken for low-pressure warning lights to extinguish from a stone cold start