What should a mechanic test for parking brake problem?
A useful test plan for parking brake problem verifies the operating state first, preserves scan evidence, and measures the competing brakes paths before any component is replaced.
Plausible causes
- Brake hydraulic, assist, friction, or ABS concern
- Hydraulic or assist fault
- Friction, hub, or wheel issue
Useful next checks
- Full brake/ABS module scan
- Hydraulic leak, fluid, hose, caliper, and assist inspection
- Pad/rotor measurement including thickness variation and hub runout
- Wheel temperature and residual-pressure comparison
Sources and method
This answer provides hypotheses and a verification plan, not a component verdict. Exact repair procedures require authoritative service information for the specific vehicle.
Brake Pulsation Diagnostic Guidelines · NHTSA / Audi