As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT BRAKE FEELS SPONGY ON BOTH PILOTS PEDALS. PUMPING THE PEDAL DOES NOT BRING THE PRESSURE BACK. ACCESSED ALL TUBING CONNECTIONS TO ALL LEFT BRAKE COMPONENTS, ALL TUBING RUNS CHECKED FOR SECURITY AND LEAKAGE, ALL CHECKED GOOD. VERIFIED PROPER RESERVOIR SERVICE, REPLACED LEFT BRAKE WITH NEW UNIT AND PERFORMED A SATISFACTORY BLEED, LEAK AND OPS CHECK IAW EA500 MM 32-41-15.