As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA FLIGHT 2002 DURING PUSHBACK, WHEN BRAKES APPLIED THE NR 1 HYDRAULIC PRESSURE DROPPED TO 1000 PSI. ROLL SPOILER CAUTION. MAINTENANCE REPLACED THE NR 1 SYSTEM UNLOADING VALVE AND ADJUSTED SPOILER DISCONNECT SENSOR. OPERATIONAL CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.