B757-200
Flight Crew Air Transport Pilot (ATP)
Aircraft Equipment Problem Less Severe; Inflight Event / Encounter Weather / Turbulence
Air Traffic Control Provided Assistance; Flight Crew Overcame Equipment Problem
Aircraft; Weather
Shortly after level off at FL380; crew selected Airborne Weather Radar 'On' as convective weather was forecast along our flight planned route.  'WX FAIL' immediately appeared on the Navigation Display (ND) and no weather radar returns were present; indicating a failure of the Airborne Weather Radar system.  Crew consulted the aircraft QRH; Systems Manual; Pilot Handbook; Pilot Handbook Supplement; Flight Operations Manual; and Minimum Equipment List (MEL).  None offered guidance for this failure.  Crew then consulted the company Dispatcher and alerted Center.  Crew asked Center if there were any other ZZZ-bound [Company] aircraft in the area that we could follow. Center vectored us into 20 NM trail of [Company Flight].  Crew established communication with [the flight] on Company frequency using our secondary radio. [They] then led us safely to ZZZ; deviating around weather when necessary.
After losing weather radar; B757 flight crew established communication with a Company aircraft enroute to the same destination and followed them through weather to the airport.