It reminds me (NB: NO suggestion this was the cause!) of an engineer who taxied a 727 onto stand in TXL but forgot to put the hydraulic pumps on.......................it took a while to get the jetty out of the wing.
Was that a -235 model by any chance?
The 727 has a famous design issue where you need to open a hydraulic interconnect under some circumstances to get normal braking. There are pneumatic brakes but by the time you find that yellow handle it's usually all over but the shouting.