On a scania articulated unit what could cause the break pads on all 4 corners to wear differently?

Question

the two front corners the pads have 62% and 52% ,the two rear corners have 23% and 29%. what could be causeing this and when would it be advisable to replace the pads?

Answer 1

warn guide pins or bushings  nissalignment ??  will really need to look at it  sorry