Many years ago I flew for a 737-200 airline operating to small Pacific atolls and islands. Some runways were built of crushed coral with lengths varying from as low as 5000 feet to others like Guam for instance, of 10,000 ft. Good airmanship dictated a walk-around after each landing and in particular to carefully assess the brakes for overheating where moderate to hard braking may have taken place.
A crew flew one of the aircraft, where it had undergone scheduled servicing, from Hong Kong via Taipei to Guam where I took it over for the next sectors from Guam to Ponape and to final destination Nauru.
In small airlines you get to know the pilots renowned for their heavy braking technique since the brakes are usually much hotter than when other pilots land. Hence the careful assessment of brake temperature during the walk around . At Guam I waved my hand carefully in the vicinity of the brakes after taking over the aircraft from a known heavy braker. One set of wheel brakes were noticeable cooler than the other. I put this down to the long runway and the roll-through required to turn off at the far end and uneven foot pedal pressure by the pilot.
We departed Guam for the 1.3 hour flight to Ponape where the runway was wet coral and 5400 ft long. This required an accurate touch down speed (none of this extra for Mum and the kids). During refuelling I did the walk around and waved my hand between the wheels to assess the heat. One side was quite warm (I did not risk a burnt hand by actually touching the brake area) while the other was cool. I thought maybe the cool side had gone through puddles of water on the runway. But I had my suspicions. We carried an engineer but he was not concerned. We had a 45 minute turn around and next landing was on the 5600 ft runway at Nauru where the aircraft was to stay overnight. Again I checked both sets of brakes and as expected one side was hot but the other side cold There had been no pull to one side during the landing run probably because full reverse was used and brakes eased on around 80 knots.
I wrote up the brake anomaly in the maintenance release and went to the pub. The engineer examined the brakes and found the outboard brake on the right set of wheels was disconnected - probably at Hong Kong during servicing. That is why the hand waving found the brakes that side were cool. It was fortunate that we had not experienced a high speed rejected take off requiring max braking on all brakes or we might have finished up in the ocean at some of the destinations.