Capt.magoo,
In my Boeing manuals I couldn't find any information about a warm up time needed before using the brakes otherwise they won't work.Although -since we don't do taxying from the right side in 737-I don't use the brakes too much during taxi but most of the times the brakes are already warm from the previous landing.
In the experience I stated was contraverse what you said I applied not too much pressure and the responce was quick instead of lacking and hard.It was the first time experience of an inexperienced copilot which tought me a valuable lesson.
If you please guide me where I can reach the information you provided I can add some to my knowledge.
Regards.WING737