|Quoting MD88Captain (Reply 2):|
Often a delay in gear retraction is used to cool the brakes and tires after a prolonged taxi on heavy weight aircraft.
|Quoting Fr8mech (Reply 7):|
There is also a chance tat a brake was deferred. The crew must leave the gear down in order to allow the wheel to come to a stop.
|Quoting 474218 (Reply 8):|
When the gear handle is selected to the up position, hydraulic pressure is routed to brakes, which stops the wheel rotation.