One problem related to steering failed has been reported for the 2006 Ford F-150. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2006 Ford F-150 based on all problems reported for the 2006 F-150.
Noticed steering wheel very hard to turn. Checked power steering fluid which was ok. Researched problem online and found dozens of similar complaints reported on Ford customer forums and elsewhere online mentioning that the u-joint(s) on the lower steering shaft possibly rust and corrode and become very stiff. When turning corners wheel does not readily recenter itself. Fearful that steering joints could fail, seize or break resulting in a complete loss of steering and serious injury or death. Saw that Ford redesigned the steering shaft after 2006 and the new Ford part looks much different than the original shaft in my 2006 truck. Sprayed some penetrating oil on both u-joints yesterday and steering was noticeably much easier within 5 minutes. Then sprayed some liquid wrench lubricating oil (lightweight aerosol oil) on both joints and drove the truck. Steering was like new and steering wheel easy to turn. Do not know however if this "oiling fix" will last. Ford is aware of this issue as they redesigned the steering shaft/u-joints and had hundreds of complaints. Defect in design of critical steering component, Ford is aware and redesigned steering shaft and u-joints. Note: other customers with non-Ford vehicles and Ford vehicles other than the F-150 have reported numerous similar complaints.