The longer I work on cars, the more I learn to go for the simple things first...
This weekend I worked in a Quite Garage, lifted the front end, and I believe/hope that I have "traced" the "popping" steering noise down.
OK - I've read quite a bit about the Lower Steering Shaft Universal Joint binding and/or getting very sloppy. This u-joint attaches to the input shaft of the Steering Rack and is covered by a rubber boot (so you can't physically see the u-joint).
In short, the Explorer Steering Wheel transmits ALL of it's L/R motions through a tiny universal joint that hooks directly up to the Steering Rack (rack and pinion).
Take into account that the steering universal joint is in the engine compartment (hot environment) and you can see how after 10 yrs they can go bad (dry up their lubricant grease) - despite being covered by a rubber "boot."
So I grabbed the lower steering shaft, slightly above the rubber boot, and when I pulled up/down and left/right I felt about 3/8 - 1/2 inch of play - followed by a distinctive "pop" - the same pop as I HEAR and FEEL through the steering wheel!
I am guessing that at a minimum, I should not be able to feel any l/r up/down play in the lower steering universal joint - Correct??????????
So, with this in mind, I am going to start with replacing the lower steering shaft (that connects to the r&P) first. I want to purchase a new one - so I'll start w/ FORD - and siut down when placing that call to the Parts Department.
I'll report back and let everyone how this turns out -
Regards,
Fast Dave
PS to Patrick:
With the truck in the air, I grabbed both the Left and Right side CV Axel's and could not detect any up/down of forward/reverse play or slop.
Also, when the truck was in the air, I took turns turning the front wheels full lock, and when they were full lock I rotated - by hand - the front wheels as if they were traveling down the road. While doing this "test," I could not hear/feel anything out of the ordinary from the CV Axel's or Wheel Bearings.