Wanting to put our 3 kayaks on the roof of our Expedition but were told to confirm the weight limit of the rack prior to purchasing the j cradles, etc. I can’t find this info ANYWHERE. Anyone using a Ford Expedition to haul their yaks? Are you using j-cradles or the center tower looking things? (yes, that is my technical term for them. LOL) TIA for any advice on this. 
call thule or yakima
They will be able to tell you. Car manufacturers tend to under rate the limit to limit their liability.
Racks
The Expedition factory racks are pretty flexible and I found that I had to cut the bolts of the kayak cradle to prevent them from denting the top of the truck while moving. (Carrying 17’ sea kayak)
Another thing to remember is that the Ford Expedition is one of the tallest trucks on the market. I had trouble getting my sea kayak on the roof. I eventually went to Thule base rack with Hullavator. Expensive but worth every penny. My back is very thankful, and my chiropractor misses me.
2005 Explorer Factory Racks
are rated 200 pounds. Not sure that is transferable to the Expedition.
look on the rack
every car that i have had has had the weight limit posted somewhere on the rack itself…as for the bolts hitting the roof…i had this problem with one of my cars, i was able to just flip the bolt over and had no problem…probably depends on the attachment though
I used to drive an expedition.
I used yakima towers and carried 2 canoes with a combined weight of around 100lbs with NO problems. I felt I could easily carried another 50lbs with no worries.
I doubt your 3 kayaks will weigh as much as my Supernova and my 17’ 1968 Pat Moore boat(heavy glass).
150 pounds
Looks like he’s carrying 150 pounds of kayak. Might be a tall order for most factory racks.
‘98 Expedition
I have a ‘98 Exp. I got some 6’ - 8’ green strut bars from lowe’s and secured them to the factory rack. I have hauled a Wenonah Spirt 2, Wenonah Encounter, and a Wilderness System Tsunami on that rack at the same time. No problems on any trips I have taken. Crazy looking, but works.