Butyl windshield sealer. Cures flexible. If you leave it in the truck, remove the crumblies and all grease, dirt and oil. Make 8 wood wedges about 4 inches long, one inch wide and 1 inch on the thick end. Add a thin smear of grease to the sides of each wedge. Just enough to say some is on there. Insert wedges by the pair, front and rear, opposing each other. Move them toward each other to attain the proper distance. Place in 4 positions to center the bearing in the housing.
Apply the butyl to the rubber surfaces with a gloved finger, pressing and smearing the butyl on to the rubber with some considerable effort. Now fill that particular cavity with butyl. You may need some tape on each side to keep it in place.
Out of the truck, lay it on something that it won't stick to, and make whatever blocks you need to center everything. Apply as mentioned above.
Do NOT use RTV! Or latex caulk for that matter!
Of course, this is ONLY if you aren't able to find one anywhere.
The last time I bought a center support bearing, it came with the whole cage, bracket and all.
