2009 fx4 5.4l.
my passenger front caliper was stuck and the pistons were cracked and just ****. So I replaced the caliper yesterday, drove around the block, all good.
today drove into town about 20min and now both driver side seem stuck. Both rims were very hot. Some sort of valve or sensor screwed? Feels unlikely the calipers would go at the exact same time.
thanks

 

Yes, it could be coincidental that they all went bad at the same time, but maybe not. Did you do any inspections on the other wheels? If not, I would take the time to remove/inspect/clean and go from there. Be sure to clean and grease the slide pins as well. After all, whatever caused the front pass to fail (assuming age/wear/heat, etc) may also be present in the other wheels.

then, once it is all back together, perform a good oil flush. Start at the rear pass, then rear driver, then front pass and lastly front driver.