My younger co-worker/friend has a 2010 Ford F-150 4x4, auto that has been having front left brake caliper issues. He says that after each time its replaced (3x), its fine for a time, then caliper keeps seizing up, and wont retract, resulting in pads worn out fast, and the rotor is destroyed. So I told him I would help him out with my tools, and guide him, but he would have to do it so he could learn how to wrench on his own ride.
He purchased OEM replacement caliper, rotor, and new pads. Before replacement, I saw no obvious fluid leaks, unusual wear, damage, etc. And front end looked OK, except it could use an alignment (he says it pulls slightly to left at highway speeds), and the tires shown some inside wear (but not excessive). we then proceeded to replace the front left caliper, rotor, and pads on both sides. All components on right side looked OK, but we replaced the pads anyways. We bled the system, and all is good now. Brakes are solid, and no shakes or other symptoms.
However, I told him if this is the third time the caliper has gone out, then something else is wrong. I did notice his fluid was kinda dark and dirty, and when I bled the brakes, some funky stuff white stuff came out into my bleeder jar. Of course it had some air bubbles, but only the front left had a milky stuff come out too. I suspect that dirt or other contaminant is in his front left line, or master cylinder, and that it is causing the caliper to wear out fast, and eventually seized up/fail to contract properly, resulting in quick and excessive pad wear, and rotor damage only on the left side.
Also, when we were bleeding the system (with truck running), I noticed an automatic "pumping" sound would intermittently come on from around the master cylinder area under the hood. He said it was the fan, but I noticed it was coming from the rear of the engine compartment (not the radiator fan shroud) and he did not have his heater fan on at the time.
Long story short, I suspect he he has a bigger problem, and the caliper issue is a symptom of something larger. Maybe his master cylinder is going out. Any knowledge from the "Great and All Knowing Scotty" is much appreciated.
By the way, my 19 year old son and I watch all your videos, and it has helped me as I try to pass on my DIY mechanic knowledge to my boy. He listens to you, more than me! Thanks Scotty! Keep up the great job teaching the masses! It means alot, and saves regular folks hard earned money, and teaches them how to be independent. "Ring That Bell!"