Well I'm not sure but kinda am sure it's not only because I have 2 of these trucks 1997 f150 flareside and 2000 f150 flareside both identical for the most part took that caliper off the 2000 which I know 100% works great (had that truck 5 year so far never an issue) and switched that caliper over and same thing damn break still sticks and gets hot then locks up till I leave it sit a few mintues and I can hear the caliper popping back and releasing some said break booster and pushrod ??? Or pushrod adjustment

 

I don't think so I have 2 of these trucks 1997 and 2000 f150 flareside 5.4l 4x4 both identical for most part I took off the caliper form the 2000 which I know works 1000% have had that truck for 5 years never skips a beat and put it on and same damn thing brake is fine at first then sticks then locks up someone said break booster/pushrod or pushrod adjustment I bout this 1997 from not the brightest individual lol

 

Also was told vacuum leak at break booster or manifold because I do recall while sitting at stop lights hold the break pedal and the truck idles a little funky I DON'T KNOW I JUST KNOW IM GOING NUTS TRYING TO FIGURE IT OUT lol I appreciate any and all help ideas thought philosophy anything that might lead to a cure

 

If only one wheel is locking up, you would think it would be something that only affects that wheel which would rule out the booster.

 

I replaced the master cylinder last night and then both locked up in the front real bad I'm thinking the previous owner screwed with pushrod and it's pre loading my master I'm not sure what's going on but I only have a few parts left to change before the whole damn brake system is new lol and truck does idle weird when at a stop light with brakes applied someone said vacuum leak at booster

 

Only reason I say the is because truck idles perfect till ....I touch the break pedal then idels weird have to look into this even deeper apparently