I've had problems with my front brakes dragging and making some noise and eventually clamping down so my truck wouldn't drive. Then they went out and I had to push the pedal to the floor to stop.

My first thought is that the master cylinder is out, but none of the descriptions I can find involve the brakes sticking or dragging like I have had. But both sides seem to brake equally so I doubt it is just one caliper or the other and its unlikely both failed simultaneously. Before I start replacing parts does anyone have some advice about how I can narrow down the problem? Thanks for the help.

The truck is a 2WD Automatic 2004 Ranger.

Dragging front brakes are usually caused by seized calipers or rusty slide pins. Or both. Take them apart for cleaning, or replacement. Are the slides effortless? If not, wire brush 'em, and apply grease. Make sure the caliper operates freely on the slides. Also that your caliper piston is not jamming against a (rusty or scoured) piston cavity (you can buy caliper rebuild kits). I presume no dirt inside the lines? Did you bleed them wide open to remove any possible internal rust chunks that could plug the brake line?

Other than the calipers & slides, perhaps another possibility is that the Master Cylinder is not retracting when you release your foot from the brake pedal. Maybe the MC internal return-spring(s) are shot? In that case, test it with a simple pressure gauge attached to the MC port supplying the front brakes. The pressure should subside when releasing the brake pedal.

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1997 4x4 Mazda B4000 SE, Ext.Cab

Could also be the hoses going to the calipers are bad.

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1999 Ranger 4.0 and extreme Snap-on tool fetish

This↑ way to check them is open the bleeder and and see if they back off.

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97 ranger reg cab 2.3 5 speed. 2 wd no ac. Mods after market jvc head unit & throttle cable. 06 mirror upgrade.