Changed caliper on 2005 ford freestar and now brakes are spongie.

Bleed ALL lines at calipers....

abs control module bad allowing internal regurgitation of fluid.

700-1200 bucks depending on your vin which the dealer will need to get the right one for you.

There is air in the brake system and must be bled. They have devices for bleeding the system...basically you need to replace the air with fluid. Hope this helps !

get someone to stamp on the pedal when your opening the bleeder and close it before he/she hits the floor with there foot.may take several attempts.

loosen of the hand-brake adjustment and press the brake pedal a few times to self adjust the rear brakes.
Re-tighten the handbrake adj last.
Front brake sounds like a seized caliper,If possible remove caliper and clean and lubricate the piston.
This may work but replacement caliper may be the only other solution.Make sure the caliper slides are also clean and lubricated and the brake pads are in good order.(TRY THIS FIRST)
Also new brake shoes can make the pedal feel spongy for a couple of hundred miles until they have been run in.

So long as the brake booster is working, test it by turning on the engine, press the brake pedal all the way down, then shut off engine keeping your foot on the brake pedal, if the pedal comes up slightly pushing against your foot then the booster IS working.

Did you BLEED the brakes??????

Did you adjust the rear shoes out? If the rear drum brakes are out of adjustment they will give you a lot of pedal travel. If the pads are worn have no fear of that U-CLIP brake spring, just change one shoe at a time. Take the spring off one side, change the shoe, put the spring back on the post and do the same to the other shoe, no problem.

I just went to Brake Masters this morning and had them replace the Master Cylinder since I was experiencing the pedal very spongy and going to the floor. When they replaced the Master Cylinder and they gave me back the car, the brakes were still spongy and going to the floor. I addressed this to them and they took another look at it, but when I took it for a second time, the brakes were extremely spongy. It was almost like they gave me back my car in worst condition to when I brought it in. Can you help?

possibly new master cylinder is defective

Try checking the caliper on the side that's wearing down faster. Make sure the caliper seal where the cup is does not have any damage. But it might be due to the fact that you only bled 3 out of 4 lines. Good Luck And PEACE