Having same problem. Vehicle had leak on the left front caliper. Replaced both front calipers, and pads. Had no pedal after full system bleed. Removed vacuum line from booster and pedal was good while running. Replaced brake booster. Still having same problem. Have done a manual bleed from each wheel, bled from master, bled from ABS, gravity bled, and attempted an automated bleed. The pedal feels great until we start the car. No evidence of leaks, There is a good pedal and no leaks at the master, so the master isnt leaking from the cup seals. And the system seems to be fully sealed. Not seeing any air when bleeding. Went through 7-10 bottles of brake fluid while bleeding, and just cannot fix this problem. you have to pump the pedal twice to get enough pressure to stop. Vehicle is very unsafe and We simply cannot figure out what could be causing it. The only thing we havent tried is pressure bleeding the system, but we did try everything else we could think of. Any help would be much appreciated.

Your best plan is to go back to basics. Raise the vehicle onto axle stands for safety and strip the caliper back off. Check the pipe is fitted correctly and isn't leaking fluid. Examine the pads to make sure they are the correct ones for that caliper and they are the right way round. Remount the caliper without the pads to check the body slides on the pins smoothly. Using a piston tool make sure the piston slides all the way in.
Remove the caliper and refit it WITH the pads. Refit the wheel. Don't lower the car. Get a helper to pump up and hold the brake pedal. Try to turn the wheel by hand, it shouldn't turn. Release the pedal. The wheel should turn freely. If it doesn't, you might need to bleed the entire system. Do opposite corners, Front right, rear left, front left, rear right. KEEP CHECKING the brake fluid reservoir doesn't run dry.

The first thing is to make sure the caliper piston is all the way in, the caliper then slides over the brake pads and bolts on, make sure you have the correct caliper on the right side, the way to know this is when caliper is on the little bleeder screw should be on the top, if it is on the bottom then wrong caliper, try the other one,

After caliper is on you will then need to bleed the brake system,
This all depends on what happened, if the brake fluid did not all leak out and caliper was just bad then before removing brake hose off old caliper pinch rubber brake line with a pair of needle nose grips or there is a line crip tool that crips hose to avoid fluid from leaking out. this makes bleeding easier , other wise you will need to make sure fluid is full and start at the right rear wheel bleeding and move to left rear then right frt and last left front, you will need to keep an eye on the level of brake fluid and add as need to keep it from going empty,
you will need some one to pump and hold brake while you bleed them, pump pedal three times and hold down while you open bleeder screw, this is to be done to every wheel about four to five time to make sure all air is out . good day. note if pedal feels low bleed again wont hurt anything just a little more fluid lost.

Sound like you either have air in the system or a leak. Make sure all the connections are tight on the new calipers. clean off all the connections and blessed screws with brake cleaner. Then have your partner press on the brake pedal while you look for leaks. Reblead the entire system again starting at the right rear, than the left rear, than the right front, and finally the left front. Continue bleeding at each wheel until no air comes out. make sure you don,t let the master cylinder go dry. It will take several pedal pumps for the caliper pistons to take up the gap in between the pads and rotors. I assume you have a helper pushing on the brake pedal during the bedding process?

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This may sound dum but its been done a few times and is a simple mistake , the bleeder screw is up top, with the caliper on the bleeder screw should be up top, if not then calipers are on the wrong side, it sounds like air in the system, also you pumped the pedal up to push out the piston so pads hit rotor after bleeding,i dont see anything else, if the pedal is good with pinched lines at caliper then it got to be calipers are wrong or on the wrong side and the bleeder is not atop caliper,also you bleed the rear also? these trucks and cars use left caliper and rt rear on one system of the master and rt front and left rear on one side, let me know about the caliper, heres a picture to show you what i mean. hope this helps

BY TRUCK HAVING ABS BRAKE.YOU NEED A SCANNER TO BLEED BRAKES THE SCANNER HAS TO RESET OPERATION OF THE BRAKE HYDRALIC SYTEM BEFORE YOU CAN BLEED SYSTEM.

Its not air leak, you must bleed air from system. You have to bench bleed the master cylinder, then bleed each caliper starting from the right rear, then left rear, then front right, then front left. If you've already done this, then do it again, you must have air in your lines or they would work. The only other thing could be your rubber lines are bad and swelling(absorbing the hydraulic pressure) but they would have to both be completely mush.

For front brake pads replacement you need only usually wrench set, inclusive 7 mm allen key also. But for rear brake pads replacement you need obligatory a special caliper piston pressing tool, in order to press back rear caliper piston with parking brake automatic adjustment!!! For front brake pads. First you must verify yours front brake disc diameter: 280 mm or 288 mm. (On my car y have 288 mm). After that you can buy the brake pads (with wear sensor). For change front brake pads you must raise vehicle, remove wheels, extract the retaining spring of the caliper, and remove the caliper as follow: 1. Do not disconnect the brake hose from the caliper, and do not allow the caliper to hang by the brake hose! 2. Remove top and bottom caps (on back side of the caliper) for access to guide pins, then unbolt and remove them from the brake carrier. Remove the caliper. 3. Now you must thoroughly clean the brake calipers (free of grease). 4. Remove outer brake pad from brake carrier. 5. Pull inner brake pad out of brake caliper piston. 6. Check up the brake fluid level on the reservor, and emptying if neccessary! 7. Push piston back into brake caliper housing. 8. Install inner brake pad (with expanding spring) in brake caliper piston. (Arrow marked on pad - if exist, must point in direction of brake disc rotation when vehicle is moving forward). 9. Install outer brake pad into brake carrier. 10. Bolt brake caliper housing to brake carrier using two guide pins. Tightening torque is 25 Nm. 11. Install both caps. 12. Insert retaining spring into brake caliper housing. Important: Depress the brake pedal firmly several times while the car is stationary so that the brake pads adjust to their normal operating positions!!! Check brake fluid level and top up if neccessary!!!

There is either air in the system or the brake hoses on one or both of the front calipers is worn and spongy.Solution:1st bleed the system(front) with a Mighty Vac hand pump.Maintain full fluid level.2nd check front calipers and hoses for leaks and cracks.Replace if needed

You may have a leak in the booster or master cylinder. You can put a pressure tester on the system to test for leaks. It does sound like you have an air leak.
You can try to bleed the master cylinder, then slave cylinder, then brake lines.

Sounds like you still have air in your brake lines. Make sure all your brake lines are tight. Then bleed again. Bleed the trouble side first, meaning right side, then go to front left, back left then back right, make sure that your brake fluid is also full