2005 fx f150 brake pedal works fine on first stop but after that it goes to the floor if you pump it it goes normal and it repeats this process?????? fluid levels are full no sign of brake cylinders leaking?????can you help

start the bleeding process by opening the longest line first. Get a mate to help with the process . Pump the pedal a few times and hold it down while the bleed screw is opened. tighten the screw and pump up again open bleed screw . Repeat process until no air comes out of the screw . Repeat the process back to the last line. Keep the master cylinder reservoir full during the processes.. Operational brakes will work wit or with out the booster . The booster only reduces the amount of energy you have to exert to put the brakes on

bad master cylinder.. normal for pedal to get hard while pumping pedal with engine off.

Try this,apply the emergency before stepping on the brake.
If this helps the pedal,the rear brakes are out of adjustment.

do you mean that you pump the brakes to build up pressure in order to stop?

bleeding brakes requires you to bleed them from each wheel starting at the right rear. procede as follows: have someone sit in the drivers seat. have them pump the brakes slowly and forceably to build up pressure. maintain force on the pedal. starting at the right rear, open the bleed screw slowly. the pedal will go to the floor and the fluid will drain. hold the pedal to the floor and tighten the bleed screw. repeat this procedure several times until you are sure there is no air in the line. follow these steps at each wheel- left rear, right front, left front. keep reservoir filled with fluid. fill after each wheel. (note) get a length of rubber hose that fits snuggly over the end of the bleed screw
and drain fluid into a container.

i think you were draining the anti-lock brake system. in which, case follow the steps above for that also.

pump the pedal about 10 times and see if it comes back up, u need to pump the caliper pistons out after a brake job.

It may be an internal leak in the master cylinder which will allow the pedal to go to the floor with no loss of fluid. I hope this helps.

sounds like a bad diaphragm in your brake booster. listen for air while running at booster , disconnect vacuum hose depress pedal if it is good there should be a big difference in pedal

Hello

With regards to the brake lights, you need to replace your brake switch located under your brake pedal.

With regards to spongy pedal, sounds like air in the line you need to bleed the brakes via the bleed nipple on each caliper and check your brake fluid.

hope this helps.

Thanks

are your rear drums set up? why did you bleed the brakes. when only when you installed new pads?

My 03 trailblazer does the same thing and the service dept. told me that it was normal for this model to do that, it has never failed to stop but if your sitting at a red light you can feel the peddle go down to almost the floor but it stops fine and it has done this since day 1 and they say thats normal on the trailblazer.