Soft brake peddle soft unless pumped a couple of

keep bleeding

Brake peddle should be hard, if bake peddle soft check master cylinder or replce, try bleeding brake system too. Ceck if check valve is bad this is located on vacumm line from intake manafold to booter pump body. brake seal at check valve booster pump should hiss if not check vaccumm line for leaks if no leak in line replace check valve they don't cost much.

This sounds like a definite case of worn brake pads. They might have previously fitted pads with soft linings for better stopping power and if your truck is automatic the pads wear down faster on automatics than manual.Ask them to fit pads with harder linings if they have available, but you will have to machine those brake disc's to re-smoothen them or fir new ones(A better proposition) as they are most probably scoured from metal against metal and fitting new pads onto scoured disc's will not only make your brake drums run very hot, but also wear down pads faster than normal and cause poorer braking response.Or maybe that was the problem from the beginning, scoured disks from before a year ago! Check it out good luck.

When you installed new calipers, did you bleed the lines out? Air trapped in the system can cause sticking. Unless they were sticking before you replaced all the parts. Try unplugging the ABS controller under the hood. If that does not work and there is no air in the lines then it would be 1 of 2 things.

1. Master cylinder failing to return.
2. Brake booster not providing enough vacuum.

Start the car. let it run for 10 seconds. while its running pump the brakes. let the brakes go and shut off the car. now press the peddle til it gets stiff. Now hold it down firmly. If the peddle pressure fades, replace the booster.

remove brake fluid filler cap start at the wheel closest to cervo then move away so front to back remove road wheel there is a brake nipple on the caliper put a piece of tubing around nipple and into a jar with clean brake fluid in it loosen nipple get some one to pump brake peddle about 10 times on the final stroke keep peddle pushed to floor then tighten nipple up pump brake peddle a few time should be hard then repeat all wheels rear should only have 1 nipple for rear wheels but check this any way

Unless you have a leak in the brake system the only reason your brake fluid level master cylinder would be empty is that your brake pads are worn out. As they wear the fluid level goes down. You need to check for a leak at all 4 wheels and the complete system. If you find no leak then inspect all brake pads and replace as necessary. I would also bleed the brakes as you let the fluid get very low. More than likely a new set of brake pads will solve your problem. The only thing that is suspicious is the clunk you heard. Make sure a trusted mechanic gives your brake system a good inspection. It can be very dangerous if your brakes fail.

You still have air in the system and must continue to bleed the system to get rid of it.Also you may need to pump the brake peddle for a couple of minutes to bring the brake pressure up again when the job is done.Do not continuously pump the brake peddle.Have a friend depress the brake peddle slowly as you loosen off the bleeder screw,have them push it to the floor and hold it ,tighten the bleeder screw.Foot off the peddle and repeat. Keep an eye on the fluid level in the master brake cylinder and add as needed. This can be a frustrating job and can take a lot longer than you might think.
Just relax, take your time,don't panic.Good luck

Sounds like you will have to bleed your brakes again, but thats not the problem og hard brake peddle, need to check your power brake booster, sit right in back of master cylinder, check make sure it has vacum going to it, also to test it with engine off, press on brake peddle three time, then state engine with foot on peddle, peddle should go down a few inches, also with engine of peddle should feel soft for three pumps, if you have none of this , power brake booster is bad.

that is one of the wosrt ABS system it dose cause a soft peddle but you can sometimes adjust up the rear brakes to help this problem,also find a dirt road and slam on the brakes just enough to cause the ABS pump to kick on it will also give you a better peddle

Don't drive it -- have it transported to a shop for repair -- it's dangerous!