With hard or excessive pedal pressure problems, customer concerns will most likely centre around excessive stopping distances and lack of response from the brakes. As with all customer concerns a road test is necessary to first establish that the problem exists.
http://www.winbrake.com/index.php/downloads/in-depth-training-guides/hard-pedal-diagnosis
If you step on the brake pedal and it has little to no pressure and goes all the way to the floor, especially if you're getting no braking: 1  Low Brake Fluid Level: Check your brake fluid. 2  Air in the Brake Fluid: Even though your brakes operate in a closed system, contaminants can still work there way into the works.
https://www.thoughtco.com/whats-wrong-with-my-brakes-281982
A Training Manual Provided by Wingate Motors. Wingate Motors would like to welcome you to this paper on hard or excessive pedal pressure diagnosis. We shall examine the most common causes and rectification procedures associated with this area of customer concern. Throughout the course of the text, reference to the flow chart below will be made.
http://www.winbrake.com/index.php/downloads/in-depth-training-guides/hard-pedal-diagnosis
When brake fluid boils, it expands and can cause the hard brake pedal that you feel. A brake pedal that is hard to press can also be caused by a build-up of water in the brake line. The water in the brake line lowers the boiling point of the brake fluid.
http://www.diybuildingandrepairs.com/auto-repairs/hard-brake-pedal.html
Worn Brake Pads: Your brakes should never wear low enough to cause your brake pedal to feel low, they'll scream at you before then. But if they do get very low, you might have this problem. Replace your brake pads as soon as possible. Of course, this can be avoided with regular brake inspection.
https://www.thoughtco.com/whats-wrong-with-my-brakes-281982
Brake Pedal Goes To Floor. If you step on the brake pedal and it has little to no pressure and goes all the way to the floor, especially if you're getting no braking: Low Brake Fluid Level: Check your brake fluid. If it's low, top it off to the mark on the side of the reservoir.
https://www.thoughtco.com/whats-wrong-with-my-brakes-281982
Quick Answer. A brake pedal can be hard to push because of several factors, including a brake pedal getting caught on something, failure of the power brake booster or a sticking shoe, which causes the brake fluid to boil. Additionally, a brake can be hard to push if water builds up in the brake line or as a result of a restriction in the brake line.
https://www.reference.com/vehicles/brake-pedal-hard-push-f03caeb35206703
A hard brake pedal can also be the result of a restriction in the brake line, such as a bent brake line or foreign material in the brake fluid. The most common cause of a hard brake pedal is the sticking brake pad or shoe, causing the brake fluid to boil. Tracking down what is causing the hard brake pedal can be frustrating, to say the least. Take the vehicle for a drive and when you come back, feel your brake lines near the wheels.
http://www.diybuildingandrepairs.com/auto-repairs/hard-brake-pedal.html
The most common cause of pedal problems is failure to bench bleed a new master cylinder. Screw the supplied fittings into the outlets and place the tips of the tubes in the fluid in the reservoir. Clamp one of the master's mounting ears in a vise--don't grip around the cylinder--so the unit is as level as possible.
http://www.popularmechanics.com/cars/how-to/a92/1272501/
There are only two plausible reasons for a low pedal: air in the system; and excessive movement between linings and rotors or drums (due to lack of adjustment, an out-of-round drum, or a wobbly disc that's knocking the pistons back so that there's extra space to take up before braking action begins). Isolation.
http://www.popularmechanics.com/cars/how-to/a92/1272501/
what causes brake pedal to be stiff
A brake pedal getting caught on something, failure of the power brake booster or a sticking shoe causes a brake pedal to stiff.