Troubleshooting a Hard Brake Pedal: Common Culprits and Solutions

What does it mean when the brake is hard? If the brake is hard and you need to exert extra effort when pressing the brake pedal it means that there is a problem with the power brake unit.  

Most cars are equipped with vacuum-assisted power brakes to make the car braking easier. If something is wrong with the power brakes unit it requires the driver a lot more effort to press the brake pedal to stop the car. Vacuum-assisted power brakes use vacuum from the engine to help in applying the brakes, a vacuum hose runs from the engine to a round metal or plastic canister located between the brakes master cylinder and the firewall.

What causes a hard brake pedal?

Some indications which help pinpoint the problem are:

1. If the engine always runs rough, it's likely the problem only involves a broken/leaking vacuum hose.

2. If the engine runs roughly mainly when depressing the brakes pedal while the vehicle is standing still, the power brakes canister has failed.

Causes of the hard brake pedal

1. Broken or leaking vacuum hose

2. Failing power brakes canister

What to do?

First, determine what type of power brake the car has. Open the hood and locate the brakes master cylinder. Refer to the vehicle's manual if you are having trouble finding it. Now, the power brakes unit (whatever type) is located between the brakes master cylinder and the firewall.

A vacuum-assisted unit will be a round plastic or metal canister, about 10" - 14" in diameter and about 4" - 7" deep. Is this what you found?

If yes, check the hose which connects the unit with the engine. Look for cracks or leaks and replace as necessary. If the hose looks, bring the car to a repair shop and ask the mechanic to check the brake system.

For another type of power brakes unit, a "hydro-boost" feeds off the power steering unit. If the engine speed doesn't change when depressing the brakes pedal, the vehicle has a hydro-boost unit.

If the car has a hydro-boost power brake unit (i.e. you did not identify a canister-type device as described above), seek the help of a qualified mechanic. Unfortunately, power brakes units are "throwaway" items and therefore when one goes bad, you probably have no choice but to replace it with a new one as opposed to a rebuilt.