Drivers who are experiencing a stiff brake pedal have good reason to look over the entire brake system carefully. We created this 4-part series to help pin-down and even potentially eliminate some issues that could make your brake pedal feel like you are standing on a brick.
If your hard brake cause can’t be identified in the most obvious places we previously wrote about:
- Part 1 - vacuum pressure in the booster
- Part 2 - valving - especially pressure differential valve
- Part 3 - your pedal ratio
...then something else within your brake system must be the cause.
If it's not related to the “top 3 reasons” behind a hard brake pedal, there are several additional possible problem spots for you to examine and troubleshoot. A thorough inspection of the whole system should help you identify any such underlying issue.
In a rear drum brake car, a possible area of concern can be your wheel cylinders. As we mentioned before in the article on valving, the wheel cylinders can similarly create a pressure differential problem. If a wheel cylinder is not moving or is frozen, the hydraulic brake fluid reaches that same wall. When that occurs, the pedal won’t move any further because it is not able to compress fluid. This can be a simple repair if that is the case.
It is also important to look at how much brake fluid is in the system and make sure it is not overfilled. If the fluid can’t return completely to the master cylinder, you could have a scenario where the system is hydraulically locked.
As with most complex systems, there any number of things that can go wrong in the brake system of a power booster equipped vehicle. Start by analyzing the most likely scenarios and problem spots first. More often than not, a hard-to-push brake pedal is directly associated with the power booster, master cylinder or pivot point ratio of your brake pedal.
Through a process of elimination you can likely spot the cause of the hard brake pedal, and then take steps to fix it. If you are unsure of the correct action to take, engage a professional mechanic. Hopefully, the tips above and in the rest of this series will help get your vehicle back on the road soon!