The most common question that is asked of our Technical Representatives is why do I have a hard brake pedal. Right behind that in frequency is the direct opposite question of why do I have a soft brake pedal and what might be causing it. This question is usually a little easier to answer but the answers can often be forgotten and might need a little reminder.
Here’s a scary scenario we all dread as drivers. You’re cruising down the highway, wind flowing through your hair and “Born to be Wild” pumping from the stereo. Up ahead traffic begins to slow and you gently tap the brakes. To your horror, nothing happens! The pedal is stiff as a plank of wood. You have to practically stand on the brake to slow the vehicle down, but it does so eventually. Phew!
This post on vacuum pressure is the first of our 4-part series in which we take a deep dive into diagnosing the most frequent causes and solutions related to a hard brake pedal.
Whether your vehicle has power or manual brakes, pedal ratio is important. If you are experiencing a hard pedal you should check your pedal ratio if you have converted from the vehicle’s OE set up. As a general rule, your pedal ratio should not exceed 6:1 for manual brakes with a 1” bore master cylinder and 4:1 for power brakes with a 1-1/8” bore master.
Pedal Ratio is one of the most overlooked parts of a brake system. One of the main reasons and causes of a hard brake pedal is simply due to incorrect pedal ratio. When a brake pedal gets modified to “fit” in a vehicle or a booster/master cylinder gets installed where it “fits” in the car, the pedal ratio is rarely taken into consideration. Proper pedal ratio is a must when installing and operating a brake system.