People who are helping diagnose certain brake problem conditions - in particular a hard brake pedal - often suggest that you measure the vacuum pressure. The advice will sometimes mention that your engine must produce more than 18” of vacuum to give that nice easy pedal feel. In fact, we just provided that explanation in our recent Tech Talk article on diagnosing causes of a hard brake pedal.
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.
Make no mistake about it, most classic car enthusiasts like to go fast. We spend countless hours in the garage figuring out ways to go faster. Adding more horsepower guarantees you’ll impress your buddies and have a blast every time you pull away from a red light, but that extra giddy-up can cause some problems too.
Topics: Tips and Info, Disc Brake Conversion Kit, Master Power Brakes, Hard Brake Pedal, disc brake technology, tech tip, rear disc brake conversion, front disc brake conversion, Better Classic Car Braking
Converting from manual to power-assisted brakes is a major upgrade and one of the most common projects that we discuss with customers. Due to the different size requirements for brake boosters and master cylinders, you may need some help sorting out the available options to optimize your vehicle’s brake system performance. That’s where the tech pros here at Master Power Brakes really shine.
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.