You had questions; we had answers. And then you had more questions!

A while back, we had the Summit Racing guys answer some of your common brake master cylinder questions. In this video, they take on a few more of your questions, including:

  • Can you use a drum brake master cylinder on a disc brake system?
  • What is the proper piston bore size on a manual brake master cylinder?
  • Can you use a manual brake master cylinder to operate power brakes?

Watch now to get the answers!

 

Today, we are going to answer your questions about disc brake master cylinders, drum brake master cylinders as well as the differences between master cylinders for power brakes versus manual brakes. So let’s start with disc brake master cylinders versus drum brake master cylinders. Typically a disc brake system is going to require more fluid to operate properly, so a disc brake master cylinder will simply hold more fluid than a drum brake master cylinder. On a drum brake master cylinder, you will also have residual pressure valve to maintain a certain amount of pressure at all times. This is to prevent air from entering the braking system.

So can you use a drum brake master cylinder on a disc brake system? We hear that question quite often. You can, but you are going to compromise some of your braking effectiveness, and the reason is simply because once again the drum brake master cylinder holds less fluid than the disc brake master cylinder. And again, that disc brake system requires that extra fluid to operate at maximum effectiveness. Also, that residual pressure valve that we told you about on the drum brake master cylinder is going to cause a little bit of a drag on the disc brake system’s rotor and that is going to affect the overall braking ability of the system.

Another question we hear is can I use a disc or drum brake master cylinder on a four wheel disc brake system and the answer is simply, no you cannot. You are going to need to use a special master cylinder design just for the four wheel disc brake system to get the proper amount of brake fluid volume and pressure to operate the four wheel disc brake system properly.

Now we are going to talk about manual brake master cylinders and power brake master cylinders. On a manual brake master cylinder there is going to be a smaller piston bore to maintain the proper fluid pressure required to operate manual brakes. There is also a deeper hole for the brake pedal push rod. Now you can use a manual brake master cylinder to operate power brakes but not vice versa. Power brake master cylinders have a larger piston bore diameter and are not able to supply the fluid pressure required to operate a manual brake system.

Another question we get regarding manual brake master cylinders is what is the proper piston bore size or piston bore diameter. You are not going to want to go any larger than a one-inch diameter in order to maintain the proper fluid pressure to operate the manual brake system. If you have more questions regarding brake systems or any high performance related topic feel free to leave a question in the comment section below.

Author: David Fuller

David Fuller is OnAllCylinders' managing editor. During his 20-year career in the auto industry, he has covered a variety of races, shows, and industry events and has authored articles for multiple magazines. He has also partnered with mainstream and trade publications on a wide range of editorial projects. In 2012, he helped establish OnAllCylinders, where he enjoys covering all facets of hot rodding and racing.