Do I Have Power Brakes or Not?

I recently overheard an exchange taking place at a car show about whether or not you could make drum brakes into power brakes.

“Aren’t drum brakes always manual and disc brakes always power?” one fellow asked.

“That’s right. It’s why they have disc brake conversion systems,” a second fellow chimed in.

“Whoa, not so fast!” I said, stopping to jump into their discussion.


On one side, you have brakes that have no power assistance to the pedal, which we call manual brakes. On the other side, there are brakes with power assist, which make the pedal easier to depress, otherwise known as power brakes. A classic or hot rod car can have manual disc brakes or power-assisted drums.

“I thought a power booster was required equipment with disc brakes,” said one of my new buddies.

“No, is the short answer. Even though a power booster gives you a good pedal feel, manual disc brakes work fine,” I explained.

The real difference between power and manual brakes is whether or not the master cylinder has a power brake booster attached. Simply put, a power booster helps assist the master cylinder piston to apply force when you press the brake pedal.

All the brake hardware at the wheels will be the same, power or manual.

The booster is typically using vacuum pressure from the engine or a vacuum pump to help you apply pressure to the brake pedal. The reason people like a power booster is that you use less foot pressure on the pedal to get firm braking action. Originally presented as a new car feature “for the ladies,” the addition of a power booster meant you didn’t have to use every last ounce of leg power on the brake pedal to stop on a dime.

Converting your classic or street rod to employ a power booster along with a new master cylinder (replacing your current manual master cylinder) is a simple bolt-in installation.

Safety First: Dual Master Cylinder

Many cars prior to the 1970s used a single reservoir master cylinder. This is not the safest of situations. If a master cylinder should fail and there is only one line and reservoir, you will effectively lose brakes on the entire vehicle.

With a dual reservoir master cylinder, you have the security knowing that after converting with one of our kits, the front and rear braking systems on your car are completely separate from one another. It doesn’t matter whether or not your car came with a single or dual reservoir master cylinder to begin with, we have safety in mind in our conversion kits and always provide a dual reservoir master.

Upgrading to a dual reservoir master cylinder should be the first upgrade you make if your car is a daily or frequent driver and is currently equipped with a single reservoir master cylinder.

Article Courtesy of: Master Power Brakes

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32 Responses to “Do I Have Power Brakes or Not?”

  1. Wayne A Schirner

    I want to upgrade my 1954 Chevy 3100 pickup to power disc brakes. Some kits I see say they can't be used on vehicles with a manual transmission. I also see that comment with dual chambered master cylinders. What are my options, since I have a manual transmission?

  2. Janedon (my fem name)

    Yup--I've had total brake failure on Older cars probably 1/2 dozen times & things got harry a few times -Including having to drive into a ditch to avoid a truck--One doesn't Need power brakes but that second Reservoir is very important-

  3. Robert Harvey

    I think a better terminology would be twin piston master cylinder, the reservoir in some cases whether twin or not could be irrelevant.

  4. Gray

    Change power bolster on a 65 mustang

  5. Robert Collinson

    I owned a 1970 GTO Judge that came from the factory with the 370 hp 400 and it had drum brakes all around! It's hard to believe GM didn't require disc brakes with their most powerful engine.

  6. Chuck Udell

    I have a 1956 Chevy pickup with a 79 Cameroon front clip with the stock disc brakes that came with it. On then rear I gave an explorer diff with Disc brakes. I believe they are the ones with the smaller bore. I want the mount my master cylinder on the fire wall with hanging pedals ( it’s a 5.3 LQ4 an auto). What do you recommend. I really don’t care if they are power or manual.

  7. Lou

    power Drum brakes have been around since the 40s ! discs didn't even exist on most American cars, 'cept the corvette until the late 60s, and then either power or not, it was an option.

  8. Chris

    Please no offense, but your article, especially this one comes off as very innocently amateur. Can we get past the very basics? I would not buy a subscription for this.

  9. Joe Celosky

    Disc Brake Conversion: I have been unable to find any rear drum brake conversion kits for my 1952 Dodge 1/2 ton pickup. My current thought is to just swap the rear end for something with rotors or which can be readily converted. What are some items to consider (span to leaf springs, span to inside/outside tire, drive shaft angle/length, master cyclinder distribution pressure, etc.).

  10. Ed Beach

    I have a 65 Mustang with Factory Power Drum Brakes. i would like to upgrade to Disc Brakes on the front. i would like to know if i can use the existing Booster, Pedal and rod if i convert to a dual master cylinder. so far i have not found the answer.