1956 Brake booster woes

[pops52]

My '56 has had a hard pedal for years now and I'm determined to fix the power brakes. With my foot on the pedal when I start the car the pedal doesn't move. With the engine off the pumping the pedal has no effect (as if the vacuum is bleeding off). Today I disconnected the vacuum line to the booster and I have 23 in of vacuum at idle. I feel the check valve is working as I cannot blow on the line but can suck air in. when sucking air in I think I can detect the diaphragm moving but I am not 100% sure of this.

Could anyone help walk me through trouble shooting this so I can have some confidence in the parts I may need to purchase?

Thanks,
Clay

 

[biddle]

Please include model year in your subject on future posts.

 

[CtCarGuy]

My '56 has had a hard pedal for years now and I'm determined to fix the power brakes. With my foot on the pedal when I start the car the pedal doesn't move. With the engine off the pumping the pedal has no effect (as if the vacuum is bleeding off). Today I disconnected the vacuum line to the booster and I have 23 in of vacuum at idle. I feel the check valve is working as I cannot blow on the line but can suck air in. when sucking air in I think I can detect the diaphragm moving but I am not 100% sure of this.

Could anyone help walk me through trouble shooting this so I can have some confidence in the parts I may need to purchase?

Thanks,
Clay

I ad the same problem and found the booster was bad. I sent it out to be rebuilt (not cheap) but now I have decent brakes (power disk front, drum rear) Larry

 

[cokefirst]

Even under ideal conditions the Midland power booster was only marginally effective in reducing the pedal pressure required to stop the car. One problem with the midland unit is that in combines a vacuum booster with a cylinder. Most vacuum power assist brakes are just a vacuum booster paired with a master cylinder. This unit has a wet brake fluid cylinder paired with the booster in addition to the car's master cylinder. Brake fluid has the affinity to attract moisture which is hard on the moving parts of the brake system. This moisture causes the fluid to turn color and the moisture has a corrosive effect on the parts. If your booster has not been rebuilt in the past 30 or so years, it is likely plugged and is simply allowing the fluid under pressure to pass through with no assist. At one time, the overhaul kits were available for these boosters. Midland has stopped supporting this unit and the remaining parts were purchased by a power brake shop in Southern California. You may want to have your unit rebuilt by a qualified rebuilder. It is also a good idea to purge the brake fluid every 2 years or so and replace with fresh fluid to remove the moisture from the system.

 

[JRH]

Even under ideal conditions the Midland power booster was only marginally effective in reducing the pedal pressure required to stop the car. One problem with the midland unit is that in combines a vacuum booster with a cylinder. Most vacuum power assist brakes are just a vacuum booster paired with a master cylinder. This unit has a wet brake fluid cylinder paired with the booster in addition to the car's master cylinder. Brake fluid has the affinity to attract moisture which is hard on the moving parts of the brake system. This moisture causes the fluid to turn color and the moisture has a corrosive effect on the parts. If your booster has not been rebuilt in the past 30 or so years, it is likely plugged and is simply allowing the fluid under pressure to pass through with no assist. At one time, the overhaul kits were available for these boosters. Midland has stopped supporting this unit and the remaining parts were purchased by a power brake shop in Southern California. You may want to have your unit rebuilt by a qualified rebuilder. It is also a good idea to purge the brake fluid every 2 years or so and replace with fresh fluid to remove the moisture from the system.

Is there a quality replacement for the Midland booster?

 

[Ward 57]

Even under ideal conditions the Midland power booster was only marginally effective in reducing the pedal pressure required to stop the car. One problem with the midland unit is that in combines a vacuum booster with a cylinder. Most vacuum power assist brakes are just a vacuum booster paired with a master cylinder. This unit has a wet brake fluid cylinder paired with the booster in addition to the car's master cylinder. Brake fluid has the affinity to attract moisture which is hard on the moving parts of the brake system. This moisture causes the fluid to turn color and the moisture has a corrosive effect on the parts. If your booster has not been rebuilt in the past 30 or so years, it is likely plugged and is simply allowing the fluid under pressure to pass through with no assist. At one time, the overhaul kits were available for these boosters. Midland has stopped supporting this unit and the remaining parts were purchased by a power brake shop in Southern California. You may want to have your unit rebuilt by a qualified rebuilder. It is also a good idea to purge the brake fluid every 2 years or so and replace with fresh fluid to remove the moisture from the system.

You are correct but rebuild kits are available from CASCO and even have rebuilts. I bought the kit and had a local shop do the labor. The insides were just as you describe. They DO make a difference.

 

[cokefirst]

There is not a replacement for the Midland booster. There are several conversions to disc brakes, dual master cylinders, etc. If you do not care about authenticity, you may want to look into these. The business that bought the parts inventory from Midland is Karps Power Brakes in Chino, CA. They will rebuild your unit or sell you the rebuild kit.