The Ford Barn

jplutz · 04-23-2023, 11:59 AM

Greetings, I have had the following problems since I purchased the car in 2021. The previous owner has sadly passed away. I have installed new front wheel cylinders, shoes and springs, and a new master cyl and bled the front system. I also changed brake light switches 5 times, finally putting in a Harley C switch. Every time I re!ease fluid pressure, the pedal goes down an inch or 2, but after driving a mile or so, the pedal is at the top and hard and the brake light is on. I just put it up on blocks and checked the rear brakes and they look good. It needs rear park brake cables.
I also need new front drums, but only see them at Kanter Auto Parts.
Any help would be appreciated.

JayChicago · 04-23-2023, 05:15 PM

I am no expert, but this sounds like master cylinder push rod out of adjustment. Needs some lash between push rod and M.C. If the master piston cannot totally relax when pedal is released because the push rod is still pushing on the MC, then pressure will be retained in the lines. And with each drive pressure will increase until brakes lock up.

fordv8j · 04-23-2023, 05:38 PM

Jay is right on, adjust rod so has some slack in it....happened on our 38 conv

TJ · 04-23-2023, 07:15 PM

Jay is spot on with the adjustment of the push rod.

Flathead Fever · 04-23-2023, 07:42 PM

Everybody is correct. The master cylinder piston is not returning all the way back to the snap ring. When the piston moves forward the ic closes off a port in the bottom of the reservoir. When the piston returns it uncovers the port and allows the fluid to flow back into the reservoir. If the port is blocked the brakes will stay locked up. Your push rod is too long and not allowing that piston to come all the way back and uncover the return port. You want it short enough that the piston returns to the snap ring at the back of the cylinder with just a little bit of play when you pull back on the pedal.

jplutz · 04-23-2023, 10:30 PM

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My apologies for posting this note twice.
I answered a lot on the other post. This master cyl is from Taiwan. And is "generic" for that era. Do I need a Ford specific cylinder?
Thanks for your help.

Flathead Fever · 04-23-2023, 10:43 PM

First check that rod length for free play. You can also pull the rubber boot off of the back of the master cylinder and see if that piston is coming all the way back to the snap ring. If the rod is not adjustable, I'm sure you can buy one that is. Unless that Taiwan master cylinder has the hole drilled in the wrong spot it should be okay. Its always best to rebuild your original master and wheel cylinders if they are not pitted. too bad, especially if they are Ford script parts you want to try and save them.

04-23-2023, 11:59 AM	#1
jplutz Senior Member Join Date: Sep 2021 Location: Marlboro, NY Posts: 131	1952 Hard Brakes - Brake light stays on Greetings, I have had the following problems since I purchased the car in 2021. The previous owner has sadly passed away. I have installed new front wheel cylinders, shoes and springs, and a new master cyl and bled the front system. I also changed brake light switches 5 times, finally putting in a Harley C switch. Every time I re!ease fluid pressure, the pedal goes down an inch or 2, but after driving a mile or so, the pedal is at the top and hard and the brake light is on. I just put it up on blocks and checked the rear brakes and they look good. It needs rear park brake cables. I also need new front drums, but only see them at Kanter Auto Parts. Any help would be appreciated.

04-23-2023, 05:15 PM	#2
JayChicago Senior Member Join Date: Jan 2019 Location: Chicago Posts: 927	Re: 1952 Hard Brakes - Brake light stays on I am no expert, but this sounds like master cylinder push rod out of adjustment. Needs some lash between push rod and M.C. If the master piston cannot totally relax when pedal is released because the push rod is still pushing on the MC, then pressure will be retained in the lines. And with each drive pressure will increase until brakes lock up.

04-23-2023, 05:38 PM	#3
fordv8j Senior Member Join Date: Jan 2015 Posts: 392	Re: 1952 Hard Brakes - Brake light stays on Jay is right on, adjust rod so has some slack in it....happened on our 38 conv

04-23-2023, 07:15 PM	#4
TJ Senior Member Join Date: May 2010 Location: Napa,California Posts: 6,566	Re: 1952 Hard Brakes - Brake light stays on Jay is spot on with the adjustment of the push rod.

04-23-2023, 07:42 PM	#5
Flathead Fever Senior Member Join Date: May 2010 Location: Yucaipa, CA Posts: 1,360	Re: 1952 Hard Brakes - Brake light stays on Everybody is correct. The master cylinder piston is not returning all the way back to the snap ring. When the piston moves forward the ic closes off a port in the bottom of the reservoir. When the piston returns it uncovers the port and allows the fluid to flow back into the reservoir. If the port is blocked the brakes will stay locked up. Your push rod is too long and not allowing that piston to come all the way back and uncover the return port. You want it short enough that the piston returns to the snap ring at the back of the cylinder with just a little bit of play when you pull back on the pedal.

04-23-2023, 10:30 PM	#6
jplutz Senior Member Join Date: Sep 2021 Location: Marlboro, NY Posts: 131	Re: 1952 Hard Brakes - Brake light stays on Sponsored Links (Register now to hide all advertisements) My apologies for posting this note twice. I answered a lot on the other post. This master cyl is from Taiwan. And is "generic" for that era. Do I need a Ford specific cylinder? Thanks for your help.

04-23-2023, 10:43 PM	#7
Flathead Fever Senior Member Join Date: May 2010 Location: Yucaipa, CA Posts: 1,360	Re: 1952 Hard Brakes - Brake light stays on First check that rod length for free play. You can also pull the rubber boot off of the back of the master cylinder and see if that piston is coming all the way back to the snap ring. If the rod is not adjustable, I'm sure you can buy one that is. Unless that Taiwan master cylinder has the hole drilled in the wrong spot it should be okay. Its always best to rebuild your original master and wheel cylinders if they are not pitted. too bad, especially if they are Ford script parts you want to try and save them.