The Ford Barn - View Single Post - new model A owner, modification questions

Kevin in NJ · 12-10-2013, 02:32 PM

Steve let me explain.

The problem with juice brakes are they do not like to sit. It is worse with the older style systems and dependent on climate. The reason it is worse on the older cars is the lack of any check valve. The check valve holds a bit a pressure on the system keeping the fluid going in one direction.

Once the pressure is equalized, then you can get a daily pressure change. As the temps vary through the day you get the liquid pressurizing and then a slight vacuum. This allows the brake fluid to meet water at the wheel cylinders. Of course you also get condensation on the metal in some areas. This allows for the wheel cylinders to get royally mucked up. That wheel stops having a braking action. Now we have a safety issue.

I live in southern NJ near the shore. I can 40+ degree differences at some times of the years along with condensing moisture. We had a 39 Ford that we just did not drive enough and every 2 years we were pulling a rear drum off to clear up a wheel cylinder.

Here is the real kicker. A good number of people do not bother keeping their cars in good working order. The brakes kind of stop the car so they do not bother doing anything about it. I started asking questions at a car show one year (Smithville for those that are local). This was after I had the rear wheels muck up on my 65 Mustang. Half the cars there had some issue that indicated lack of braking. Several guys KNEW their cars did not have rear brakes and never bothered to fix it.

So are brakes that can just fail from sitting safer then brakes that just keep working?

The added detail that is sometimes lost with Model A brakes is the fact that properly done mechanical brakes have the same stopping power as juice with the original type tires.

I had a discussion with one of the Miller's (they own Carlisle and lived near me) about this problem. He said he never had a problem with his collection of Vettes. Of course, he has a climate controlled garage. I would also believe that there are some areas of the country where the brakes are much less likely to have problems. Like the guys that live in the perfect weather of CA.

Hope that makes sense.

12-10-2013, 02:32 PM	#24
Kevin in NJ Senior Member Join Date: May 2010 Location: South East NJ Posts: 3,398	Re: new model A owner, modification questions Steve let me explain. The problem with juice brakes are they do not like to sit. It is worse with the older style systems and dependent on climate. The reason it is worse on the older cars is the lack of any check valve. The check valve holds a bit a pressure on the system keeping the fluid going in one direction. Once the pressure is equalized, then you can get a daily pressure change. As the temps vary through the day you get the liquid pressurizing and then a slight vacuum. This allows the brake fluid to meet water at the wheel cylinders. Of course you also get condensation on the metal in some areas. This allows for the wheel cylinders to get royally mucked up. That wheel stops having a braking action. Now we have a safety issue. I live in southern NJ near the shore. I can 40+ degree differences at some times of the years along with condensing moisture. We had a 39 Ford that we just did not drive enough and every 2 years we were pulling a rear drum off to clear up a wheel cylinder. Here is the real kicker. A good number of people do not bother keeping their cars in good working order. The brakes kind of stop the car so they do not bother doing anything about it. I started asking questions at a car show one year (Smithville for those that are local). This was after I had the rear wheels muck up on my 65 Mustang. Half the cars there had some issue that indicated lack of braking. Several guys KNEW their cars did not have rear brakes and never bothered to fix it. So are brakes that can just fail from sitting safer then brakes that just keep working? The added detail that is sometimes lost with Model A brakes is the fact that properly done mechanical brakes have the same stopping power as juice with the original type tires. I had a discussion with one of the Miller's (they own Carlisle and lived near me) about this problem. He said he never had a problem with his collection of Vettes. Of course, he has a climate controlled garage. I would also believe that there are some areas of the country where the brakes are much less likely to have problems. Like the guys that live in the perfect weather of CA. Hope that makes sense.