Converting to hydraulic breaks.

S

sr325

Junior Member
Hello, I just purchased a 1930 Coupe that came with a set of hydraulic break backing plates, drums, hubs etc. Turns out one pair (of sets) is the early (39-42) type and the other pair is the later (46-48) type. I purchased Les Andrews book Model A Ford Mechanics Handbook Vol. II in which he provides detailed instructions for how to do the conversion and he states that you should Not mix types. Does anybody have any knowledge/information/experience around this issue and why one should not mix types? Is it an issue of danger? I'm thinking I'll use a two chamber master cylinder so that the front and rear breaks are actuated separately (just for the extra safety aspect). So, it would seem to me that running one type in front (probably the later type) and the other in back should not be a problem.
Thanks so much.
 
If you just got the car don't rush to make modifications until you get to know the car throughly. Many find the original brakes to be as good as hydraulic with none of the work needed.
 
46-48 are a step up from the early brakes. You have one adjustment with the cams to set the shoes. The lower cams (46-48) float so the shoe self centers.
If you use 39-42 hubs new drums are available thru “Krylon” here on the barn. A nice advantage is to be able to remove the wheel, and the drum slides off of the hub to service the brakes.
 
Seems to me that unless you really know your way around brakes, you're asking for trouble to do any conversions. Not a good way to learn.
 
I would suggest putting your general location in your profile. You might want to design your master cylinder mount and linkage and post it for comments.

Also remember you need adapters if you run wire wheels on the later hydraulic brake drums. They look like the fit but don't. https://www.fordbarn.com/forum/showthread.php?p=1286293&posted=1#post1286293

You might find this interesting reading:https://www.jalopyjournal.com/forum...ting-39-48-hydraulic-brakes-to-your-a.124112/ A lot of people plug and redrill the holes in the backing plates but I just elongate mine.

Charge Stephens
 
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When I got my 31 Coupe everything was completely worn out on the original mechanical brakes. It was going to be costly to replace everything. I purchased a used chassis that had 39 juice brakes. I didn't like the way the master cylinder was cobbled on so I made my own battery box with the master cylinder mount. I copied it from looking at pictures of the ones available. I bought new wheel cylinders for it & new brake shoes. I went with a mastercylinder for a 59 Jeep. My brakes work really good.
 
Hi Guys,

Thanks for all the helpful replies. I'm getting that doing the conversion can get complicated and that I need to take things slowly. I've also read that cast iron hubs make a big improvement over the old steel drums. Perhaps that would be a better way to go. My existing drums are definitely in bad shape, heavily pitted and out of round. So, I think they need to be replaced regardless. I'm not trying to build a race car. Just need it to be as safe. Right now it is flat out dangerous to drive. Of course the fact that the steering has about 3.5 inches of slop doesn't help. So, I'm pretty sure I need to get that out and rebuild it too. Breaks and steering are my two top priorities that I'd like to get solved sooner than later so that I can drive it comfortably. Then, down the road I'll need to dig into the transmission as it tends to drop out of 3rd gear from time to time.
 
What is not usually understood by people doing brakes is the fit you need to have.

If the drums and the shoes are not properly matched you will have less then 100% contact and less then 100% braking. To do this properly it takes special tooling. Keep in mind this is just as important doing modern drums like the 65 Mustang I did where nothing fit. I have the special tools so I could make this happen.

With the A the only difference between juice and mech brakes is how fast you can lock the wheels and how the brakes might fail on you. This is assuming stock tires as the weak part is the contact patch of the rubber to the road.

Properly redone brakes will stop the A with confidence. Does not matter which type.

The catch is most people do not have the resources or knowledge to properly redo the brakes.

I have found that mechanical brakes are your better choice based on my experience with the 1939 Ford Forder and the 65 Mustang I have owned and still own the Mustang. Juice brakes in areas with high humidity and not used often will have wheel cylinder fail regularly. I have talked to many car owners of all makes and all years and having rear brake wheel cylinders fail is very common. In my area if you ask the right questions you might find over 50% of the cars have one or more rear wheels with none working rear wheel cylinders. Most just operate that way.

Mechanical A brakes rebuilt with all new parts and properly centered by someone with the correct tools will just always work. There are a number of people who specialize in making up drum backing plate set ups ready to go. This will just work for decades with minimal maintenece and you will always have good solid brakes.

In the end doing any type of brakes on the A is NOT cheap, easy or fast to do them correct.

I should add, a properly restored A to factory tolerences will run 60 MPH confortably all day long. It will stop with confidence and should get over 20 MPG. At least this has always been my families experience with the A's we have owned over the years. Keep in mind these are fairly stock car with little if any changes from factory. Like only Model B cams.

Also you must understand the A mechanical parts were often built to sub- thousandth accuracy. They need to be restored to a similar accuracy. It is actually not much different then building a race car to rebuild the A properly. Once done properly you can run them hard all the time and they just keep going.
 
If you are going to completely rework the steering it might be a good time to consider a newer truck steering. Contact Randy Gross, (714) 292-8660 / (323) 728-5712.

He also sells mechanical brake parts such as new cast iron drums, a good person to know.

Have you at least considered Lincoln brakes?

Charlie Stephens
 
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If it is working fine, don't mess with it. You can make the mechanical brakes function ALMOST as well as the hydraulic.
 
Hello, The Boling Hydraulic brakes conversion was on my 31 Roadster when I bought it , these are sometimes called “Lincoln “ brakes , they are an improvement over the Ford type, as they are self energizing and larger drums . A complete kit runs around $4000. The hydraulic brakes do deteriorate from sitting , had that experience a couple of times when getting cars out of storage. Given the choice, I would have restored the original brake system, they are quite effective if done correctly with shoes matched to drums and mechanical wear is back to factory specs.The Boling conversion is not a “bolt on” some work is required on the rear outer axle and front kingpins to get it to fit.
 
My 29 roadster has 39 brakes on the front and 42 or later on the rear. I have no reason to change as they work quite well as they are. Much better than any mechanicals I have ever had. The limiting factor seems to be the size of the contact between the tire and the road. I run 600 X 16's on the road with both my coupe and roadster. Both stop well but the roadster requires much less leg effort. I wouldn't have put then together with mismatched years, but that's the way it came. Just make sure not to mix years between front and back. If I ever do change them it will be for the Boling Bros. setup.
 
There should be no problem in mixing early and late Ford brakes, the difference is the 42-48's are easier to adjust.

The Lincoln, or Boling, brakes do not have larger drums, and the shoe width and diameter are the same as Ford brakes. They are Bendix brakes so are self energizing and require less pedal pressure than Ford. If you use type 5 (silicone) fluid you should never have any future problems as it rejects moisture where type 3 & 4 attract moisture, resulting in rusted cylinders. I've always run single master cyls., with no problems. A friend recently installed early hydraulics on his A with a dual master and had a lot of trouble getting a high pedal.

Model A brakes require much more maintenance than hydraulics, and may skid the wheels but on long downhill runs will overheat much quicker. Hydraulics were designed for heavier cars than the A, so why wouldn't you go to better brakes?
 
Since this is becoming an opinion based discussion, here is mine.
The mechanicals are just fine. They can sit for years and still work just as well. Hydraulic brakes won't, which might be a problem with winter storage and older drivers.
Anybody that tells you that hydraulics work ten times better than mechanicals has not had a properly redone mechanical brake system. It takes time and money to do it right, and people don't realize that.
 
I can skid my tires with mechanical brakes, altho the equality of hydrolic pressure side to side is one good point.
 
I have 4 A s with mechanical and one with juice brakes I am a real fan of the mechanical brakes just my opinion, if mechanical is done right, you should not have a problem. Your A your choice good luck.
 
Go back to mechanical. The Model A is a light car and if you know how to set up the mechanical brakes they are all you would ever need.
 
I have other old cars with hydraulic brakes. It's a constant battle to keep them working even semi-well in our environment. The A with its mechanicals has been so easy. Simple adjustment, no degradation over winter. My A was fixed properly before I got it so I don't know how much expertise/labor it required but they sure work well.
 
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