hydraulic brakes

[Jerrybubolz]

I recently acquired a ‘37 fordoor. Previous owner(s) have converted to hydraulic brakes. Looks like ‘39 to ‘48 backing plates. Wheel cylinders, master cylinder,
brake shoes are new. System works VERY, VERY poorly and just barely slows the car down. Brake lines bled numerous times. Pedal is hard, not spongy.
Shoes adjusted numerous times.
What to do? I’ve run out of things to check.
Any help appreciated.
Jerry

[40cpe]

The '39-'40 backing plates have adjusting studs at the bottom of the backing plates, the later backing plates are not adjustable on the bottom pivot. If you have the early backing plates and did not adjust properly it is possible the shoes are not centered in the drums.

Are you using an early style single chamber master cylinder, or a later dual chamber?

[Talkwrench]

It might well be that the linings are undersize and do not fit the drums properly ?

[flatheadmurre]

Look at the linings to start with is the contact/wear just partial...small sector of the shoe ?
If so and its centered you need oversize shoes...if at either end you need to adjust them correctly.
If the contact area is wide and still no stopping power i suspect they put a modern lining material on that is to hard.

[cas3]

1st post, welcome aboard jerry. as mentioned there are two different types of ford hyd brakes, 39-41, 42-48. early has two 11/16 nuts on the bottom for centering the shoes, late has just a welded circular area there for the stud, no nuts. specific adjustments required for the early style. all the above advise is correct, but we need to know what type of backing plate you have, and they take different shoes, perhaps an assembly of wrong parts error?

[cas3]

Sponsored Links (Register now to hide all advertisements)

also, if you have drums off, look to see if stuff has been leaking on the shoes, or way oversize. 12" + 060 is the norm for wear. i cheat a bit, but many i find are waaaaay over that

[mrtexas]

You can try the softer linings. I gave up on Lockheed brakes. Shoes must be arced to the drums or else and adjusted properly. Bendix brakes are SO much easier to adjust and make work correctly. Bendix brakes costs $$ but IMHO worth every penny. The market out there is now for the repro bendix brakes. Lockheed backing plates are pretty un-salable, couldn't hardy give away the ones I had. Metal frisbees IMHO.

[Jerrybubolz]

First of all, thanks to all who have contributed. Work has kept me from replying sooner.
I checked the backing plates this morning. Only two upper brake shoe adjustments. No lower adjustments. No leaks anywhere. Every brake part is new or near new. New 1” bore master cyl. New brake lines, new wheel cylinders... 1 1/4” bore for front and 1 1/8” bore for rear. Brake bleeding done many times. Good stream when valve opens on wheel cylinders. I have had the drums off and reshaped the curvature of the linings to fit the inside of the drums. “MIGHT” have had a slight improvement but mostly negligible.
No expert me but I have restored many vehicles over 50+ years. This Ford problem has got me stonewalled. Any advice much appreciated. The weather here is beautiful and I want to DRIVE the Humpback now before the summer heat sets in.
Thanks to all....... Jerry
[email protected]
480-227-8876

[Charlie Stephens]

JERRY,

Add your general location to your profile, it may pay off. My first thought was is the leverage of the master cylinder conversion correct? Do you know is it ever worked properly? How about some pictures. Good luck.

Charlie Stephens

[TJ]

Have you checked the drums to see if they have been turned to far. It could be that they have been turned beyond the recommended limit.

[1931 flamingo]

What linings do you have??
Paul in CT

[Jerrybubolz]

Paul:
My ‘37 Fordoor is new to me. I did none of the changes on the brake system so I don’t know
what the linings are or where they were made or who supplied them. Jerry

Charlie: I posted two pics of the backing plate and the linkage of the master cylinder of the ‘37 in my “gallery of pics” on the Ford Barn Forum. Also posted a pic of the bracket and parts that actuate the rods to the brake pedal and the master cylinder.All appear to be stock Ford. I am suspect of the way this was “engineered” by some previous owner. I’m new to this site and do not know how to post the pics on this forum discussion. But, I can email or text them to anyone. Thanks, JB

[JSeery]

You can email them to me if you want me to post them. [email protected]

[Bob C]

Doesn't look like the master cylinder is lined up with the push rod, maybe
the picture. Kind of a funky setup.


Bob

[TJ]

That's a set up that appears to not give enough throw to the push rod.

[JSeery]

That is a fairly short throw bellcrank. I would not be a fan of that setup in general. A bellcrank arrangement is fine, but the components used would concern me.

[alanwoodieman]

can you reverse the bell crank? may make a difference . I also would suspect hard linings or old asbestos linings that have become hard, brittle, are there any cracks in the linnings, that would tell if they have been cooked. In the past I sandblasted a set of lings to remove the old hard surface and it really helped

[rich b]

With that bell crank hooked up to the stock mech brake pedal, it may be worthwhile to determine the total pedal ratio. Stock '39 up pedal ratio is about 6-1/2 to 1.

Should maybe have someone (or your cell phone) watch the master cylinder mount when the brakes are applied; looks like is mounted in the X to outer rail brace and those are not very sturdy.

[JSeery]

Guess I can just move them over, LOL. It is just the backing plates, but might be worth having them in the thread. From the bellcrank photo, there does not appear to be a bushing in the pivot, that may contribute to excess foot pressure on the pedal. I would want a bushing minimum and really a bearing at the pivot. Also, as already posted, flex at several places could be an issue.

[Flathead Fever]

Everybody has commented on the possible problems. Before you condemn the brakes for being a dangerous vintage design you need to ride iin another Early Fords to see that these brakes can work decent. Here is another one of my stories.

The first Early Ford brakes I drove was when my Dad bought a '32 Roadster. I drove it home on a 100 degree day, about 80 in stop and go freeway driving. Not knowing what to expec,t at the beginning of the journey I was worried about that flathead getting hot. It has a modifed 8BA in it. It never got over 180 degrees, I was amazed. The temperature worry was soon replaced by the fear of running into the back of somebody. Those brakes were scary in stop and go freeway driving! Twenty-year's later they are still that way because dad never pulled the drums off to investigate. The car never moved so I never had an incentive to go down there and fix it. The steel brake lines are a dangerous mess. I've never looked to see what they did to mount the pedals and master cylinder? I'll worry about that stuff when it comes here to live and I can get it up in the air on the hoist and get a good look at what scary work was done under it.

Everything I had read in hot rod articles pretty much all said the same thing, those early ford hydraulics are dangerous of course they were promoting the brake upgrades of the parts manufacturers that advertised in their magazines. Every time one of those brake stories was published you will just happen to see a large add for the upgrade parts. What a strange coincidence. I had only driven one vehicle with Early Ford brakes at that time. So I started thinking maybe there was nothing wrong with the brakes on the '32 roadster, maybe that's just how they are. The articles had me convinced they would eventually get you killed. If they were as bad as those articles claimed you would think there should not have be a single '39 to '48 Ford frontend that didn't run into something and get smashed.

Then one day I was the passenger in Bernie Couch's '32 Roadster he had owned since around 1937. So I said, Bernie, how bad are these Early Ford hydraulic brakes you have on here are they as bad as everyone says? He didn't say a word and kept driving. I'm thinking that 's kind rude. Why doesn't he answer my question. We had just left stoplight and he was quickly accelerating with the same exact flathead that ran 130 mph at El Mirage around 1950. All of a sudden he stomps on the brake pedal and it
violently threw me hard into the windshield, it hurt! Then he said, "what do you think about them?" That day I realized there was nothing wrong with Early Ford brakes. There was something wrong with the brakes on the cars people were complaining about.

Its no doubt that Bendix self energizing brakes are superior at stopping. But I don't think the Early Ford brakes are unsafe. Also, If your running skinny original tires with a small contact patch on the asphalt your brakes do not need to be any better than the ability of your tires to"not" lockup and skid. Its all about stopping distance without skidding the tires. I'm thinking the self energizing brakes require less pedal effort but the stopping distance is probably close to an Early Ford with original hydraulic brakes and tires. It would be a neat comparison test.

This is something interesting. The required stopping distance of an automobile is the same as it was in the 1930s. I have a bunch of CA vehicle code books. The old ones just have a few pages. You can do just about anything you wanted to a car and still be legal. The new ones are thick as a telephone book, that's if your old enough to know what a telephone book was.

Here is my opinion on Early Ford Brakes. If you can't see them like on a full tendered cara and you drive a lot and your running modern radials the reproduction Lincoln brakes are the way to go. If you don't drive it much I would just keep the Ford brakes.

If its a hot rod, I love the look of those Early Ford backing plates. I would definitely run them on the front. You can stick the Lincolns on the rear where they will not be seen. A lightweight highboy coupe or roadster does not need anymore stopping power than that. I have a Model A roadster pickup with a 324 Olds, a '50 Olds rearend and brakes and the Early Ford Brakes up front. They also used the '50 Olds master cylinder when this car was built in 1950. It will easily lock up the tires and skid with very little pedal effort. This car is what makes me think Lincoln brakes on the rear and Early Fords on the front would be perfect for a period correct hot rod.

If the brake pedal is hard the hydraulics system is good, no air. I don't know who engineer the brakes on this car? Something you need to consider is modifying the original brake pedal and master cylinder setup can change the leverage you are applying to the master cylinder. The pedal length and the rest of the linkage multiplies the force you apply with your foot. If you modify the setup it needs to be designed to multiply the same force as it originally did, like on a '39 Ford pedal setup.

If the brake shoes had fluid on them they do the opposite of what you would think, They lock up very easily. At least they do on self energizing brakes. The fluid causes the shoe to stick to the drum like a drinking glass sitting in water on a table. Its hard to pull off.
If one wheel is locking up the first thing I did was look under the car for fluid on the backing plate. Either gear oil or brake fluid had gottn onto the lining. They cannot be cleaned. I've soaked them in acetone until they looked clean. Then I drove it and took the drum back off, There were little dots of fluid that had come up out of the lining. The other thing as other have said is to fit the shoes to the drums. Its possible your shoes are only touch in the center of the shoes or the very ends. You have to remove the drum and hold the shoe up against it to see how much of the lining is making contact.

You need to make sure the long shoes goes to the front. That is your forward braking shoe. More force is applied to it so it needs to be longer. It is the opposite of the self energizing brakes.

Also,as others have said your brake shoes may not be centered. Axle housing bearing race wear can allow the drum to move up and not be centered with the shoes. The second generation of brakes allowed the shoes to move up and down to center themselves with the drum. Ford advertised this as a big improvement, calling them self-centering brakes. An obvious attempt to confuse people into thinking they were just as as self energizing brakes like all the other manufacturers used.

[Jerrybubolz]

I will check how the MC lines up with the push rod and check for total throw on the rod.
Also see if the bell crank can be reversed and if it changes anything.
Will look at pedal travel for 6 1/2 to 1 ratio.
Also check to see how much, if any, flex in MC mounting and bellcrank area.
I’ve had all the drums off several times. The brake shoes “look” new with no rust and little brake dust and signs of oil, grease or brake fluid spotting. The linings were glazed in spots. As mentioned I did re-curve the surface of the linings to get a better match to the drums. Scuffed entire areas of linings. Used volumes of brake clean to clean linings and drums. I have adjusted all brakes several times with no change. Got them to the point where the wheels would only turn with very firm rotation while on jack stands. They got warm after driving a couple of miles!
Thanks to jseery and others for posting the pics of the backing plate and bellcrank.
Hope to report back to all of you tomorrow morning after inspection.
Many thanks to all who contributed.
Jerry

[JSeery]

To answer some questions on what the original brake systems looked like, the 37 brakes were mechanical brakes using cables. Pressing the pedal down pulled a rod that connected to a center bracket which operated all four cables. When Ford switched to hydraulic brakes pressing the pedal pushed a rod directly connected to the master cylinder (the third image is passenger and 4 & 5 are truck). May be a little difficult to see, but the master cylinder bolts to the same bracket that the pedals are mounted on.

[JSeery]

This is a bit of a guess, but looks like the setup you have may be from pieces from the COE brakes.

[cas3]

i just did this earlier this winter for my 34. it seems that my bell crank is about the same size as the op's 37. to get to this, i figured the full stroke of the pedal to match a full stroke of the master. by driving a nail in a piece of wood and measuring the stroke at various locations when i pivoted the wood, it came up to about 2" (on center) on the pedal end, and about 1.3 on the master, which going by the photo, looks close to the 37 here. car is not on the road yet, so no bragging rights. is there a better way to figure this? not trying to steal the thread, but heres a pic of mine. grease able bushings, supported on both ends.

[Jerrybubolz]

I adjusted the slop out of the rods to the MC and the brake pedal. Now with a LOT of leg pressure, I can lock up the wheels on dry pavement. Still does not perform up to my expectations. Previous owners installed the hydraulic system. Time to get new soft linings, cut the drums and get the curvature of both matched.
Thanks to all who have contributed. Much appreciated.
Jerry Bubolz

[JSeery]

Sponsored Links (Register now to hide all advertisements)

Originally Posted by Jerrybubolz

Now with a LOT of leg pressure, I can lock up the wheels on dry pavement. Still does not perform up to my expectations. Jerry Bubolz

That's what I was assuming from the setup. There is not enough leverage from the pedal, which leads to increased leg pressure to get the required wheel cylinder pressure. A smaller diameter master cylinder bore would increase pressure, but it would also increase the pedal stroke.

[Jerrybubolz]

Jerry:
There is a new 1” bore MC on the ‘37 now. This was added months ago.

[Rusty Karz]

Originally Posted by JSeery

That's what I was assuming from the setup. There is not enough leverage from the pedal, which leads to increased leg pressure to get the required wheel cylinder pressure. A smaller diameter master cylinder bore would increase pressure, but it would also increase the pedal stroke.

There is d definite formula regarding M/C size and the wheel cylinders. I put an incorrect one on an MG TD and got a very hard pedal and very little stopping power. A correct M/C corrected the problem. Unfortunately I don't remember the formula as it was years ago. Might be worth looking into.

[Jerrybubolz]

My only reference to MC and wheel cylinder bores is from the Dennis Carpenter
Ford Restoration catalog. Here’s what is on my car.

MC 1” bore (Carpenter catalog says MC rebuild kit is 1”)
Front wheel cylinders 1 1/4” bore. (Carpenter catalog says 1 3/8”)
Rear wheel cylinders 1 1/8” bore. (Carpenter catalog says 1 1/8”)

What bores would be the most correct for ‘42-‘48’ brakes? Does the
1/8” inch difference for the wheel cylinders on the front axle make a
difference?
Jerry

[flatheadmurre]

Isn´t the std master cylinder 1 1/16" ??
And front 1 3/8"-1"
Smaller master should give you less pressure on the pedal for same system pressure...but at the same time your smaller diameter wheel cylinders are working against you.
As it´s set up now you have less braking power on the ffront axle then as designed from start.

[Jerrybubolz]

Originally Posted by flatheadmurre

Isn´t the std master cylinder 1 1/16" ??
And front 1 3/8"-1"
Smaller master should give you less pressure on the pedal for same system pressure...but at the same time your smaller diameter wheel cylinders are working against you.
As it´s set up now you have less braking power on the ffront axle then as designed from start.

The specs I quoted were from the Carpenter catalog. They seem very knowledgeable people.
In a perfect world, what would be the optimum specs for the MC and for front and rear axle wheel cylinders?
Thanks, Jerry

[JSeery]

Originally Posted by Jerrybubolz

Does the 1/8” inch difference for the wheel cylinders on the front axle make a difference? Jerry

What makes the difference is the surface are of the pistons. Might help you to look at some articles on brake mechanics.

http://www.bullbrakes.com/Technical_...ke-System.html

http://www.peterverdone.com/archive/...m%20theory.pdf

There may be way better articles, these are just from a quick search. There are whole books on the subject!