Front Brake, Questions

[Werner]

Hello everybody,

the rear axle is finally finished. The service brake works very well. (The tires "whistle".) The parking brake as well, when gently letting it cryes like a freight train with cast iron brake pads ...

Thanks at all for these much help!


Tomorrow I will start with the revision of the front axle. Therefore I already have a question to the front brakes (I will mount the "Floaters"): Among other things, I read in this forum that several "Pills" are used for the front brake application.

I did not understand that. Not the text and therefore not the function. Are these the "Brake Shim Set" (MAC's A2052S)?

Thanks for every hints!

[Will N]

Yes, A2052S at macs are the pills. The function is to correct the length of the operating pin in order to get the 15 degree forward slant on the operating lever. The pills go between the operating wedge and the operating pin.

[Werner]

Thanks for the hint.

This already gives the next question. I hope that my English is sufficient to clarify the question.

When the "A" was constructed, the main load of the brakes was distributed to the rear wheels. Today it is reversed, 2/3 going forward.

I think therefore the basic setting of the brake linkage, as described in the service bulletin, I must change. Front brakes first.

I think that's not only about the adjustment wedges cone, but about the adjusting rods?

I try to explain it this way:

1) The wedges I turn all four back completely.

2) Now I adjust the adjusting rods so that the front wheels first begin to grind. (Now both pads are equally adjacent to the compensators / camshafts.)

3) Now I set the other lining side with the wedges with the square key. (Then the brake pad is full surface.)

Is my question understanding?

[Joe K]

Originally Posted by Werner

Thanks for the hint.

This already gives the next question. I hope that my English is sufficient to clarify the question.

When the "A" was constructed, the main load of the brakes was distributed to the rear wheels. Today it is reversed, 2/3 going forward.

I think therefore the basic setting of the brake linkage, as described in the service bulletin, I must change. Front brakes first.

I think that's not only about the adjustment wedges cone, but about the adjusting rods?

I try to explain it this way:

1) The wedges I turn all four back completely.

2) Now I adjust the adjusting rods so that the front wheels first begin to grind. (Now both pads are equally adjacent to the compensators / camshafts.)

3) Now I set the other lining side with the wedges with the square key. (Then the brake pad is full surface.)

Is my question understanding?

Werner, your understanding is my experience.

In the Model A era, the rear brakes were considered necessary to be somehow "stronger" than the front - and this to prevent a car from swiveling around 180 degrees front to back on panic stop. It was part of Henry's take on "mechanical intuition."

It has been my experience that setting the rear "stronger" causes the rear to slide first and braking - what you get of it anyway - all shifts to the front anyway.

In my experience better to set the front a bit stronger, and cause the rear to "rotate" up until the point where front finally slides on increasing brake pressure. Once you slide and lock the wheels - you're not braking - you're sliding and out of control.

Additionally, on braking with a "heavy front", the action of stopping tends to "push" the front wheels into closer proximity to the pavement. You gain front wheel stopping friction simply by the physics of arresting motion and the location of the center of gravity of the car relative to the front axle.

Think the control advantage of "anti-lock" braking systems. The wheels NEVER stop rotating - even if you TRY to lock them up.

My experience is if the front is "stronger" you 'steer the skid' - which is what most experienced drivers do in a modern car.

One can see this thought in the design of modern automobiles. Front brakes (drums, disks, pads, shoes, whatever) are usually 1/3 to 1/2 again "larger" than rear brake components. Also, front brakes are usually the ones to first wear out. Typical car today needs new brake shoes on the front at perhaps 80K miles. Typical car today needs new shoes on the rear at 160K - perhaps. Some NEVER need them.

Anyway, one take. We have been through this before and others have a different take. Perhaps others have a different driving style?

Joe K

[Railcarmover]

Modern cars bias to the front for better control,that is true..but hydraulic brakes equalize much better than mechanicals.'Floaters"allow the shoe to self energize,requiring exact equalization if you bias to the front.

The 15 degree forward slant of the front brake arms is to have the arm vertical when fully applied for maximum leverage on the brake.

My opinion? correctly maintained and adjusted brakes to Ford standard are more than adequate for safe braking. Floaters are not necessary.

[updraught]

Sponsored Links (Register now to hide all advertisements)

I think he is using these:
https://www.macsautoparts.com/ford_m...-aa-truck.html

Don't think they will self energise like Teds floaters.

[Werner]

Hello everybody,


thank you for the explanations. I meant the balancers, which distribute the braking force a little more evenly on the two brake shoes.

This is not a "self-reinforcement". The self-energizing brake has two requirements: 1) Both brake shoes must be floating. 2) It should be hydraulic brakes, which always have some compensating "preload" on each wheel. Then the brake shoes can accumulate in forwards drive and thereby reinforce themselves. But this is barely manageable with clattering rod brakes.

(In Germany, this brake type was called "Servo" brake. If you had to brake backwards with such a car, you needed more than tripple the pedal force.The idea was good, but not without danger, because the brakes tended to block one way in case of bad setting .) -



But my question is still: HOW the ratio of the F- and R-brakes is adjusted. As described above, adjust the front brake rods straighter?

[Jacksonlll]

The A was designed as a rear skid car. I would stick with that and follow the service bulletins.

[Railcarmover]

By design the car is rear bias. The rear brake levers are longer for a reason.Attempting to bias to the front will greatly reduce braking efficiency and increase the the 'pull' associated with being unable equalize the brakes perfectly with a mechanical system.Ford did rear bias for a reason,with the rear brakes applying first any deviation in front equalization will be barely noticeable to the driver,whereas front bias the effect is immediate.

shims are used,if needed under the between the brake actuating rod and wedge to insure when the brakes are released at rest the lever is 15 degrees forward,so when the brake is applied the lever is vertical.Follow Fords method for adjustment,adjuster screws first,rods second.

[Werner]

Hello!

Thanks for your hints. But I am not sure if I understood everything exactly (language). I use to take the following steps:

1) I set the 4 adjusting rods just as Ford described them in the service bulletin.

2) For the front axle, the free travel of 15 degrees before the 90 degree frictional connection is set with "Pills".

3) With the square, I set the pads to the grinding, then one or two chips back, because the brake pads have already run. All right?

[Werner]

Hi,

meanwhile, the front brakes are ready. But with the rod adjustment I have problems. Does anyone have a hint for the basic setting of the four connections rods? With dissolved wedge setting mushrooms?

Many thanks!

[Will N]

I like to adjust the brake rods so there is no slack in the system, so when you move the brake pedal, all the brake shoes will start to move immediately. In your post yesterday you wrote "2) For the front axle, the free travel of 15 degrees before the 90 degree frictional connection is set with "Pills"." That is not correct, there should be no free travel. You want the front brake levers to lean forward 15 degrees from vertical. But when the brake rod starts to pull back on the lever, it should immediately start pushing down on the wedge to spread the shoes apart.

[Purdy Swoft]

Originally Posted by Will N

I like to adjust the brake rods so there is no slack in the system, so when you move the brake pedal, all the brake shoes will start to move immediately. In your post yesterday you wrote "2) For the front axle, the free travel of 15 degrees before the 90 degree frictional connection is set with "Pills"." That is not correct, there should be no free travel. You want the front brake levers to lean forward 15 degrees from vertical. But when the brake rod starts to pull back on the lever, it should immediately start pushing down on the wedge to spread the shoes apart.

That's the way that I do mine and it works as well as hydraulic drum brakes . This is the setup for the later 29 through 31 brakes that have separate emergency brake system . If any slack or looseness is left in any of the brake rods , the brakes will be very poor . The early brakes are covered first in the service bulletins . The later style that most of the model A's use are covered on a different page in the bulletins . I don't recall the page numbers but maybe someone here can give the info .

[Werner]

Hello Will,


thank you for this statement. I understand it like this: My wife pushes the brake pedal down a bit. And I adjust each individual brake rod so that each steering lever moves immediately and at the same time?

[Werner]

Good evening Purdy,


I have read a lot of you as a braking specialist here in this forum. Often, however, it is difficult to understand, because the translation of the vocabulary is not always unequivocal.

[lotsagas4u]

Don't order any pills, a 4-40 nut works perfect, dab a little grease on nut, insert in top of wedge. Just right

[Werner]

Good afternoon,


the brakes are finally ready. They work very well. In a full braking block the rear wheels. The front wheels with equalizer not.

Should I now adjust the front brake rods slightly firmer (shorter) or better loosen the adjusting wedges at the rear?


Thank you all!

[denniskliesen]

Werner, I set up my brakes first by removing the pins from all brake rods at the end where the rod is adjustable. I get all 4 wheels off the ground, turn the adjusters with the square to take the slack from the shoes. You don't want the brake shoes to drag after this step. Next push back on the lever and adjust the rod turning the adjustable clevis to insert the pin. Make sure by turning the wheel the brakes do not drag after inserting the pin in the clevis and arm. Do that same step on the other wheels.

[Werner]

Hello Dennis, many thanks!



Dennis, I did not quite understand that all.

1) I'm loosening the 4 brake rods from the leverarms.

2) Then I adjust the adjusting wedge so that the brake pads only grind a bit. Then back 1 spike.

3) Where should I push now the lever "back"? In the working direction or at rest end position?

[denniskliesen]

Push the lever back until it engages the brakes. Adjust the rod to insert the pin. If after inserting the pin in the arm and rod end and the wheel drags when rotating then the rod is adjusted too tight. You want to only be able to insert the pin without causing the brakes to drag.