Brake Lining

[31 RPU]

Just got a set of brake shoes and they have the non woven linings on them and are glued with no rivets? Are these ok? An old timer told me that the woven are the best. I am using these with cast iron drums.

 

[Mitch//pa]

i prefer and only use the riveted woven linings.. the bonded shoes you have will not dissapate heat the same causing cracking and hairline cracks which can lead to noises, and at times glue separation along with uneven braking//grabbing. with that being said some have used them with no issues also

 

[Joe K]

With cast iron drums they'll work fine - just like modern cars.

Hey, wait. Modern cars use disks and not drums don't they?

Joe K

 

[31 RPU]

A lot of modern cars use disk on the front but the fronts do most of the stopping and use drums on the back.
The Model A is opposite so should I use woven on the rear and bonded on the front?

 

[Joe K]

In theory you're correct IF you want to go to a pressed drum on the rear. IMHO, the woven linings are better (more grabby) than all other linings given a drum system.

If I had to put the brake systems in order of efficacy, I would order them this way:

Woven linings - cast iron drums
Bonded linings - cast iron drums
Woven linings - pressed steel drums
Bonded linings - pressed steel drums

There is some conjecture in this as I have not tried all of these on my Model A. (I'm currently with woven linings and original pressed drums.)

But one has to be careful in this examination and NOT take this as one being superior over the other. For a Model A with it's mechanical brakes, it's all in how you "set up" the brake system.

I generally like to have my Model A a bit tighter brake-wise on the front. I want the brakes to grab on the front BEFORE the rear wheels. This matches the "tilt forward" dynamic of the action of stopping and puts the most decelerating counter force between the front wheels and the road. (And the reason for ABS in modern cars which bring all four wheels to that "sticky" condition point simultaneously.)

And, OBTW, this the reason that pre ABS "modern" cars have disks on the front and drums on the rear - it's an attempt by the car maker to bring earlier brake action to the front. Back in the day of drum brakes all around this would be done by larger brake wheel cylinders on the front. Now with computer controlled ABS it's not so important as the computer figures that point and makes it happen according to wheel rotation.

This "forward stronger brake" modus is the exact opposite of how Ford instructed the brakes to be set up for the Model A - Ford seemingly assuming he wanted the rear to "grab" first and prevent the car from swinging around 180 on application of brakes.

But Ford did not anticipate driver action to "steer" the skid which we all do instinctively once we as drivers have a few miles under our belts. (Beginning drivers learn this quickly - and one thing that separates a teen driver from the more experienced.)

One has to be careful because via brake adjustment, one can optimize ANY of these systems named above. The optimal point being, of course, just before where the tires skid on the pavement, and preferably the fronts.

Any additional braking beyond that point is irrelevant - and given the adjustment ability afforded by mechanical brakes - THEY are possible to give superior stopping power compared to a hydraulic conversion - providing the mechanical are kept up adjustment wise.

Correction on that - hydraulic brakes CAN be adjusted. At least the 1937-1951 version I've seen - they just need adjustment less often. Also they're design intended for a car perhaps half again as heavy as a Model A - and for the Model A not an optimal braking system

Hope this helps. Just keep in mind - once skid begins - braking is DONE. It's the action UP TO that point which makes a difference on how quickly you can stop the car.

Joe K

 

[Kevin in NJ]

Ford switched to composition brake shoes before the end of production. It was riveted on and more of a grey color. If I remember correct the switch to composition came before the switch to cast drums. Ford then sold composition lining in the aftermarket.

So what works best?

Properly installed, properly centered, and properly arched to the drum linings. Of course, you have properly put the rest together with new or NOS parts and corrected various bend and wear issues and have tight pins going into the shoes.

Best if you can find a local guy with a Barrett Brake Doktor that sands the shoes center and to the correct size on the axle.

 

[700rpm]

I set my brakes up to grab in the rear first, then the front. The woven linings are better for mechanical brakes, regardless of whether they are cast iron drums or not. My philosophy is Henry had the best engineers of the time working for him, and they designed the various systems in the Model A as systems that work together, not as individual components that could be changed out without regard for how the system was designed. I believe that's why guys have trouble with their cars when they make modern "improvements" and unnecessary changes and additions, and that's why I keep my cars all stock, except for concessions to safety like glass, rh tail light, seat belts and turn signals.

 

[Joe K]

and that's why I keep my cars all stock,

And I imagine you've never had an instance of your car going "180?"

Unlike me in my 1986 VW Golf on Route 95 North in the middle of a snowstorm and suddenly finding the front locked up and the car making a 180 in the middle of the highway.

I was lucky - careful steering of the skid brought the car a full 360 and I caught it just as it was "realigned" with the road.

Be still my heart just thinking about it.

But the event does indicate the validity of Henry's thinking IN THAT SITUATION and under those circumstances. And the failure of non ABS disk fronts and drums rear.

Modern ABS brakes would have compensated directly and likely I would never have gotten outside my comfort zone - or known there was an issue with adhesion with the road. Well, except for that thump-thump-thump sound of the ABS pumping the brakes.

But no brake system, even ABS, is optimal for EVERY braking circumstance.

Joe K

 

[Bob Bidonde]

In the 50 years I have been in our hobby, I have not seen or heard of any reports of brake failures brought about by woven or bonded lining materials, or by riveted and bonded applications.

Cast iron on woven brake lining has a static coefficient of friction = 0.35 to 0.40, and
steel on woven brake lining has a static coefficient of friction = 0.22. Cast iron also has a better heat transfer coefficient than steel. Considering the coefficients, woven brake lining is better with cast iron than it is with steel, and overall cast iron is a better brake drum material. This explains one reason why automakers went away from pressed steel brake drums in the 1930s. Clearly, the ease of manufacturing cast iron drums is a cost advantage over pressed steel drums.

From about the 1860s to the 1930s, woven brake lining ruled the market place because it was producible by the weaving manufacturing technology of the time period. However, as more modern chemistry came along in the late 1930s, molded linings became less expensive to manufacture.

Asbestos found its way into woven linings and early molded linings which would bring about their eventual demise. However modern chemistry adapted space age ablative materials into molded linings, so they have survived.

Brake technology as a whole was driven by the aviation industry that had to cope with heavier aircraft and higher landing speeds. Imagine the brakes it took to stop a WW2 era B29 Bomber!

 

[Patrick L.]

In the 50 years I have been in our hobby, I have not seen or heard of any reports of brake failures brought about by woven or bonded lining materials, or by riveted and bonded applications.

Cast iron on woven brake lining has a static coefficient of friction = 0.35 to 0.40, and
steel on woven brake lining has a static coefficient of friction = 0.22. Cast iron also has a better heat transfer coefficient than steel. Considering the coefficients, woven brake lining is better with cast iron than it is with steel, and overall cast iron is a better brake drum material. This explains one reason why automakers went away from pressed steel brake drums in the 1930s. Clearly, the ease of manufacturing cast iron drums is a cost advantage over pressed steel drums.

From about the 1860s to the 1930s, woven brake lining ruled the market place because it was producible by the weaving manufacturing technology of the time period. However, as more modern chemistry came along in the late 1930s, molded linings became less expensive to manufacture.

Asbestos found its way into woven linings and early molded linings which would bring about their eventual demise. However modern chemistry adapted space age ablative materials into molded linings, so they have survived.

Brake technology as a whole was driven by the aviation industry that had to cope with heavier aircraft and higher landing speeds. Imagine the brakes it took to stop a WW2 era B29 Bomber!

I've tried to find the COF figures for quite some time. Didn't look hard enough I guess .
Its nice to see those figures, but, have you found the same for molded/bonded linings ?

 

[Y-Blockhead]

I generally like to have my Model A a bit tighter brake-wise on the front. I want the brakes to grab on the front BEFORE the rear wheels. This matches the "tilt forward" dynamic of the action of stopping and puts the most decelerating counter force between the front wheels and the road.

Joe K

Joe, Thanks for the post. Ever since I bought my '30 Town Sedan ~3 months ago and read how to adjust the brakes I have been thinking about this.

When I read the procedure for adjusting it just didn't make since to "adjust the rears to lock up first"? (Not that you want them to lock up at all).

I did adjust the fronts a little tighter and, to me, it seemed to stop quicker.

Thanks for confirming my thinking and I'm not nuts (completely anyway)

 

[Joe K]

Thanks for confirming my thinking and I'm not nuts (completely anyway)

Thinking this out a little further, the difference between the four options I provided above (listed in decreasing levels of adhesion/coefficient of friction between lining and drum)

Woven linings - cast iron drums
Bonded linings - cast iron drums
Woven linings - pressed steel drums
Bonded linings - pressed steel drums

The difference is in the amount of pedal pressure required with woven linings and cast iron drums being the least pedal pressure. (and least fade)

BUT - and here is the downside - woven linings WEAR quicker than bonded linings - have a shorter life overall, and require more frequent adjustment.

But you get brakes with more "sensitivity" - which translates to more braking control - and perhaps less tendency to grab and skid the wheel which results in a complete loss of control.

Remember what I said above? Once you skid - you brake no more. The trick in brake systems is to have everything within command of the operator such that he can bring it to the point of skidding - but only slightly less. And IMHO, the most control results with woven lining and cast iron drums.

Which is where I will be when the brakes get re-done.

I have the Scandinavia linings already...

Joe K

 

[Dick Carne]

For what it's worth, I originally used the woven linings with some of Mel Gross' new cast iron drums on our fordor, but after a few hundred miles, switched to bonded linings on the brake shoes - these seem to stop much better with this set-up. Just before switching, it was almost as though I had no brakes at all. I'm much more satisfied with the cast iron drums and bonded linings. With that said, I once tried the bonded linings with steel drums - I would strongly recommend woven linings for use with the original steel drums for the same reasons - just the reverse. Good luck to you whichever route you choose to take.

Dick

 

[Vic in E-TN]

I saw some information a long time ago on molded lining coefficient of friction. There are several grades defined by a letter. I do not remember the sequence - A to M perhaps. If you have a good brake/clutch shop in your area you can ask them to bond some new linings to your shoes. Some years ago I sent a set of shoes to a shop in Minnesota and they bonded the "softest" - highest COF to my shoes. They seem to work well but I have less than 100 miles on that car. If you want to take your "modern" car to a franchise brake shop that gives "lifetime" warranty on the discs/shoes you can be fairly certain that you will get the hardest friction material that has the lowest COF available. My experience with modern Ford discs on new vehicles is that you are lucky to get 30,000 miles on them but they stop well.

Engineering a brake system is a chore.

My choice of drums and lining material is to go with Mel-Randy Gross drums and their molded-bonded material. I have several years of good luck with them.

Vic

 

[Pete]

Someone said bonded lining does not dissipate heat as good as riveted lining.
That is wrong information.

A little side info on stopping distance with different lining/drum combinations.
It does not matter what you have for brakes as long as they will lock up and are properly balanced, you can shorten your stopping distance in a crash situation by 5 feet at 30 mph by modulating. (any race driver knows this)
Also in a "tense" situation such as an impending spin, you will have better control of the car if you keep the throttle on some while braking.
Ever wonder why sprint cars can go all the way around the track without lifting the throttle?? (they are steering with the brake dragging)

 

[Mitch//pa]

great discussion