Woven brake linings and Cast Iron drums

[robgross1930]

Originally Posted by Synchro909

A guy in our club has this combination and says that the linings are tearing up his cast iron drums. He thinks the brass threads in the linings is scuffing up the drum too much and wearing them out quickly.
Does anybody have any experience on this?
Note: Experience cannot be gained from an armchair.

With all due respect, that fellow is a little misinformed in my opinion. Woven lining is soft and is still soft with brass. Soft woven linings are made specifically for "mechanical" brakes irrespective of the drum material.

[Synchro909]

Originally Posted by robgross1930

With all due respect, that fellow is a little misinformed in my opinion. Woven lining is soft and is still soft with brass. Soft woven linings are made specifically for "mechanical" brakes irrespective of the drum material.

That has been playing on my mind too. That's why I thought I would ask about it here. That said, the original mechanical brakes of the day all (as far as I know) all used steel drums.
When did they change to bonded linings and when did they (car makers) stop using steel drums? Did those two things happen at the same time and if so, was it because they encountered the same problem as my fellow club member?
Put another way, did car makers use woven lings with cast drums?

[robgross1930]

Originally Posted by Synchro909

That has been playing on my mind too. That's why I thought I would ask about it here. That said, the original mechanical brakes of the day all (as far as I know) all used steel drums.
When did they change to bonded linings and when did they (car makers) stop using steel drums? Did those two things happen at the same time and if so, was it because they encountered the same problem as my fellow club member?
Put another way, did car makers use woven lings with cast drums?

Bonded lining means bonded to the shoe using a bonding process that uses a special adhesive. The solid looking linings, as compared to woven, are “molded” linings. Some molded linings are bonded and some are riveted. I have also seen woven linings that were bonded and of course riveted which is what we like for Model A’s.

The softer the lining material, the greater the coefficient of friction. Ford made a “soft” molded lining, I think about 1932 or so, maybe later, that had a greater coefficient of friction than the typical “hard” molded lining. The woven lining, being soft, has a higher coefficient of friction.

There are only a few things that one has to really consider: the type of brake system and the pressure it’s capable of applying and the coefficient of friction of the type of lining used. A brake system that has a weaker applied pressure, i.e., mechanical brakes, requires a soft lining that creates more friction, such as woven, to have the best brakes with that type of system. A brake system that has a strong applied pressure, i.e., hydraulic brakes, needs a harder lining with a lower coefficient of friction, such as a hard molded lining. If a lining with too high of a coefficient of friction, such as woven, is used on hydraulic brakes, the brakes can grab or lock up. On the other hand, a hard or harder molded lining used on mechanical brakes will not supply enough friction relative to the pressure applied on the shoes, and the brakes will be poor as compared to woven linings.

[Kevin in NJ]

Originally Posted by robgross1930

Bonded lining means bonded to the shoe using a bonding process that uses a special adhesive. The solid looking linings, as compared to woven, are “molded” linings. Some molded linings are bonded and some are riveted. I have also seen woven linings that were bonded and of course riveted which is what we like for Model A’s.

The softer the lining material, the greater the coefficient of friction. Ford made a “soft” molded lining, I think about 1932 or so, maybe later, that had a greater coefficient of friction than the typical “hard” molded lining. The woven lining, being soft, has a higher coefficient of friction.

There are only a few things that one has to really consider: the type of brake system and the pressure it’s capable of applying and the coefficient of friction of the type of lining used. A brake system that has a weaker applied pressure, i.e., mechanical brakes, requires a soft lining that creates more friction, such as woven, to have the best brakes with that type of system. A brake system that has a strong applied pressure, i.e., hydraulic brakes, needs a harder lining with a lower coefficient of friction, such as a hard molded lining. If a lining with too high of a coefficient of friction, such as woven, is used on hydraulic brakes, the brakes can grab or lock up. On the hand, a hard molded lining used on mechanical brakes will not supply enough friction relative to the pressure applied on the shoes, and the brakes will be poor as compared to woven linings.

Could you please give references to prove what you have stated?

I am not saying you are wrong. I do not know for fact about some of what you have stated above.

What is the friction ratings of the linings? Where is this written?

What says the hydraulic brakes are applied harder then mechanicals in the same application?

Where does the idea that you need harder linings for hydraulic brakes vs mechanical brakes and how does it translate to the Model A/ V8 brakes?

Again, I am not trying to be a smartass or trying to disprove you. I do not know if what you said is true or false and want to see it for myself in reliable documentation.

What you say may seem to have intuitive sense, but I like to back up intuition with data. True data about the brakes system on the A has been difficult to find. I have bought some early manuals and other documentation in hopes of getting hard fact and have not found much about various brake issues that I have questions about in my mind.

Thanks

[robgross1930]

Originally Posted by Kevin in NJ

Could you please give references to prove what you have stated?

I am not saying you are wrong. I do not know for fact about some of what you have stated above.

What is the friction ratings of the linings? Where is this written?

What says the hydraulic brakes are applied harder then mechanicals in the same application?

Where does the idea that you need harder linings for hydraulic brakes vs mechanical brakes and how does it translate to the Model A/ V8 brakes?

Again, I am not trying to be a smartass or trying to disprove you. I do not know if what you said is true or false and want to see it for myself in reliable documentation.

What you say may seem to have intuitive sense, but I like to back up intuition with data. True data about the brakes system on the A has been difficult to find. I have bought some early manuals and other documentation in hopes of getting hard fact and have not found much about various brake issues that I have questions about in my mind.

Thanks

You obviously have no experience in tribology and its relation to industrial friction material. So I'll leave it at that.

[Kevin in NJ]

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Originally Posted by robgross1930

You obviously have no experience in tribology and its relation to industrial friction material. So I'll leave it at that.

While I am not familiar with the study of Tribology I have an understanding of physics. There are quite a few sub-fields and that was not the field I followed.

Do you have useful information that you could share on the subject as it relates to the materials used in the Model A brakes both past and present?

Can you educate us? I am asking for information here, I seriously would like to see some fact based information that relates to the materials used in the Model A. This is exactly what I want to know.

Clearly we would need to see some graphs of the materials for todays materials and the ones Ford used.