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Thought this might be considered ancectodal evidence, I must say that I drive, on a daily basis, a vehicle equiped with hydraulically-actuated, four-wheel drum brakes, of the dual-servo, self-adjusting type. Since re-shoeing all four wheels several thousands of miles ago, I have, in a wide variety of braking conditions, experienced no brake fade. Could it be the modern linings?
I also wish to point out that the brakes lack power assist, which the servo action seem to make up for, and, that braking control driving on ice and snow was much better than what I have experienced on ABS and non-ABS power-assist front disc/rear drum equiped vehicles.-WK-139.78.96.115 01:13, 8 March 2007 (UTC)
Yes, it is a 1968 Chevrolet truck.-WK-139.78.96.83 22:23, 20 March 2007 (UTC)
References
I hope you can accept what I have done to your "brake fade" page. Having worked on disk brake development and working with tribology (friction and wear) I came across the items I mention in the rework of that article. The gas bearing and drum expansion are things mechanics, not engineers, cooked up and it is obvious because servo effect is not part of their technical understanding. Jobst 06:40, 17 February 2007 (UTC)
I think you should re-read what I wrote and tell me what part you don't understand. The article as it was is based on myth and lore, that you cite from a popular magazine. That is not a valid citation, only a repetition of what you have repeated. I explain why the gas bearing hypothesis is false and defies all reason. Having worked on disk brakes in high performance cars from the outset of disk brakes I can explain how this works and did so. If anythinng, you should show proof that expanding drums and gas-bearing exist. As I mentioned, disks operate at red hot temperatures, ones that gas bearing drums never did, using similar friction material. You should also consider why drums were discontinued when friction materials that cannot out-gas have been designed. Jobst 03:39, 18 February 2007 (UTC)
I don't understand what you mean by "you are not the source". The part that you offered is documented more sparingly than mine and as I pointed out, defies physics. That is why it caught my attention. You refer to WP:PILLARS in which is stated:
That you restored the old version seems to indicate that you believe it is correct. I suggest that you give proof that drum expanding or gas bearing causes brake fade. The references listed are not technical support for this physically impossible hypothesis. If you are skilled in the design of brakes you shoudl recognize what the downfall of drum brakes is and why we no longer have brake fade. You shouldn't take this personally and feel insulted but you should also not pass on folklore as encyclopedic information. Jobst 04:25, 18 February 2007 (UTC)
Please check out the links! I did not say that you are not "the source"; I said that you are not "a source. Please see WP:RS. I welcome your editing here but not if you are disregarding the rules and presenting your unsourced theory and discarding sourced material. I do not have to "prove" anything to you The burden of proof is on you and the only acceptable proof is WP:RS. Nothing personal. Thanks --Justanother 04:38, 18 February 2007 (UTC)Wikipedia is an encyclopedia incorporating elements of general encyclopedias, specialized encyclopedias, and almanacs. All articles must follow our no original research policy and strive for accuracy; Wikipedia is not the place to insert personal opinions, experiences, or arguments.
To make the point that you are repeating auto lore, I have asked for references on a few of your unsupported claims. Alternately you could explain how these things occur and their cause instead, but you do neither. Especially the gas bearing item needs explanation or proof, that being a lot of gas with no apparent source. Remeber, after cooling, faded brake pads show no sign of having lost gas or otherwise changed permanently. In fact, they will do it again if put to the test.
Please give what I wrote some thought. Also your talk of high performance equipment has nothing to do with the causes and remedies of drum brake fade. Jobst 05:04, 18 February 2007 (UTC)
As you see, justanother, the anonymouse author of this piece, shows no reasonable explanation for the effect of brake drum expansion causing fade, the Coefficient of thermal expansion being vanishingly small in comparison to normal ovalization of drums by braking forces. The gas bearing scenario cannot be found in Dunlop, Girling, Lockheed or any other brake manufacturer's literature. It is folklore. The volume of gas required for such an effect cannot come from friction material, once or repeatedly, brake fade occcurring again as easily as the first time. The citations listed are auto enthusiat magazines, neither of which explain what these gases are and how they keep coming out of brake pads that were originally formed at high temperature in manufacture.
Brake fade is unique to drum brakes because they use self servo action (leading brake shoes) [[1]] whose servo effect relys on the proper friction coefficient, one that reduces at elevated temperatures. I request that justanother cease deleting my re-write of this article and not continue purvey myth and lore. Please note the [citation needed] notations in the article. Jobst 18:31, 19 February 2007 (UTC)
Dear justanother,
Deleteing [citation needed] callouts in your article is not the way to respond to requests for verification of what is known by people in the indstry to be myth and lore. Jobst 19:15, 19 February 2007 (UTC)
justanother, I beg to differ. Having worked in the disk brake business I am aware that these folklore stories of gas are some sort of widely believed cargo cult, even though there is no credible explanation, nor any analysis of its existence. You won't find a technical source for proof of the gas bearing or brake drum expansion theory. On top of that, not much is being written on drum brakes these days, except the repition of the gas theory. Please review what I wrote and the proof I gave about drum brakes operating in a narrow friction coefficient between lock-up and fade. How does the gas hypothesis explain drum brakes locking? Jobst 20:07, 19 February 2007 (UTC)
Maybe I'm unclear on the concept, but who is entitled to place [citation needed] references in articles? From my experience it seems to be as open as the rest of Wiki. One of my previous articles was riddled with them even where there were plenty of references. After that the article was deleted by I don't know whom although I can guess from the threats that preceded.Jobst 00:03, 20 February 2007 (UTC)
Justanother, the only thing you really need to do is stop writing unsourced material. If you add something then provide a source so that othere editors can check your work. That is how it works here. If you will do that then you will find that your contributions are welcomed here.
That your article is backed up mainly by another's repetition of drum brake
lore does not seem to stike you as odd. That citation contains no explanation of what causes fade, only that it is caused by thermal expansion and gas generation, both of which have not been shown to exist. This is a hypothesis from brake mechanics, not an engineering staff at a major brake manufacturer. Repeating it from auto magazines does not make it credible. We don't need Wiki's to repeat such stories when you can get that from the man on the street.Jobst 03:37, 20 February 2007 (UTC)
I am restoring your destructive edit again. Please contribute sourced material instead of removing sourced material that you disagree with. Disk brake fade is a reality. The 1959 reference had it wrong but can be forgiven for that. We know better now --Justanother 19:11, 20 February 2007 (UTC)As the brakes get hot the drums expand away from the shoes and the pedal travel increases. The friction coefficient of the hot linings drops and finally the brakes fade.
Whether it is your article or not, you seem to be its sole defender and thereby assume authorship. Bluntly, it is erroneous and false. Apparently you didn't read the referenced study in which among other findings the following is mentioned:
By reinstating your brake folklore article you ignore logical explanations that should have dissuaded you from the belief in the drum expansion and gas bearing hypotheses, neither of which are physically possible. Editing and elaborating on these fables does the readers of Wiki a disservice. This is not a forum for myth and lore. You have shown no explanation how drum expansion and gas bearing cause fade or that they do so. What I wrote, as well as in the reference citiation from a scientific journal explains how the servo effect of drum brakes causes brake fade.
Is there no one else reading thse pages with comments on the subject? Jobst 20:49, 20 February 2007 (UTC)
You say you are not the author but you expanded the article to have more sections, mostly not about brake fade and its cause. Since the introduction of disk brakes, more than 30 years ago, fade has no longer been a concern to drivers, making the other parts of the article irrelevant.
A single Brake Fade heading will do, fade being unique to drum brakes and its cause their servo effect. My article recalls the vagaries of servo effect that cause both fade and lock-up. I don't see what part of the existing article you propose to keep.
The report I cited appeared in a peer reviewed Michigan State University technical publication. Your ad hominem of the author is out of place. This is not an auto magazine with conversational fare.Jobst 22:27, 20 February 2007 (UTC)
"Brake fade - There are many types and causes of braking fade. Fade may result, for example, from a reduction in friction between linings and drums caused by exposure to water. Most typically, however, fade involves a reduction in braking force experienced when dragging brakes on a long grade. If brakes are maladjusted, and overheated drum may expand to the degree that push rod travel is insufficient to fully actuate the brakes. This is one example of mechanical fade, which also may result from various mechanical defects (e.g., scored drums) within the foundation brake system. In contrast, heat fade occurs when linings overheat and become less aggressive. Gradual and predictable fade is desirable as a warning."[3]
"At Bendix Spicer Foundation Brake, we developed the metallurgy in our 17-inch rotor and paired it with our advanced friction material specifically designed to optimize friction performance at high temperatures, thus significantly reducing brake fade and maximizing brake pad and rotor life. As a result, there is virtually no degradation in stopping power when brake temperatures rise under heavy use."[4]
Also fade in clutches! Note: these are quotes to point to sources, not for inclusion directly. --Justanother 14:37, 21 February 2007 (UTC)
Lots of great data, esp. on "fluid fade".[5] --Justanother 14:46, 21 February 2007 (UTC)
Justanother, you suggest:
"Jobst, that is a great reference and I wish that you would use it to improve the article rather than to abuse the process here. It is clear from the article that friction fade is a factor on disk brakes and that Bendix has claimed to made a breakthrough to reduce it. Good for them! The issue of fluid fade is not addressed because Bendix is not selling brake fluid in that ad. --Justanother 13:34, 21 February 2007 (UTC)"
Thanks, but how do I merge this with the current article, there being a conflict about the definition of fade and its cause. As I mentioned in my article, friction coefficient is affected by temperature, a change that is magnified by servo action of drum brakes, the bane of vehicles descending steep roads. I believe that loss of hydraulic stiffness between pedal and brake pad should not be called fade. Power assist brakes bridged most of that effect. Fade, as I see it, occurs at the friction interface. As Bendix mentions: "Virtually no brake fade and no degradation in stopping power." is not the fade phenomenon of drum brakes, but a reduction in brake response that is effectively imperceptible. As mentioned, disks work well even at glowing temperatures.
From the beginning of this discussion, the concept of thermally expanding drums and gas bearing was what I believe should not be endorsed in Wikipedia. What I wrote addressed those issues so how do I get my text together with yours without apparent contradiction? I would like to submit what I currently have so you can indicate which parts you believe need modification. I find appending it to the current Brake fade page illogical. I also believe that brake fluid effects should appear under a separate heading of mechanical brake degradation as Bendix does, because otherwise it clouds the issue of resolving what makes drum brakes (friction) fade prone.Jobst 18:46, 21 February 2007 (UTC)
I'm unclear on where you mean. Do you want me to write that in this discussion page or on the Brake fade page? I notice there is a [citation needed] in that subject, here and on the Brake fade page. Also the section above that title, Causes of brake fade leaves a dilemma in that it states the gas bearing and expansion effects are the cause. Please explain.Jobst 20:00, 21 February 2007 (UTC)
In the case of drum brakes the change in dimension of components in response to heat; the curvature of the brake shoes then failing to match the curvature of the brake drum[citation needed].
In light of reading all of your comments in respect to this article, I would suggest taking a look at Requests for comment (RfC). I was also going to suggest taking a look at WikiProject:Automobile construction but it appears to be inactive. (It may be of some use though). I hope I was able to help. Happy editing! Johann...[ T...C ] 00:21, 22 February 2007 (UTC)
Jobst: How do you justify this statement:
Fade was commonly attributed to thermal brake drum expansion, reducing brake shoe contact with the drum. This ignores how little expansion a hot drum experiences, (about 0.024 inch for a 400°F temperature rise) far less than normal deformation caused by brake shoe pressure.
when it conflicts with Bendix
If brakes are maladjusted, and overheated drum may expand to the degree that push rod travel is insufficient to fully actuate the brakes.
Admittedly, adjustment is a major factor, but you cannot simply discard this as "myth"?--Justanother 02:14, 22 February 2007 (UTC)
BTW, Jobst, this is a bit outside our scope here but you might find it interesting. http://fmr.korea.ac.kr/korean/research/results/en25.pdf --Justanother 02:33, 22 February 2007 (UTC)
I found interesting that there was no truck drum-brake fade mentioned in these papers although they measured fade of brake materials. The failings of the drum brake seem longer to be studied since passenger cars switched to disks.Jobst 18:44, 22 February 2007 (UTC)
I don't see anything in the Bendix page contradicting what I wrote, consdering that the drum expansion that I chose at glowing hot temperatures giving 0.012" per shoe is insignificant in comparison to drum ovalization under hard braking. We may be putting the cart before the horse in requireing citations for everything stateded. If that were necessary there would be no text and only links to other places. I believe that only if the item is not reasonably credible other justification needs to be cited. Do you believe 0.012" is enough to prevent brake pads from making contact? You are probably aware that unless the contact area is severely compromized, applied force and friction coefficient, independent of contact area, give the drag force? Such considerations need to occur when reading descriptions, otherwise an entire high school physics book would need to be referenced, not to mention higher mathematics and college physics. I believe there is no comflict between Bendix and "Fade in drum brakes" because the "push rod" mentioned is found only on truck air brakes. I also don't believe this Bendix brake is intended for tandem dual axles but mainly for front truck axles judging from the size of its lug bolts.Jobst 06:01, 22 February 2007 (UTC)
By the way, I do not understand who is supposed to delete [citation needed] inserts in an article. I deleted the one in "Fade in drum brakes" but don't know what the procedure is.Jobst 06:08, 22 February 2007 (UTC)
Could you be more specific? I found no reference to [citation needed] nor who is entitled to inset or remove that flag. I read through a lot of verbiage without making any headway. Could you explain it or give a specific pointer to a description.Jobst 00:26, 23 February 2007 (UTC)
((expert))
Or
((Inuse))
I hope I was of assistance. If you ever need help, feel free to contact me. Happy editing! Johann...[ T...C ] 00:57, 23 February 2007 (UTC)
That page did not make this clearer. It stated that "if everyone agrees the 'fact' template can be remoced"... but by whom and how do I know everyone agrees? The same goes for the two boxes above. I am unclear on how to invoke a spell checker in Wikipedia so I often write on a word processors elsewhere and cut and past. As I wander around in this maze, I begin to feel that I backed into a secret handshake club that wards off newcomers with a depth of procedures. For instance the form of the above paragrafh, seen in edit mode, is utterly cryptic.
What I found difficult was the subjects on which I wrote were themselves unsourced, but when challenged relied on common knowlege that made citations unnecessary. That makes rewrite of aricles diffcult, being held to a different standard than the original article that doesn't disagree common knowlege, regardless of validity. I am glad user:Justanother has been gracious in allowing space on his article for a different assessment of the subject, one that I feel needs to be heard. Both car brakes and engine valve drive are areas in which I worked extensively when these subjects were first subjected to scientific (computer) analysis ca 1960...).Jobst 03:58, 23 February 2007 (UTC)
You can simply ask all editors currently involved in this article to say either 'yes' or 'no'. I understand that some of the code used in writing articles is somewhat confusing, but it may relieve you to know that the majority of the above text is my signature. (In my note that is). Also, 'Justanother' does not have ownership over this article; it is stated below the edit window that "If you don't want your writing to be edited mercilessly or redistributed by others, do not submit it" and also "You agree to license your contributions under the GFDL." I hope this has clarified a few things. Happy editing! Johann...[ T...C ] 01:44, 24 February 2007 (UTC)
I have decided to set up a vote here:
This vote is to decide if we should keep the [citation needed] notes in this article. (0/1/0); Scheduled to end 01:40, 2 March (2007) (UTC)
Please keep comments constructive and polite. Thank you.
Type # '''Support/Neutral/Oppose''' ~~~~
Support
Oppose
Neutral
Keep this article: There is a lot of information specific to various brake fade mechanisms that is worthy of its own article. Dan Schwartz, Cherry Hill, NJ; Expresso@Snip.Net
Comments
I am unclear on what "Oppose" and "Support" mean. I am opposed to deleting the sections but I support verifying that gas bearing or drum expansion are causes of brake failure. There has been no technical explanation of these phenomena. People not in the brake design business have repeated them so often that proof by repetition seems to have been achieved. I referenced thermal expansion coefficient and its effect and pointed out that enough gas to float brake shoes is inpossible to generate repeatedly from friction material that shows no material change between incedents of fade and no loss of performance when cooled. Effects of self servo are found in mechanical and electical journals apenty and that the drum brake relies on this to function. My reference to the Michigan University article links servo to the problem unambiguously. Unfortunately there are so few cars with drum brakes that we no longer experience this. Disks have been here so long that no one publishes drum brake research today. Jobst 23:01, 25 February 2007 (UTC)
I see no [citation needed] tags that I placed. This is getting more cryptic with each turn. The tag in the explanation of thermal expansion and servo is unclear to what it refers, there being citations for both thermal expansion and servo, the subject of the paragraph. Please explain. Jobst 03:07, 26 February 2007 (UTC)
I tagged a bit of OR that seems to run counter to sources that can be located so it clearly needs a source. Also, Jobst, when someone makes a change please respect it. We work together here. When you work on the article off-line and then paste it back in you have to be extra careful to include the work of others. --Justanother 03:26, 25 February 2007 (UTC)
I was referring to text that I wrote, not text in other sections of the Brake fade piece. However, I find the two paragraphs before "Fade in drum brakes" misleading and in need of rewrite. When I did that originally, it lead to this bruhaha. The piece overlooked the basic weakness of internally expandig shoe drum brakes, which is at the core of what is commonly known as brake fade, or drum brake failure from loss of servo effect.
That makes the rest of the article a bit confusing, because it relies on the unsubstantiated drum expansion and gas bearing hypotheses. Unfortunately this idea has been repeated so often that it passes without challenge or technical explanation and need not be further substantiated. There is no scientific explanation for these scenarios.
I am aparently not able to rewrite those parts without the rewrite being erased and the original resinstated. In the discussion that ensued I was informed that it didn't matterr who is right or wrong, but that the procedures be followed. I'm open to suggestions.Jobst 06:32, 25 February 2007 (UTC)
By the way, who runs the clock on these datelines? It is 24 FEB 07 here.Jobst 06:32, 25 February 2007 (UTC)
I notice that under "history:" you feel that verification is needed to prove disk brakes operate when glowing temperatures. At the moment I cannot find a picture or technical item to cite but many pictures have been in the press showing red hot brake disks on cars to adequately to prove that it occurs without brake failure. If you were to ask readers if they have seen pictures of glowing disks, I think most would say they have. Still looking. Jobst 21:49, 25 February 2007 (UTC)
As I said, what parts of self servo is not sourced? What I find more important is the concept of drum expansion and gas bearing not held to the standards you demand. I demostrated the temperature falacy with reference to expansion coefficients and explained with citation why drum brake servo is the culprit. Jobst 03:00, 26 February 2007 (UTC)
And so is thisThis ignored how little expansion drum heating causes, (about 0.024 inch for a 400°F change) far less than normal drum deformation caused by brake shoe pressure.
You seem to be wanting to debunk myths there and you are not provinding sources. I am saying please incorporate the Bendix data on drum expansion leading to fade and please take a look at the sources I provided already and see what they say about gas cushion, gasified material deposition, glazing, binder melt. All issues that you do not address but that are covered in the sources I provided. I think that you just want to write this off the top of your head and without sources and that is not what we do here.--Justanother 03:12, 26 February 2007 (UTC)they are physically impossible, considering the volume of gas required to generate a gas bearing.
Drum brakes do not operate at the temperature you chose to calculate and cars have roughly ten inch diameter brakes. You'll note, my example took 400°F rise, your example nearly doubled that and doubled the brake diameter. The thermal expansion coefficient is 12ppm/°K. So let's get to the basics. If you believe in the expansion and gas scenario, you should give reasons for readers to believe it and give a reference that explains iut, not just repeat what common belief is. That servo is cause of drum brake failure can be deduced from what the article originally stated, that the friction coefficient decreases with temperature increase and that there is a self servo effect. You'll need to be more specific which source material you don't like. I don't know what you find amiss with my references. Jobst 04:31, 26 February 2007 (UTC)
These are air brakes on trucks that most often lock-up leaving long dual skid marks that we see on highways because they have servo action. That drums as large as these, greater than twice the diameter of passenger car brakes, which are the ones of interest, when "maladjusted" can lose contact, does not contradict that the servo action of drum brakes is the primary cause of brake failure at high temperatures. The "maladjusted" is a major caveat in that sentence. Truck brakes in question use pneumatic diaphragms with pushrods to rotate mechanical cams that spread brake shoes against their drums and are in that way different from hudraulic car brakes. Please stop creating spurious diversions. The claim of gas bearing and brake shoes not making contact on car brakes is unsupported. Jobst 05:41, 3 March 2007 (UTC)
Jobst. My patience is wearing thin. You cannot edit on a word processor and then paste back in and delete all my contributions in the process. That is extremely RUDE! --Justanother 21:57, 26 February 2007 (UTC)
I hve submitted this dispute to WP:RfC and hope to find a way of resolving the two versions on the origins of brake failure through fade in this article. As I see it, servo effect of drum brakes is the culprit, the reason why they are no longer used in passenger cars and especially racing cars. The loss of drum contact and gass bearing hypothesis should not be validated by Wikipedia.Jobst 02:47, 1 March 2007 (UTC)
I stumbled across this thread by accident: I was chief engineer of Guaranteed Brake Parts Company, in business from 1947 to 1996; originally in north Philly, and from November 1963, Camden, NJ. Among other things, we had the largest bonding oven in the world in the Camden plant; and in in the early 1950's my Grandfather and B.F. Goodrich engineer Leon Fiedler perfected the brake lining bonding process, with the phenolic A602-B thermoset adhesive. Also, our family was heavily involved with the APRA Brake Institute, with my father (Joseph Schwartz) holding the presidency of that body in 1990-1992. As a major rebuilding operation with, at the peak, producing almost a half-million disc pads and 240,000 new and rebuilt brake shoes, we had the choice of various friction material manufacturers, such as Brassbestos, Bendix, Carlisle (truck only), Certified/Lear-Siegler, Krasne, and Nuturn (Turner & Newell/Ferodo) under the Grizzly brand.
There are several causes to brake fade; but at this moment I need to clarify a common misconception about the Friction Material Standards Institute (FMSI) friction coefficient lettering. The codes consist of 2 letters, indicating the cold and hot friction coefficients, usually FF or FE. The misconception centers around the belief that the higher the friction letter (say, FG), the better the quality of the product. Not so: The piece of rubber used on a bicycle rim clamp brake is very high; but if it were attached to a disc pad it would burn right out!
Instead, what we want is a constant friction-vs-temp curve that does not have a sharp drop-off: If the curve is too steep either upwards or downwards, the result is often "grabbing" at high or (usually) low temperatures.
Keep in mind that the temperatures can get quite hot in a braking assembly, as the brake is no more than an energy dump. One of the best illustrations of this is during NASCAR broadcasts from Martinsville, where you see the cast iron rotors glowing so red hot (my estimate from the color is as high as 1100°F) it can actually damage the bead of the tire!
When the brakes get very hot, with conventional phenolic resin & asbestos or Kevlar in the area of 600°F one reaches the "kneepoint" of the curve, where the phenolic resin binder actually starts to break down. By the time the material reaches 850°F the resins "go exothermic," i.e. they catch fire! This is the principle involved with debonding furnaces, where once the lining catches fire, the resins in the lining decompose as does the adhesive. In fact, in our Bayco debonder furnace, which holds up to 4,000 shoes(!), the two main one million BTU gas burners shut down at 850°F and the water sprays kick on, to keep the load temperature under control to avoid warping the steel cores. One time during installation testing of the Bayco furnace in 1988, we let a load of 4515 & 4311 truck shoes get to 1100°F to see where the non-asbestos riveted linings would completely disintegrate, turning into powder.
OK, so we've established that brake fade on drum brakes and asbestos disc pads starts from the surface decomposition of the friction material starting at about 600°F. BUT! That is only one mode of brake fade!
Another cause of brake fade started to rear its' ugly head with the advent of metallic disc brake linings: Boiling of the brake fluid. Up until the 1970's, plain old DOT 3 brake fluid was fine for 4-wheel drum brakes, as the friction material would reach the temperature-friction kneepoint long before the brake fluid would boil. However, metallic disc pads were no longer an effective thermal insulator, instead conducting the heat through the pad, through the backing plate... And right on to the cast iron or aluminum caliper and (especially) steel piston(s), boiling the brake fluid. This led to high temperature DOT 4 and silicone-based DOT5 brake fluids, to handle the higher temps yet not boil.
[Alas, DOT5 brake fluids have a tendency to foam when used in anti-lock brake systems from all the "churning," causing fade at operating temperatures... But that's the subject of a whole `nuther discussion!]
We once diagnosed an interesting cause of brake smell (and attendant brake fade) in FoMoCo E/F-350 delivery vans in NYC: Brake balance! Turns out that the proportional valve was set to the factory specs, which put over 70% of the braking force on the front axle when the vehicle was empty. Problem was, when the trucks were (over)loaded, the rear brakes were (all but) tagging along while the front brakes were handling all the load. We solved the smell & fade problem by using a lower friction front pad and a very aggressive rear brake lining originally used in truck brake blocks.
(More to follow in a day or two, after I dig my engineering notebooks out of my parents' basement and dust them off...)
<not a good idea for here> Discpad 03:41, 14 March 2007 (UTC)
After writing up my comments and looking the article over, it is so screwed up with urban legends, half-truths, and other dubious information (including using a "journalist's" article as a primary technical source), I recommend a complete rewrite from scratch. <personal info not good idea> Dan Schwartz, Cherry Hill, New Jersey; Expresso@Snip.Net Discpad 04:44, 14 March 2007 (UTC) (By the way, as pioneers, our family is well known in the brake shoe and disc pad manufacturing industry)
Discpad -- It sounds like you have a lot of good information. Wikipedia requires that any factual claims be supported by a citation to a published work of some kind and furthermore, that original UNpublished research will be deleted immediately. Web sources are preferable, but ANY publication (such as paper journal publications) are acceptable, provide a complete citation is made. See WP:CITE for how to do this properly. IzaakB(my Talk)contribs 15:55, 15 March 2007 (UTC)
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Wow, not sure I want to stick my oar in here, but I have trouble imagining how this works; brake material wears down y very small amounts, or you'd have to replace pads constantly. Perhaps this rate accelerated greatly under very high temps, but even then I have trouble seeing how it could wear down enough for a drum brake to loose braking effectiveness. If a drum brake is self-assisting, why should the tiny fraction of an inch that wears off effect it? Wouldn't it just continue to pull itself tight against the drum? If I am pushing on a wooden block against a grinder as it wears down, the force doesn't change as the block wears down. I might move slightly closer to the grinder surface, but only a tiny bit. And with a brake system, my pedal might sink further to the floor, but not by a whole lot. Aren't brakes self-adjusting? Otherwise as they wear down you'd have to constantly fiddle with them to keep them from going to the floor every time 1/100th of an inch is worn off. If you let off the brakes, and re-apply, doesn't this serve the same purpose? I just don't see how wearing anything off a pad (or shoe, rather) is going to cause the self-servo effect to be lost...just push down a little harder, and as soon as the shoe presses the drum again, you're back in business. To return to the grinder analogy, say there is a 3-4in gap between the table and the grinder, and a block of wood is pulled into that gap, being pressed against the grinder surface. Simply wearing out the surface of the block isn't going to make it stop jamming against the grinder, it will progressively be pulled down and into the surface until the size is so small it falls through the gap entirely. Also not sure where anyone got the idea brake fade doesn't happen on disc brakes. I've driven cars with stock discs hard, and eventually they start to loose braking effectiveness. Maybe it's not as severe as with drum brakes, but it's not an extinct issue. If a person is familiar with brakes, I don't know why they'd say it was. 06:10, 29 December 2017 (UTC) — Preceding unsigned comment added by AnnaGoFast (talk • contribs)
I don't know how this section works. I just wanted to question about the "brake fade" part on the article, because it is written "The self-assist mechanism affects the water pump and the amount of fade. ". I'm French so I may don't get the meaning, but I am almost sure that "the water pump" (which ?) has nothing related to the subject. I first tryed to modify the article, but my modification was undo quickly, contributor advicing me to deal with it there. That's why I wrote that. Thank you for you help. — Preceding unsigned comment added by 78.207.139.152 (talk) 22:21, 18 September 2018 (UTC)