Talk:Brake fade

message: "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."
"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."
:OK, what about drum brake fade?! Dan Schwartz, Discpad 04:05, 14 March 2007 (UTC)
replies: text: Jobst, your change in approach is noted and appreciated. Thanks. If I may make a suggestion, would you please rewrite this section, Fade in drum brakes, completely to conform with the Bendix source and other sources as appropriate. Make your changes in the article itself. Regarding disk brakes, I would appreciate it if you did not change anything there until we discuss it and I will not be able to do any more here until about 8 hours from now. --Justanother 19:08, 21 February 2007 (UTC)
replies: text: I just copied the section below for convenient reference. I would like you to rewrite that part in the actual article, not here. Let's leave the other sections of the article for later, please. --Justanother 20:17, 21 February 2007 (UTC)
thread_title:  Bendix sources and other sources to improve the article 

message: 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)
thread_title: Quick note

message: This vote is to decide if we should keep the  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
#Oppose I don't think it is necessary. Johann...[ T...C ]  01:44, 24 February 2007 (UTC)
replies: text: That is patently false: Rear drum brakes are still used extensively on light trucks and SUV's; and almost exclusively on heavy trucks. Dan Schwartz Discpad 03:53, 14 March 2007 (UTC)

text: Jobst, this was put here by someone else to show you how you might go about reaching consensus on a disputed issue. This one was if the  tags that I think you put should remain. It is kind of moot now as they are gone anyway and no-one wanted them to remain; the new  tag I put should stay for a while. The way it really works is if no source is provided after a wait then the info goes not the tag. Thanks --Justanother 23:07, 25 February 2007 (UTC)
thread_title:  Vote 

message: 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)
replies: text: Working my way upwards (since it's late at night), the cause of drum brake fade is NOT the loss of servo effect: If this were true, then fixed anchor drum brakes (such as the FMSI part# 501 on the Ford Tempo or 583 on the Taurus/Sable) would not suffer from fade; nor would heavy trucks using the 4311 (Eaton), 4515T (Timken) or 4515F (Fruehauf) cam brake assemblies, nor the 4602 wedge brake assembly, also all with fixed anchors. Instead, it is caused by the friction coefficient curve (friction vs temp curve) reaching the kneepoint where phenolic resin breakdown starts to occur. Please see my entry below. Dan Schwartz Discpad 03:56, 14 March 2007 (UTC)

text: You must be on the West Coast. The time is UTC, the same as Greenwich Mean GMT? One of the refs I saw and I think I put a link puts the gas thing as a deposition and redeposition issue rather than a cushion of gas. Also the melting of binders is a factor. And the green fade thing. The expansion of drums should be mentioned, I think, as Bendix says it is an issue if the brakes are out-of-adjustment. Not all myth but perhaps over-stated in the past. --Justanother 06:39, 25 February 2007 (UTC)

text: You misunderstand me. My request applies to the paragraph as a whole, especially any "debunking of myths" that you want to do. Actually, the red-hot disk is the least of my concerns, though, of course, it should be sourced too. --Justanother 22:36, 25 February 2007 (UTC)

text: Hi. It is possible that you need to make an adjustment to your idea of how this wikipedia works. You do not demonstrate or prove anything with explanations or calculations. All proving is done by showing sources. This is NOT about writing explanations. You can write an explanation, sure, but it must be backed up by sources. This is about sourcing. Every single idea should have a source and the source should be mentioned. If not then you can put the  tag and ask for a source. But don't discount "popular media" as sources. They are allowable. To clarify. This is unsourcedThis 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.And so is thisthey are physically impossible, considering the volume of gas required to generate a gas bearing.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)
replies: text: Jobst, you cannot add links to images. All images must be imported according to WP:IMAGES. Re drum expansion. Per your link red = 1400 F = 760 C. Expansion on a 20" truck drum at that temp works out to 0.18", certainly enough to cause a problem if brakes are out-of-adjustment and that is what Bendix says. --Justanother 04:13, 26 February 2007 (UTC)
replies: text: And, Jobst, I know the learning curve here is probably like nothing else you ever experienced (it was for me too) but a "source" means a "reliable source". Please read WP:RS to get an idea. Again, the main policies are all at WP:PILLARS. --Justanother 04:13, 26 February 2007 (UTC)

text: Bendix. Trucks. "If brakes are maladjusted, and overheated drum may expand to the degree that push rod travel is insufficient to fully actuate the brakes." --Justanother 04:35, 26 February 2007 (UTC)

text: "Please stop creating spurious diversions." Amigo, please do not fight with me or disrespect me. If you cannot "play well with others" then you should not be here and should go to http://www.blogger.com where you can write all you want and not be bothered by others. --Justanother 21:15, 26 February 2007 (UTC)
thread_title:  OR in drum section 

message: 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)
replies: text: Last time I'm telling you this Jobst. If you cannot edit with another person then you have no business here and I will take necessary measures --Justanother 01:05, 27 February 2007 (UTC)
thread_title:  Jobst - please stop [[WP:DE|rudeness]] 

message: 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)
thread_title:  Submission to [[WP:RfC]] 

message: 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)
replies: text: Super. Please don't waste your expertise here in the talk page. Write in the article. I will be going on break from editing here soon. Perhaps you and Jobst can work together toward a good article. If you run into trouble or need help then just post to my talk page; I will be checking in from time to time. Later. --Justanother 03:54, 14 March 2007 (UTC)
replies: text: Whoops. Do not use strikeout or italics in the article. Do not disrespect the sourced edits of others. Merge your material into the existing article so as to explain and provide additional detail but do not remove material unless is is false and. if false, it is better to fix it than remove. Do not write above the head of the casual reader. Or if you do make sure that the layman's explanations are in place too. See WP:PILLARS. Read the policies. --Justanother 04:33, 14 March 2007 (UTC)
replies: text: The problem is that the information "cited" is patently false: It comes from a Times journalist who is proffering false, unsourced information in his newspulper article. Dan Schwartz Discpad 04:41, 14 March 2007 (UTC)
replies: text: If the cited source is bad, then cite other better sources. AlistairMcMillan 21:35, 14 March 2007 (UTC)
thread_title:  OK guys, I'll try to `splain 

message: 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)
replies: text: OK, Dan, if you want the spam then leave it here. If you want to improve the article then great. Just realize that you are not the only editor on wikipedia. I imagine you object to the gas cushion bit? Then remove it. I did see some more realistic sounding explanation about gas transport of binder material and deposition and redeposition of same on disks and pads (glazing). Anywho, write a nice bit and do not object if other editors cut it up. ps. Wikipedia is tough on experts. I know because I have my own areas of expertise (not brakes). --Justanother 04:50, 14 March 2007 (UTC)
replies: text: I already get a lot of spam, and I have a challenge-response spam blocker on my Expresso@Snip.Net public email account. In any case, the phenolic resins used in friction materials are thermoset plastics, i.e. they don't plasticize at elevated temperatures: They disintegrate. Discpad 05:00, 14 March 2007 (UTC)
replies: text: OK, I will not argue with an expert. How does "glazing" fit in then? Pads glaze, right? --Justanother 05:03, 14 March 2007 (UTC)
replies: text: "Glazing" is caused when the inorganic fillers (such as the chrysotile allotrope of asbestos) heat and literally turn to glass. But, this is not a transient (fade) effect Discpad 16:10, 14 March 2007 (UTC)

text: I've been out of the brake shoe and disc pad manufacturing industry since 1995; though I've stayed in touch. I'll have to dig down in the dusty shelves in my parents' basement for some of the Grizzly and Bendix TSB's (tech bulletins), especially on the NAO linings & pucks. The problem is that when a customer's customer (like a rental fleet at JFK, or the Atlanta PD, or AC casino limos) would have a problem, I or my father would go out and investigate (most of the time is was installer error, like not machining the rotors when switching to NAO, i.e. just doing a "hang job); but if it was serious, an engineer from the lining manufacturer would join us... Then this information would either be fed back to the manufacturer's engineering for reformulating (like pads crumbling under excessive loads: For obvious liability reasons this would be confidential inside the friction material manufacturers, with silent changes to the formulation and/or "silent recalls" where we would swap out customer stock); or technical information would be conveyed to our W/D & jobber customers, such as the E/F350 brake balance problem on overloaded city delivery vans (see above). We would call the customers who were affected; and also on occasion put a "statement stuffer" to alert all customers. Keep in mind this was all before the Web came into prevalent use (pre-1995); and this was the customary trade practice for decades. Deal with it! Dan Schwartz Discpad 13:40, 17 March 2007 (UTC)

text: Although there are lots of words under the current discusssion heading (Article all screwed up) I see no reference to servo action of drum brakes or why motorcycles and passenger cars no longer (and Railways never could) use drum brakes.  I hope those involved in editing this article can separate changes in friction coefficient, as Dan mentions, from brake failure, commonly swept under the same rug in the past.  I tried to capture that in the sub-article "Why drum brakes fade" as Justanother suggested.  I hope we can get the whole articel to agree at some time.  You can see what I initially proposed in my first edit that got bumped for the original version.  I prefer to have change in friction coefficient defined as brake fade and brake failure resulting from such chages identified as a result of drum servo action, the reason we don't use drum brakes any longer where speed control is most needed.Jobst 01:18, 18 March 2007 (UTC)
thread_title: This article is so screwed up

message: Hello fellow Wikipedians,
I have just modified  on Brake fade. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
*Added  tag to http://digital.lib.msu.edu/collections/sesquicentennial/se/se-38.pdf?CFID=1834320&CFTOKEN=86763474
*Added archive https://web.archive.org/web/20091213045044/http://www.safelinebrakes.com:80/brake-pads/brake-lining-burnishing.html to http://www.safelinebrakes.com/brake-pads/brake-lining-burnishing.html
*Added archive https://web.archive.org/web/20100607153712/http://www.fourproducts.com:80/FSBC.htm to http://www.fourproducts.com/FSBC.htm#Graph
*Added archive https://web.archive.org/web/20110711021548/http://www.fourproducts.com/Images/Development_of_the_FSBC.pdf to http://www.fourproducts.com/Images/Development_of_the_FSBC.pdf
*Added archive https://web.archive.org/web/20100607153712/http://www.fourproducts.com:80/FSBC.htm to http://www.fourproducts.com/FSBC.htm
When you have finished reviewing my changes, please set the checked parameter below to true or failed to let others know (documentation at ).
Cheers.—InternetArchiveBot (Report bug) 07:51, 7 November 2016 (UTC)
thread_title:  External links modified 

message: 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)
thread_title:  "Loss of pad material"? 

message: 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)
replies: text: I was wondering about that too.  Since water-cooled brakes are rare animals indeed and were generally a total-loss system, whether they were actually used for brake cooling (like on the Broadspeed-developed Jaguar XJ12 racers or the John Pope Special) or as easily-dumped ballast (not a few early 1980s normally-aspirated F1 cars). Mr Larrington (talk) 01:08, 29 March 2022 (UTC)
thread_title:  Request modification