XPost: comp.mobile.android, misc.phone.mobile.iphone   
   From: spam@nospam.com   
      
   Xeno wrote:   
      
   > Yeah, that's been the trend for quite some time now. Rotors are   
   > considered as *disposable* as the pads themselves.   
      
   Hi Xeno,   
   (See the question in the bottom of the introductory explanation below.)   
      
   A _lot_ of morons (like Steve) "claim" to need to replace rotors with every   
   pad change, and even more morons opine that they simply replace rotors at   
   every second pad change, and even more morons than those prevalent types,   
   ask on the car forums the dumbest question possible, which is   
    Q: *How do you know when to replace your rotors?*   
      
   The reason all those three are the brain child of morons is that you   
   replace a rotor when it no longer meets the spec, and, as you note below,   
   the spec contains a few simple components, _all_ of which require tools.   
      
   Just as Dunning & Kruger wondered what made the bank robber think the lemon   
   juice would work, and just as I wonder what makes iKooks believe their   
   fabrications of functionality would work, I have wondered for years why   
   people ask the dumbest "what oil" type of questions on car forums.   
      
   Over the decades, I've realized the "what oil" questions and the when do I   
   replace rotors questions are born of the exact same "Steve" mentality.   
   1. They don't know the spec, and,   
   2. They don't own the tools to _measure_ to the spec.   
      
   It's really that simple, don't you think?   
    Q: When do you replace rotors?   
    A: When they no longer meet the spec.   
      
    Q: On rotors, how do you know when they no longer meet the spec?   
    A: You measure them.   
      
    Q: What tools do you need to measure rotors?   
    A: The most often missing tool is a dial gauge with a good sturdy mount.   
       The second most often missing tool is a simple one-inch mic.   
       The third most often missing tool is a gouge depth and width gauge.   
      
   The tool I don't yet own is the latter (as I've never needed it).   
   So I use a coin of the correct width but that's not the "right" tool.   
      
    Q: What tool do _you_ use to measure the depth and width of a gouge?   
    A: Xeno?   
      
   >> There is one train of thought that turning sufficiently thick, flat,   
   >> non-warped, rotors, is unnecessary and that after a short while the pads   
   >> will break in to match the minor imperfections in the rotor, with just a   
   >> little extra wear on the pads. "If your rotor surface is smooth there is   
      
   > Indeed, I need to see a very overt issue before I would bother machining   
   > rotors. If you don't feel the symptoms on a road test, measurements look   
   > ok and the surfaces aren't gouged, I just fit pads, then do a bed in process   
      
   Given rotors cost about what it costs to machine them (and, in my last   
   clutch replacement, flywheel machining was $60 while a brand new flywheel   
   was only about $80), I have never bothered to have _my_ rotors machined.   
      
   However, I've also never taken a car to a mechanic in my life for something   
   as trivial as a four wheel brake job, which is just about the easiest job   
   anyone can do at home if they have the most basic of the simplest of tools.   
      
   The bed in process is critical in terms of what people call 'warp' (which   
   is simply that the car does funny things, which I won't call 'shudder' or   
   'judder' or 'shimmy' or 'pulsations' since people call _everything_ "warp".   
      
   However, that bed in process takes an appreciable amount of time,   
   especially in areas like those where I live where the highway is nowhere   
   near, and it's jam packed during all hours of the day with traffic.   
      
   My question to you, Xeno, and to any others who get brakes done by the   
   professional mechanics, is this simple but very important question:   
      
    Q: Do professional mechanics take the car on a drive to do proper bedding?   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)