Scraping noise a telltale sign that brakes need attention
My truck has begun to make a whistling noise which is now becoming a light scraping noise from underneath. I hear it at low speeds especially when the windows are down or I’m next to a guard rail or wall. The odd thing is it changes or goes away when I press on the brakes or turn sharply. What is causing this? — Zach P.
It sounds like one of your front brake pad sensors is beginning to rub on the brake rotor. These are small metal tabs attached to the pad backing plate that warn you that your brake pad thickness is down to perhaps 20 percent remaining. One would think a brake sensor would sound off when you apply the brakes as opposed to when you’re not! I believe this is due to flexing of the brake pad when applied, and since turning changes the noise, it’s likely a front pad. The noise will worsen to a continual or in many cases an oscillating shrill squeal that will make the truck embarrassing to drive!
An on-vehicle brake rotor machining process is a good idea when renewing pads, to restore the rotor surface to optimum condition. And you get what you pay for with brake pads. Don’t go lower than the upperthird of the price range choices!
Vehicles still using drum brakes in the rear will not have a wear sensor there. It’s prudent to sneak the drums off for a quick peek during each tire rotation in order to avoid a surprise metal-on-metal condition which ruins the drums.
You’ve mentioned previously of driving an electric car. What do you think are the main attributes that offset the high cost and inconvenience? — Ken B.
There are several that resonate with me. First, the quiet rush of torque from stoplight to stoplight, or exiting a turn on an uphill mountain road with a straightaway ahead. Electric cars have amazing low-end grunt, which is the driving situation when most people really appreciate it. Next is regeneration. I live atop a mountain. I try to curtail overnight charging early in order to allow room to top-off the battery when descending the mountain. I smell overheated brakes from the other cars (not using gears as they should) and look down to see my battery filling, enough so to provide perhaps ten additional miles of driving that would have been otherwise wasted as heat. Selecting the low (maximum regen) mode also makes it almost a one-pedal car as there is considerable slowing as I ease up on the throttle. Another is maintenance, which is minimal at most, and the brakes last practically forever. And the fuel cost savings compared to my conventional car gathering dust in the driveway makes the lease payment. And finally, the lack of moving parts, friction, pressure and other issues that are non-existent when sitting at a red light!
The one huge negative is the battery. Super expensive and it won’t last forever.