Note the little V-shaped springs across the edge of the pads. These simply insert into holes, and come right out. They're retained by the close presence of the caliper when it's installed.
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Inspection of disk brakes is something that I try to do once a year, usually
as part of general cleaning-out a winter's worth of road salt abuse.
It is well known that hybrid and electric vehicles will seriously under-use
their service brakes due to regenerative braking, so it's easy to slip into
a mindset of not worrying about pad wear much at all.
That's valid, but there are other parts that can still present issues --
notably, the slide pins that the calipers float back and forth on, as well
as the little spring clips that keep the pads in place in the caliper frame
and help keep them from rattling around.
If the parts of the caliper cannot move freely, we can run into problems
like uneven pressure on either side of the disk, or a pad dragging.
It's also good to *use* the service brake fairly frequently, even if just a little bit, to move parts over their normal range and also to scrape off any accumulated rotor rust. Rotors are bare steel, and tend to begin sprouting rust when sitting in damp weather. The usual trick to defeat regeneration and use *only* the service brakes to slow down is to put the car in Neutral, do a nice smooth braking event, and then go back into normal Drive. The energy loss relative to an entire trip is negligible, so a friction braking event here and there isn't going to anger the Hypermiling Gods. For nitty-gritty details on brake calipers in general, refer to the first part of the Prius brake disassembly. This is just a quick overview of the equivalent on the Kona, notably on the rear wheels which have the weird electric parking brake actuators. So one difference is unplugging the connectors to those, but otherwise it's pretty much the same stuff. Other than making sure the parking brake is *un*set at car power-down, there doesn't seem to be any special procedure needed to disable the braking system, as the Kona doesn't do any automated pressurization checks after power-down like the Prius did. [In the end, as long as time was given to let the Prius system go quiescent, it wasn't really needed for that either.] This page is only exploration of the rear brakes, about a year after taking ownership of the (second!) Kona. About a year after *that* I finally got into the front ones, detailed in more depth in a second page. They were definitely due for a look by then. |
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A pair of bolts attaches the caliper to the slide-pins in the frame, and it
pops off easily.
In this case, rotating the slide pins a little and pushing them in and out
reaveled by feel that they didn't need disassembly and re-lubing yet, so
they were left in place.
See the Prius page for details on those, at least for now.
Note the little V-shaped springs across the edge of the pads. These simply insert into holes, and come right out. They're retained by the close presence of the caliper when it's installed. |
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The biggest pain in the butt here is the tiny little barbs on the pad clips, which retain the pad ears in place. The easiest way to deal with releasing one seems to be pinching it down with needlenose pliers, and slipping the pad end past it. Once it's free at one end, the pad is easy to remove. |
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The inner and outer pads are clearly different, and have the anti-squeal shim plates integrally attached. |
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The V-springs seem awfully fragile and undersized. How long will a generic bit of steel wire last under the assault of winter road salt? I hope replacements are available a la carte at the Hyundai parts counter. But maybe such skepticism is misplaced? The springs in the rear drums of the Prius didn't corrode away to nothing under similar conditions, but they had some kind of magic coating on them. |
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They're supposed to push the pads apart when the brake isn't applied, but they don't do this very well. Especially when the pad-to-clip contact gets dirty, and makes the pads far more reluctant to slide. In fact, it was this exact "stuckness" that kept me hearing a slight scraping brake drag coming from the rear when starting a drive, particularly on a humid morning after the rotors had sprouted a little bit of rust. On a year-old car, the rear rotors were already getting a little scored up, possibly because of this. It was one of several motivators to get in here and have a look at things and see if there was a solution. For the moment, I think the solution is just to keep the various moving parts decently greased. Like "Carlos" enthusiastically endorses, in a comment to the above-referenced article on shims! |
_H* 220708, finalized 230526