Anyone else ever run into a problem where their rear brake pads wore
out at 14K miles? I mean all four worn all the way down. This is not
an issue with one side of a caliper hanging, nor did the dealer find
anything wrong with the calipers.
It's my wife's car and she does do a lot of city driving but the front
pads have hardly been used (10/32" remaining, new pads measure between
11&12/32") and the rear ones are shot. The dealer I took it too turned
the rotors (under warranty) and replaced the pads (at my expense of
course) and said they didn't see anything mechanically wrong and to
bring it back in another 3-4K for them to take a look at it.
Looking for any info I can relay to the dealer to tell them to look for
if anyone has come across this problem. Any help would be appreciated.
Well, that's not the case in this situation. And it's my understanding
(though I may be wrong) that the parking brake only enages the rear
driver's side brake. Therefore, this would not explain the same wear
on the passenger's side. My intial thought was that maybe the parking
brake wasn't releasing completely, but if my assumption is correct
about the parking brake only engaging one set of brakes, that
eliminates that as a possiblity as well.
Don't be so sure. I just checked the online service manual on Hyundai
Webtech and the parking brake definitely works on BOTH rear wheels. For
that matter, I've never heard of a car that only used one wheel.
Remember, in addition to it's parking duties, this is the emergency
brake that you're supposed to use in case of a hydraulic failure in the
main brake system.
I'm not familiar with the Elantra, but does it actuate the normal
service brakes for the parking brake function? I'm pretty sure the new
Sonata has separate drum brakes for the parking brake separate from the
disc service brakes.
That appears to be the case. The diagram isn't as clear as I'd like, but
it looks like it actuates pads that run inside the periphery of the
cylindrical part of the brake disk. If that's actually the case, it may
be fine for parking, I can't see it being of much use as an emergency brake.
Smart companies like Saab use the front brakes as parking/emergency
brakes so that you still have ~70% braking capacity in the case of a
complete hydraulic failure. They also use dual diagonal braking circuits
instead of front and rear circuits, so you don't lose more than 50%
braking capacity if one circuit fails.
This being the case, it sure sounds like the person had run the car for
a long distance with the parking brake on to wear our the rear pads well
before the fronts.
Does the Elantra and the Saab actuate the service brakes as parking
brakes using the main hydraulic system or do they use a mechanical
system that somehow actuates the main brakes?
....I remember when I was a kid and a new licensee....My older cousin was up
from Maryland with his newish Audi Fox. He let me and a buddy take it for a
joy ride. We went 20 or so sluggish miles. It smelt really bad when we
pulled into the driveway! You can guess... we went those miles with the
E-brake set. What a knucklehead I was.
Check the proportioning valve. (I assume it has one!). The function of this
valve is to reduce braking pressure on the rear brakes. That's because the
rear wheels are much easier to lock under hard braking than the front
brakes. It's possible that computer control/ABS have supplanted the
proportioning valve. I haven't been under a new car to check, thank
Meanwhile, you can jack up each rear wheel and give it a spin. They should
spin freely, or perhaps with a slight intermittent light rub. (Even
near-perfect rotors usually have .0005-.001 runout, and can rub a little bit
in spots.) If the pads rub hard enough to prevent a full spin or 2, you
have a problem.
It has the original shoes and drums because they are not doing anything.
You can expect to get a million miles out of these. But that does not make
them a good brake system. Drum brakes are essentially useless after <10,000
miles if you don't keep them adjusted up. Don't count on the automatic
adjusters to do that for you either. But - if you prefer lots of miles to
real braking, then by all means - love them drum brakes.
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