Does this estimate for brake work sound reasonable?

February 3, 2018 8:52 AM

Today when I had my 2014 Kia Rio LX serviced, the mechanic told me that my rear brakes were at 3 mm and that I should replace the brake pads and rotors for $375. I asked if I could wait until the next oil change, and he said it would be OK because it was the rear brakes, but that I should definitely plan to replace them next time. The front brakes are at 8 mm. My questions are: 1) Is it normal to replace both the pads and the rotors, or just the pads? 2) Is $375 a reasonable amount? 3) Am I risking a more expensive repair by waiting for the next oil change, or should I take care of this sooner?
posted by JDHarper to Travel & Transportation (13 answers total)

It’s not common to replace the rotors; they should last through four or five brake pad changes, unless something has gone really wrong, or they are defective.

Probably worth getting a second opinion.
posted by notyou at 8:58 AM on February 3, 2018

Did he mention why he thought the rotors should be replaced? 3mm on the rear pads is definitely in replaceable range, but I'm unclear why you'd also need to do the rotors too, as they generally last a lot longer than 4 years.

Also, is this the first pad replacement? If so, I wonder why the rears have worn so much faster than the fronts...
posted by saladin at 9:06 AM on February 3, 2018

That sounds cheap to replace pads *and* rotors. Are you sure the mechanic said replace the rotors? Doing a *resurface* on the rotors during a brake job is a common thing.
posted by JoeZydeco at 9:34 AM on February 3, 2018 [2 favorites]

Data point: I just had both rear pads and rotors replaced on my 2014/32K miles Subaru for $250 in Seattle, WA. I'm pretty sure the repair was completely unnecessary but I made the mistake of not asking to see the "rusty, broken part" before I authorized the work.
posted by halogen at 9:38 AM on February 3, 2018

I tend to always replace pads and rotors simultaneously. In the rust belt (are you?) the rotors often end up with rust blister ridges near the inner and outer edges which can interfere with proper seating of new pads. Many newer cars do not have extra metal thickness built in to the rotors to allow turning/resurfacing the rotors, and if the rotors are rusty they can damage the brake lathe, so machinist will refuse to turn more than lightly rusted rotors. Rotors for many common vehicles cost around $35 ea (don't expect a mechanic to sell them this cheap) so why spend the extra labor doing "field resurfacing" to wind up with a half-assed brake job? Rotors which have been turned down are more likely to warp, more likely to cause noisy brake problems and at today's labor prices, the price spread between chucking and replacing vs. extra labor to resurface is a no brainer.
posted by Larry David Syndrome at 9:48 AM on February 3, 2018 [3 favorites]

The price is Ok but get a second opinion on the rotors for sure. I got ripped off in this exact scenario by an unscrupulous mechanic when I was ~23.
posted by something something at 9:49 AM on February 3, 2018

The only reason to pre-emptively replace your pads is if, by doing so, you can avoid having to replace the rotors. If they're going to replace them anyway (which seems to be becoming standard practice), there's no reason not to put it off.

$400 sounds like a fair price for the work, at lease where I live. Also, what Larry David Syndrome says.
posted by mr vino at 10:26 AM on February 3, 2018 [2 favorites]

Response by poster: Definitely said to replace the rotor. He was telling me basically what Larry David Syndrome said, that resurfaced rotors tend to come back to the shop in six months warped.
posted by JDHarper at 10:42 AM on February 3, 2018 [1 favorite]

For the work suggested, the price seems pretty reasonable to me. Especially if those are dealer prices. It's entirely possible that new car discs do not have enough material on them to allow resurfacing - especially rears.

Just for reference - brake discs do not actually warp, that's incorrect terminology/erroneous. They do not physically buckle or warp out of true. What does happen, however, is that as the brake discs get thinner, they are less able to manage localised heat dissipation from the pad contact area and in extreme cases will allow 'smearing' of pad material onto a small part of the disc face. So, for instance, at the very end of a long sustained stop with the brakes at high temp, you may get pad transfer during the last second or so of the stop. This is often known as 'glazing the discs', and if it happens all around the surface you just lose braking efficiency. If it happens for only a section of the disc then you get the vibration effect.

The 'juddering' you feel in the pedal that people assume is a disc that has warped is actually the vibration caused by the difference in friction between the change between brake disc surface then (brake disc+pad material smear section) then brake disc again. The resurfacing of the disc is intended to remove all traces of the old pad material and machine down to a clean and new surface. However, as this reduces disc thickness it makes the machined discs proportionally more likely to allow pad material transfer to happen again.
posted by Brockles at 10:58 AM on February 3, 2018 [5 favorites]

Best answer: Replacing the pads and rotors as a set is a thing because the labor cost is mostly to remove the wheel and caliper, and it bumps up the mechanics pay by a smidge. The rotors are about $40 here

The wear limits are given in the technical manual here and are ~20mm for the rotors and 2mm for the pads. It does not require the pads and rotors to be replaced as a set.

So,
1. Yes it is normal, but not required
2. Price seems Ok
3. You are not risking a more expensive repair. You can continue to drive until you hit the 20mm/2mm values

Next time try asking the mechanic what the wear limits and service intervals are. That will signal the mechanic that you know what you are doing, give you confidence to decide to repair/delay as necessary.

Also, it helps to skim the technical manual, not because you need to memorize the contents, but it gives you some idea of what the mechanic is going to do. Check your mileage, look at the next set of required inspections and take a look at the wear items. If a mechanic comes to you with a list of items not in the wear items you can gently push back with "What is the wear limit?" and "What is the service interval?".
posted by pdoege at 12:20 PM on February 3, 2018 [1 favorite]

Many shops in urban areas don't resurface ("turn") rotors anymore. Chinese brake rotors are so cheap, and US labor is so expensive, that it doesn't make sense. You just toss them and put on a new set, unless the rotors are particularly expensive. And lots of performance cars with expensive rotors have drilled/slotted rotors, which can't be resurfaced. (Though, since nobody resurfaces anymore, you might as well get drilled/slotted ones, since they are less likely to warp.)

I sort of hate this because it seems like a terrible waste, but when you look at the price of cheap imported rotors it's difficult to argue with the economics.

In rural areas where labor rates are lower you might still find people resurfacing rotors, and lots of garages still have the machinery to do it, but I've repeatedly been told (and had people who work in the industry confirm) that it would cost more to have rotors resurfaced than replaced.
posted by Kadin2048 at 3:17 PM on February 3, 2018 [1 favorite]

Also questioning why the rotor replacement or resurfacing. If the pads haven't worn past the wear limits where the backing or fasteners damage the rotor, I'd slap in a new set of pads and drive on.
When I was younger and poorer, even if there were grooves cut in the rotors by completely gone pads, I'd just throw in some new pads, which would wear to conform to the grooves in pretty short order.
My previous vehicle, a 2000 F150, went through I think three or four sets of front pads and one set of rear pads. I never replaced the rotors.
posted by rudd135 at 4:18 PM on February 3, 2018

My guess (being as the discussion already mentioned resurfacing with the garage, based on the update) that there is signs of pad material transfer, or the discs show at or more than 50% wear. So resurfacing won't help, even if the discs are not actually worn out now. So it makes sense - being as replacing the pads does almost the whole job in terms of labour anyway - just to throw a set of discs on if they are cheap, which the quote absolutely supports. Unless a resurfaced par of discs would last the life of the replacement pads (unlikely) then it's not cost effective to replace just pads now.

I suspect a Ford F150 has much, much more heavy duty brakes on it than a 2014 Kia. At least, I'd certainly hope so.
posted by Brockles at 4:50 PM on February 3, 2018 [1 favorite]