Warped rotors at 60k on a Subaru Forester

subaru
brakes
forester

#1

I recently took my '07 Forester (60k miles) to get my brakes done at a local (and trusted) mechanic. He discovered that my rotors were warped and recommended replacement (he believes machining them is a ripoff due to labor costs and rotor thinning). This is the first brake job I’ve had done on the car and it seemed odd that I would have to replacement the rotors. On replacement, he found that the brakes were running hot and suspected this was due to a hillstop mechanism (it’s a manual transmission, so this mechanism engages the brake when you idle on a hill to prevent the car from “rolling backwards” before you accelerate). He managed to adjust the hillstop mechanism to reduce the problem, but he said I will likely have to get the rotors replaced in another 60-70k, regardless. He also said that he’s seen things like this before with Subaru’s. My questions are: Is this normal? Isn’t it excessive to replace rotors every 60k miles? Could there be another reason for the brakes running hot?


#2

Rather than “hot” brakes warping your rotors, it is also possible that whoever rotated and/or replaced your tires overtightened the lug nuts.

The impact guns that are favored by many mechanics will result in lug nuts that are overtorqued, and that has ruined many a brake rotor. Your lug nuts call for 72 ft lbs of torque, if I recall correctly, so it is very possible to overtorque them and warp the brake rotors.


#3

Please define “brakes running hot.” Brakes get hot when they are used. This is how they stop the car. The friction between the brake pads and rotors generates heat (quite a bit of it) as the vehicles is slowed and stopped. This heat is dissipated through the rotors and calipers.

If the brakes on your Forester were dragging for some reason they might be getting too hot, but you didn’t say they were dragging.


#4

60k on rotors is nothing unusual, but I’m puzzled - did you notice anything unusual (pulsing pedal, vibration, etc) before you took them in? It’s odd to have warped rotors with no symptoms.


#5

You can have your rotors machined only once. After that, they need to be replaced. I do my own brake work and replace the rotors every time I change pads. It’s the least expensive way to do it at home, and may be almost as inexpensive as machining them at the shop.


#6

If you never felt pedal pulsation or any other vibration when braking at highway speed then I question the credibility/competence of this mechanic.


#7

What if the mechanic found the rotor had runout but not enough that the operator could feel it in the pedal? At 60k, there has been wear and we know rotors are manufactured with the bare minimum thickness these days. How do you think the OP would feel if the mechanic did nothing and 3 months down the road the rotors warped enough to be felt in the pedal? Imagine having to redo the entire job, including new pads because of a misguided attempt to eek every last bit of life out of the rotors. Penny wise and pound foolish IMO.

Personally, if I ever had to rely on someone else to do my brakes, I would expect and appreciate fixing it right the first time rather than pinching pennies and having the inconvenience of a return trip at added expense. Just something to consider before condemning the mechanic…


#8

Replacing rotors at 60,000 miles is not unusual. Two of my last three cars have needed them replaced before then, although I’ll admit I may be a little harder on the brakes than the average person.

Replacing them instead of turning them is pretty common. These days, rotors are made without a lot of extra thickness. At most, you can turn them once, but then they’re right at the limit and they’ll warp again more easily. It’s simpler just to replace them from the start.