I just got back my 2003 Highlander from service, and I had a question about something that was done and my mechanic’s explanation for it.
The car has 58K miles on it, and they told me I needed new brakes, so they replaced the front and rear brake pads and rotors. This ended up being very expensive, and I asked about why I needed the rotors replaced rather than machined. I was told that on some of the newer cars like my Highlander, the rotors were so thin that it just didn’t make sense to machine them - it was likely to come out unsatisfactory and they’d just have to replace them shortly.
So, is this correct? This is an independent repair shop that I’ve gone to for years, and they’ve always done right by me, although recently there have been a few instances with problems in quality, mostly not getting the job right the first time. My car IQ is nearly nonexistent (I barely know what “machine the rotors” means), but they’ve never seemed to take advantage; they’ve actually taken care of some stuff over the years without charge.
Thanks in advance.
All rotors have a minimum thickness. If machining your rotors would have taken your rotors below their minimum thickness they wouldn’t last long. It is true that many rotors are built with very little extra metal on them and so your shop probably was telling the truth. I wouldn’t lose any sleep over it.
Yes, it’s pretty common to replace them now. I tried getting mine turned, the shop messed them up, had to replace them anyway. If you trust this shop, and they’ve treated you well otherwise, I’d go with them on this.
Your not being decieved,all is well.Rear rotors (non-ventilated in particular) are very thin to start with, rotor replacement is a industry standard.
The explantion you were given is correct. Machining the rotors simply means putting them on a brake lathe and a carbide bit is used to true the rotor surfaces by cutting the rotor surfaces perfectly flat.
Another side to this is cost. If a shop has a shop rate of 70 dollars a flat rate hour for example the labor guide book may quote an hour of labor to machine one rotor. This does NOT include labor for removing and replacing it.
This means you would get hit for 70 dollars just to machine that one rotor and that’s assuming the rotor was not warped so bad that machining would be a waste of time.
Often new rotors can be purchased for less than the flat rate labor required to machine them plus with a new rotor you would have one with a full thickness.
Hope that explains it.
In an effort to improve ride and reduce cost, most modern cars are designed with light weight rotors. The new rotors cost a little less than the old heavier designs, and they mean less labor cost when doing a brake job (less time involved in removing and replacing rotors than removing machining and replacing). That way you get new rotors every time, fewer problems and all for a few $$$ more or less. I ask that they replace my rotors every time even if they look like they could last. I like to know my brakes are in good shape.
Another reason for thinner rotors is they dissipate heat significantly better. Extremely hot or overheated rotors are not particularity effective at stopping.
More frugal mechanics(mine) will replace the pads only if rotors look okay and then test drive and see if the brake job is acceptable.