2005 BMW 325i Rotor Question


#1

In late 2007, I purchased a 2005 BMW325i. In Dec.2008, I had new front and rear brakes put on. In June 2011, I had new front and rear brakes & rotors put on from a recommended mechanic/garage . Fast forward to now, I felt a little vibration in the steering wheel when going ~50mph+ and applying the brakes. I took it to the same mechanic from 2011 and was told that my front rotors were warped. I had them replaced and now feel a slight vibration on the brake pedal when I’m traveling fast and press down on the brakes. (The vibration could have been there prior to the new rotors as I was focused on the steering wheel).

My question–> Should rotors last more than 2 1/2 years, especially when I didn’t need to replace them from 2007 - 2011? I do the same driving and put on ~10k miles per year. Also, since I got new front rotors, why is there a vibration on the brake pedal? Does this mean that I need rear rotors?

Appreciate your insight!


#2
Also, since I got new front rotors, why is there a vibration on the brake pedal? -

Sure that’s not your ABS system kicking in??


#3

One frequent cause of warped rotors is incorrect torquing of lug nuts. Had tire rotations done since the new brakes? Maybe they were improperly done in the first place, but it is extremely difficult to prove any liability.


#4

Has anyone checked your front suspension?


#5

What kind of driving do you do? That’s an awful lot of brake work. You may wish to investigate some high performance pads and rotors.


#6

Rotors warp

It’s a fact of life

With my previous car, I always torqued the lug nuts. Yet, after several years, the rotors warped

In any case anybody’s curious, when they warped, they were still 1.5mm ABOVE discard thickness


#7

According to what I read on a brake pad manufacturer’s website, sometimes what feels like warped rotors is actually a bad spot in the rotor caused by stopping with really hot brakes such that some brake pad material transferred to the rotor and bonded with the hot metal. If that may have occurred, then I would expect that it happened to all four rotors, and as you say, the vibrating steering wheel distracted you from the sensation in the brake pedal.

If that is the case, and you can stand it, I would say just drive it that way. It will take a very long time before the problem goes away and it may never go away because the brake rotors won’t wear evenly once they have that spot in them and they will always be uneven until they are eventually replaced.

When rotors warp because of uneven torque on the nuts, it has to do with uneven heat transfer from the rotor to the wheel and the hub. Heat transfers better at the tighter lug nut. After a few hundred of these asymmetric heating and cooling cycles, the rotor can warp.


#8

P.S. On a BMW, if you use BMW branded rotors and pads, it is not unusual to need to replace the rotors every time you replace the pads. BMW front brakes typically last from 40 to 80k miles, depending on driving pattern. Rear brakes last a bit longer than fronts.


#9

Let me suggest you try this:
jack up each wheel individually and have a friend slowly apply the brakes while you spin the wheel by hand. If you have a warped disc, or glaze on a a disc, you’ll feel the uneven friction on the wheel as you spin it. Once you know exactly which wheel it is, you can look at it from there.

2-1/2 years is not unacceptable for aftermarket rotors. Or pads. Depending on how you drive (and where), that might be perfectly good. I’ve seen rotors badly rotted after only a few months parked in a wet area beneath trees, and even seen rotors develop surface rust while I was shopping in the mall on a rainy day. Lots of these things can affect brake life.

There’s also the possibility that the source of the vibration is other than the brakes, and has become noticeable over the last 2-1/2 years. Have you checked your tires for irregular wear? Did you have the wheels rotated when you had the brakes done 2-1/2 years ago? Did you have an alignment done?


#10

Try a couple hard stops from 60 mph, not to lockup but pretty hard none the less. Don’t quite come to a complete stop, just short of it and then release the brakes and start rolling again. This should burn off any build up of resins on the rotors.

If you had new pads installed with the rotors, there might be a quick build of of resins if you did not do any hard breaking. If you did not get new pads, it is possible the shop did not completely clean the rotors before installing them leading to other contamination of the rotor surface.

Anyway, the cost to do this test is essentially $0.00 as long as you do it safely.


#11

It depends on driving style, but needing to replace rotors every 2 1/2 years isn’t that unusual I expect. Esp on performance cars. Is rotor replacement an expensive thing on BMW’s? When I’ve had to do it (on my old VW Rabbit) it wasn’t very expensive. Compared to other repairs anyway.