Rotor replacement, what's normal?

I have a 2001 BMW 330xi. I drive a short distance back and forth to work but also drive about 500 highway miles rt every weekend. I’m the original owner and have never had any real issues with the car.

At 110,000 miles, the car started shaking during breaking and the rotors were replaced. The car started shaking again at 112,000 miles; the new rotors had rust, were sanded down and ok for another 2,000 miles. The rotors were warped, planed, and ok until I hit 119,000 miles. The repair guys put in new rotors and said they had no idea what was causing the problem. 3,000 miles later, the car has started shaking again. Any ideas what might be causing this?

The problem starts manifesting itself during right hand turns - there’s a slight tremor you can feel in the pedals. Then the car starts shaking, but not badly, during normal breaking. It usually becomes a full blown problem after one of the long weekend trips.

Almost certainly, it is the use of cheap after-market rotors. Get good quality after-market or get the OEM rotors.
Also, have the calipers been replaced?

Rotors should last longer than the life and miles you are getting. It seems like the calipers are not fully releasing pressure on the pads. This causes the pads to contact the rotors and wear them prematurely. The calipers need to be checked and either rebuilt or replaced. There may be other components of the brake system a fault.

If the calipers are OK then your ABS and traction control systems may be telling the brakes to apply pressure to the pads. This could mean a flush of the brake fluid and replace with new clean and proper fluid, a bad sensor in the system, or bad ABS control computer module.

I would check for frozen caliper slides and restrictions in the brake hoses first. Frozen slides can either cause the rust you described or premature warpage, sometimes both. Some hose designs feature a steel bracket to keep the hose away from moving parts, and this bracket can develop rust around the area clamping the hose. This causes a restriction which can act like a sticking caliper. Most of the time that will cause a pull (one side affected more than the other), but it is still plausible. Calipers are still a suspect, but even the cheapest rotors should last longer than that.

The wheels could be getting overtorqued when they’re reinstalled. Our local BMW dealer does that regularly.

Calipers… then a new mechanic…

Much in line with other responders I’d ask you to qualify the following from your statement “The repair guys put in new rotors”

  • Who’s repair guys ?
  • Who’s new rotors ?

If these are ‘Made in China’ Hoochie Kaboochie Mk IV Brake Rotors installed by some chain shop monkey it’s highly likely you just found your root problem cause.

Take the car to a reputable mechanic (preferably an independent BMW shop) and have the run out checked on the new rotors before you do anything else.

A BMW independent is not really needed for brake work. Any competent mechanic can choose and install quality parts. Just request them.

Despite what people think and the dealer thinks, BMW’s are nothing special when it comes to basic repair like this(even moderate).

Response to Scudder:

The repair shop I’ve been taking the car to for the last four years specializes in European cars; they’re also an authorized Bosch service center. The rotors, and all other parts they’ve replaced, are BMW approved. I haven’t been charged for any of the work they’ve done since the initial cost to replace the rotors.

One does not “sand down” rotors (whatever that means) because they “had rust”. Surely the shop did not tell you that rust was responsible for this problem?
If so, find another shop.

The shuddering is being blamed on brake rotors and there are a number of things that can mimic a brake shudder. Loose wheel bearing, worn ball joint, worn tie rod or tie rod end, worn control arm bushing, etc, etc.
They should be inspecting all of this if they haven’t.

There’s a reason why a worn suspension part of wheel bearing may appear to be a hit and miss thing and not manifest itself right off the bat.

I was going for wheel bearing too.

I’m leaning toward a sticky caliper not fully releasing. Those “long weekend trips” you mentioned could be generating enough heat from that friction to be warping even good rotors. As could the 2,000 miles worth of local driving.

I’m willing to bet that if you were to try to push in the pistons to change the pads you’d discover one stuck.

I’ll also side with those that suggest finding a new shop. This isn’t rocket science…and sanding down the rotors is something I’d be embarassed to even suggest.