Grinding under deceleration

[nazgul350r]

I have a grinding sound coming from the front of my 9 while decelerating.

Any ideas?

Tow truck is on the way already.

 

[benben01]

Transmission maybe???? Let us know what the dealer finds.

 

[nazgul350r]

I dont think its the trans, because it is lessened while the brakes are on.

Will let everybody know.

 

[CX9 SportOwner]

A reminder to all.

Include your vehicle details. Year, Trim, AWD/FWD, Options, Color, etc...

 

[nazgul350r]

Mazda fixed the car this morning. Said that the pads had rusted and that the rotors were slightly warped.

Is this going to be an ongoing problem? I sure hope not.

I have 1200 miles on the car and its a FWD.

 

[CX9 SportOwner]

Sounds like it was sitting in a wet environment for an extended period of time.

26K on our original pads and no problems. Still lots of pad left.

 

[nazgul350r]

I got a little more detail when I picked the car just now. The CX that we bought had been on the lot for about 10 months. As you can imagine it was not moved much and as such the rotors where the brake caliper were at built up rush which caused brake pad material to build up at the location. As we drove it more it caused more build up which led to the warped rotors.

But all was fixed under warranty.

 

[ceric]

If you had said "braking" instead of "decelerating", the diagnosis could have been more precise. Glad that the problem is fixed. Japanese vehicle, unlike German, use hard steel rotors. The pro is it lasts longer, the con is it warps (inc. buildup). German vehicles such as BMW and MB use soft steel. The rotors are designed to wear as fast as the pads. Therefore, you have to replace BOTH (rotors and pads EVERY TIME).
The pro is it does not warp as easily. The cons are (1) expensive to maintain (2) lots of brake dust on the wheels.

 

[CX9 SportOwner]

I'm happy with the factory setup. Good life, some noise, but not a lot, good braking (especially with my new tires), and almost no brake dust. Anyone seen a BMW that didn't have brown wheels?

 

[nazgul350r]

I usually replace the rotors on my cars when I change pads, it about as cheap as turning them and easier too.

 

[ceric]

I usually replace the rotors on my cars when I change pads, it about as cheap as turning them and easier too.

"as cheap"? No, not with German vehicles.

The MSRP is about $1000 per axle (inc. labor).
If you are lucky, you pay $800 after discount.
That is why BMW offer FREE MAINTENANCE for 4 years (incl. scheduled ones).
They call it "Break My Wallet" for a reason. MB is the same w/o free maintenace.

For Japanese vehicles, usually it takes two pads to wear one one rotor.
You save some $$$ and less brake dust on the wheel.

 

[nazgul350r]

Thats why I do it myself. About $400 to $500 in parts for all four wheels.

 

[wontonjon]

I'm happy with the factory setup. Good life, some noise, but not a lot, good braking (especially with my new tires), and almost no brake dust. Anyone seen a BMW that didn't have brown wheels?

me...mine have more of a matte black look!