Hello Fellow Maniacs -

Have a 2002 Mini with approx. 46K miles on the clock and getting some
strange noises from the brakes - sometimes a grinding sound, sometimes
a rattling, clanking sound - although the brakes themselves still work
perfectly. Does this mean it's time to replace the pads and/or service
the rotors?

Thanks,
Pete

 

Should be a sensor which tells you when the pads are low but you can also confirm that visually.

To do it visually, locate your brake calipers. For the fronts, they are in the 9 pm position on the driver's side and 3 pm on the passenger side. Look down into the calipers at a slight angle (through the wheel spokes). If you cannot see anything, you can try the other side or have to remove the wheel. You are going to try to find out the thickness of the brake pad material. There are two parts of the brake pad, the backing plate and the brake pad material. From the top of the calipers, looking down you should be able to see the outer side of the brake pad. You should be able to see the difference between the backing plate (smooth) and the brake pad material (usually dark brown and rougher). The color and texture are different. If the brake pad material is less than the thickness of the backing plate, you have to replace the brake pads.

As for the rotors, you are looking for scoring marks and other imperfections on the surface. Is there a ridge near the outer edge lip of the rotor? Run you finger over the rotor surface and if it is very uneven or there are ridges, it might be necessary to either change the rotors or have them resurfaced. Some rotors cannot be resurfaced because it may be too thin. Look at the color of the rotors and if they have a bluish tint/discoloration to them, you have been running the brakes hot and they could have warped.

Next, take off the wheels to make sure the brake mechanism is attached securely. Move the caliper frame back and forth for look for play. They should be no play if you try to move the caliper frame. Look at the back of the rotors for the same visual inspection for the pads and rotors.

Do the same for the rear.

These are the very simple basic tests only. Even if the pad and the rotors look fine, if the noise continues, you have to bring it to a mechanic.

From the grinding noise, I suspect that you have run down your pads and the backing plate has ground into the rotor which may make it necessary to replace both.

If you cannot do this, bring it into a Midas (or someone like them) for them to do a visual inspection. Get it fixed as it most likely would not get better by itself and could severely impact your ability to stop.

 

I don't think the 02's have the sensor so you will have to check the pad and rotor.

 

correct 02 did/does not have sensors

the quick seat of the pants check is right on. here's some visual aides


here's an almost new pad from the same angle you'd have if you look into the caliber from the horizontal position. I've put a little white paint on the backing plate. (you can also clearly see the slot for the sensor used after 02)

Here's a pad needing to be replaced. Notice how thin the material is...about equal to the backing plate.



recommended minimum pad thickness is 3mm

So far as rotors go - there is a minimum thickness stamped on a rotor (Front 20.4mm, rear 8.4mm) and to be SURE you would measure that. MINI/BMW says replace the rotors with the pads - period. You need to consider how deeply yours are grooved - in 'the day' one would always resurface rotors - grind on a lathe to a clean surface (but watch those minimum #s).

Rotors are relatively inexpensive if you stay with plain ol solid rotors and the majority of the labor is already done getting the pads off alone. I typically go two sets of pads to a set of rotors; but I'm pretty easy on brakes in general.

 

Thanks to the OP for asking the question and to slinger and the capt for the very thorough and helpful replies.

 

Capt BJ,

Thanks for the pics. I like the idea of the white paint. I may put a little white paint on my backing plates for a quicker visual.

 

There's a special BMW tool for measuring brake pad thickness. It pokes through a hole in the pad near the caliper, its kind of handy to have one, though a little difficult to track down (like this) and a little expensive for what it is (the price has doubled since I bought it). Before I got that I used my metric set of Allen wrenches as gauges.

For measuring the rotor thickness, I got a cheap set of digital calipers from Amazon (like these ones.) I was amazed how cheap these are.

 

Hi, do you know where I can get original OEM brake pads and rotors? Please send links. I can't seem to find any on the internet, only the after market parts.

Thanks
Janine Zhu

 

Here is a link to our brake pads. Go with some aftermarket pads, at the minimum they will be lower dust.
http://www.waymotorworks.com/maintenance/brake-pads/

If you need help just give us a call.
WAY
www.waymotorworks.com
317.201.8670

 

That digital caliper won't correctly measure a rotor since most rotors a lip worn into the outer edge that is thicker than the lower spots towards the center of the face.

 

I used a washer on each side of the rotor (on the flat part) then measured the width using the washers as a standoff (?), then subtracted the width of the washers them selves. This essentially allows you to measure "around" the lip. It's not perfect, but accurate enough for measuring the rotor thickness, IMHO.

 

I missed this previously. The caliper's jaws have also have a lip, which fits quite handily over the lip of the rotors. They jaws sit flat on the wear surface of the rotors.

 

I use a micrometer instead of a caliper for measuring discs. Works quite well and gets you past the lip to measure the worn surface of the disc.
Here's one under $20 on amazon. They also sell them at Sears.

http://www.amazon.com/General-Tools-...252032&sr=1-52

 

The brake pad sensor only comes up when there is 3 mm or less of thickness left in the pads. You can drive on the street like that for months before you have to replace them.

 

I just tried that, the calipers allowed me to zero out the thickness of the washers, so no subtraction necessary. I got the same measurement with and without the washers, so I'm thinking my calipers do measure the thickness minus the lip.

One thing, it you're using washer like this, don't drop one down between the front disc and the axle. There's a little pocket inside the disc the washer will get stuck in, and its difficult to persuade it out. I finally got it out with a command adhesive sticky pad attached to an icing spatula (thanks to my wife for the idea).