03-22-2017, 08:49 AM | #23 |
Captain
143
Rep 671
Posts |
Have you thought about getting a dial caliper and checking the thickness of the rotor and pads yourself to make sure both are good?
__________________
'20 240ix convertible
|
Appreciate
0
|
03-22-2017, 08:49 AM | #24 | |
Private First Class
45
Rep 116
Posts |
Quote:
My exhaust tips did the same exact thing as well. I just used some high temp spray paint (spray the paint onto a piece of card board and brush it on with a foam brush). Worked like a charm. |
|
Appreciate
0
|
03-30-2017, 06:21 AM | #25 |
Major
271
Rep 1,091
Posts |
OK guys, so to update you: I did just over 1,000km and both rear rotors still haven't been cleaned! Of course they do not look as ugly as in the pic in my OP - but still, there is a very distinct boarder between the inner part (which is basically clean as for normally used brakes, and looks like the front rotors which have both been cleaned and polished over their entire surface by the pads) - and the outer "band" which is still looking differently...
Can't comprehend how this is happening given the pads are planar (so said the dealer who has inspected them, and so they must be - otherwise the front rotors wouldn't have gotten cleaned, either). Any possible explanation? Piotr
__________________
previous: 2003 E46 330i SMG
just sold: 2013 F10 528i xDrive my AWD beater: 2015 Golf R mk7 DSG my RWD pirate & long-distance cruiser: 2015 M235i AT8, LSD |
Appreciate
0
|
03-30-2017, 12:29 PM | #26 |
Car Geek
4131
Rep 3,829
Posts |
Under normal use the brake discs/rotors will last about 100,000 km and will have worn less than 1mm each side. 1,000km of normal use will remove about 0.01mm of rotor (about one tenth the thickness of a sheet of paper), so if the pitting from the rust is deeper than that, it won't have worn off yet.
Although the procedure is at your own risk, a good brake bedding should remove a few hundredths of a mm of rotor. Personally I brake from 110 to 10 km/h as many times as it takes in quick succession for the brakes to just start to fade (brake smell and pedal just starts to get soft), as previously mentioned, drive around to cool the brakes after such a session (at least 15 mins of highway driving) without allowing the car to come to a complete stop. It likely rusted and pitted originally just in the outer band due to salty water just on that band when the car was parked. The reason the corrosive mixture is only on the outer band is due to the previously mentioned effect from the spreader spring in the caliper that pushes the outer edges of the pads apart, causing them to drag more on the inner part of the rotor than the outer edge when the brakes are not applied. Last edited by aerobod; 03-30-2017 at 12:49 PM.. |
Appreciate
0
|
03-30-2017, 11:57 PM | #27 |
Major
271
Rep 1,091
Posts |
Thanks aerobod - your explanation makes sense to me, at last! The clue being that the uneven cleaning doesn't actually occur while applying (moderate) braking, but with constant dragging of pads against the inner rotor's area...
Will do the bedding procedure, but - since it involves some "smearing in" between the rotor and pad materials - I'll only do it after my rotors are (almost) free from any remnants of iron oxide Piotr
__________________
previous: 2003 E46 330i SMG
just sold: 2013 F10 528i xDrive my AWD beater: 2015 Golf R mk7 DSG my RWD pirate & long-distance cruiser: 2015 M235i AT8, LSD |
Appreciate
0
|
04-10-2017, 12:44 PM | #28 |
Registered
0
Rep 2
Posts |
DIY for painting calipers?
Hi Rayscott. Can you point me to a thread (if one exists) or to an external DIY resource for repainting my brake calipers? Trying to decide if this is worth doing. Mine (a 2011 E93) look horrible -- but I'm reluctant to drop a ton of money on new ones. Any suggestions would be appreciated.
|
Appreciate
0
|
04-11-2017, 10:01 AM | #29 | |
Major
271
Rep 1,091
Posts |
Quote:
Piotr
__________________
previous: 2003 E46 330i SMG
just sold: 2013 F10 528i xDrive my AWD beater: 2015 Golf R mk7 DSG my RWD pirate & long-distance cruiser: 2015 M235i AT8, LSD |
|
Appreciate
0
|
04-11-2017, 10:57 AM | #30 | |
Major General
3105
Rep 5,582
Posts |
Quote:
do you know how to change pads and have the tools? because at this point I would lift one side of the rear, remove wheel, remove pads and inspect them for even surface along the entire pad length, maybe even remove caliper and clean the pins and slides and reassemble everything, then do the same on the other side. And I'd clean the rust off the disc with soap and water and a brake pad as a abrasive. I'd also inspect the inner side of the disc to see it looks the same - not sure if inner visible when mounted. |
|
Appreciate
0
|
04-12-2017, 12:32 AM | #31 | |
Car Geek
4131
Rep 3,829
Posts |
Quote:
|
|
Appreciate
0
|
04-12-2017, 12:40 AM | #33 | |
Major
271
Rep 1,091
Posts |
Quote:
Piotr
__________________
previous: 2003 E46 330i SMG
just sold: 2013 F10 528i xDrive my AWD beater: 2015 Golf R mk7 DSG my RWD pirate & long-distance cruiser: 2015 M235i AT8, LSD Last edited by moldcad; 04-14-2017 at 02:20 AM.. |
|
Appreciate
0
|
04-13-2017, 01:32 AM | #34 |
Car Geek
4131
Rep 3,829
Posts |
It is definitely unusual, but from the fairly aggressive pitting could be caused by a chemical that is somewhat acidic or alkaline, perhaps a new type of road de-icing chemical that has been used in your area?
|
Appreciate
0
|
04-13-2017, 10:33 PM | #35 | ||
Major
271
Rep 1,091
Posts |
Quote:
Quote:
Piotr
__________________
previous: 2003 E46 330i SMG
just sold: 2013 F10 528i xDrive my AWD beater: 2015 Golf R mk7 DSG my RWD pirate & long-distance cruiser: 2015 M235i AT8, LSD |
||
Appreciate
0
|
Post Reply |
Bookmarks |
|
|