Scuffing rotors

mike519 · 07-07-2013, 05:54 PM

On a recent wash, it looks like some water sat behind the pads somehow and the next morning, when backing up, the brakes stuck a bit and I have had a minor jutter since then. I have tried bedding them in again (though not aggressively yet) but no change. I have thought about just taking a sanding disc on an angle grinder and lightly scuffing the rotors to remove any deposits.

Any thoughts on this? Has anyone done it?

Thx

dubsesd · 07-07-2013, 06:27 PM

i wouldnt suggest it. maybe some brake cleaner on the rotor and take it for a good thrashing...

Caddyshk · 07-07-2013, 06:29 PM

I always make a few braking runs after washing the car. Even after that from time to time they get rusted on; including yesterday AM - never had a lingering issue however...

seank · 07-07-2013, 07:04 PM

Quote:

Originally Posted by Caddyshk

I always make a few braking runs after washing the car. Even after that from time to time they get rusted on; including yesterday AM - never had a lingering issue however...

WHS

StickMon · 07-07-2013, 08:06 PM

Never had rotor issues, but my parking brakes routinely get stuck the morning after washing.
Again, no lingering issue after they pop loose.

yousefnjr · 07-07-2013, 08:42 PM

A very light sand might be ok, but I would be scared to do any sort of powered grinding without a dial indicator. If the surface is left uneven it could make it vibrate under braking. I'm not sure of the rotor runout specs for the the car, probably a thousandth or two. There's a chance it might be stamped on the rotor housing. As others have said though, a quick drive around the block after washing is probably easiest.

mike519 · 07-07-2013, 09:20 PM

Quote:

Originally Posted by yousefnjr

A very light sand might be ok, but I would be scared to do any sort of powered grinding without a dial indicator. If the surface is left uneven it could make it vibrate under braking. I'm not sure of the rotor runout specs for the the car, probably a thousandth or two. There's a chance it might be stamped on the rotor housing. As others have said though, a quick drive around the block after washing is probably easiest.

Oh, I wasn't planning on any deep sanding...just a surface scrub. I doubt it would take off even a thou.

I often do a run after washing but in this case, I was going to polish and seal the next day so did not want to risk getting any dust/dirt/etc on the paint to save from a rewash the next day.

The HACK · 07-08-2013, 02:13 PM

Problem should go away after a few days if car is driven regularly. Rust, unless it's built-up rust on the same spot, will get ground off by the pads eventually. Unless you take the car right now with the high rust spots to the track, i wouldn't even worry about it.

The problem is the hill start holder, if you're parked in an incline, the car automatically puts pressure on the pistons to hold it in place, therefore the pads contact the rotor as you park overnight. End result is, if the rotors are wet, you'll get a rust spot.

A couple of tips in this thread is spot on though. After each wash I take the car out for a good 5 minutes with some moderate to heavy braking just to dry the rotors up. And I NEVER park the car with parking brakes after a wash after the FIRST time I did that on my 323Ci. Took quite a bit of effort with that 173HP engine to break free of the rusted on shoe to the drum.

Phishman · 07-23-2013, 08:33 PM

About 2 weeks ago I washed my car but had to pull in the garage immediately because it had started raining. 3 days later I took it out for a spin and noticed it felt a lot like when like when my calipers were seizing (replaced 2 in the last year). Does anyone know a way to tell the difference between the two? I jacked it up and the wheel spins freely but you can hear a slight "rub". I was worried I might end up warping my rotors if it was the caliper.

07-07-2013, 05:54 PM	#1
mike519 Captain 130 Rep 832 Posts Drives: 2018 M240i Join Date: Apr 2012 Location: Waterloo, Ontario iTrader: (0)	Scuffing rotors On a recent wash, it looks like some water sat behind the pads somehow and the next morning, when backing up, the brakes stuck a bit and I have had a minor jutter since then. I have tried bedding them in again (though not aggressively yet) but no change. I have thought about just taking a sanding disc on an angle grinder and lightly scuffing the rotors to remove any deposits. Any thoughts on this? Has anyone done it? Thx
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07-07-2013, 06:27 PM	#2
dubsesd #dubspec 6336 Rep 5,201 Posts Drives: G05 X5/ 2016 F80 M3 INDVL Join Date: Jul 2011 Location: Ottawa iTrader: (2)	i wouldnt suggest it. maybe some brake cleaner on the rotor and take it for a good thrashing... __________________ LCI ///F80 M3 Individual Atlantis Metallic / Black Full / Carbon Cermics / 6MT MPE / M Performance & Carbon package / KW v3 / 20" HRE R101LW / 20" HRE 527s / Michelin PSS / 20% tint / 3d Design / Streckenn splitters / OEM GTS hood / EAS Carbon seatbacks / Carbon RKP sideskirt / Bootmod3 / M Performance Tri color alcantara / AWE S Flow instagram: @ dubsesd Last edited by dubsesd; 07-07-2013 at 08:08 PM..
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07-07-2013, 06:29 PM	#3
Caddyshk M = Midlife Crisis 65 Rep 2,006 Posts Drives: 2006 Z4MC Interlagos Join Date: May 2007 Location: Fort Erie, Ontario, Canada iTrader: (0)	I always make a few braking runs after washing the car. Even after that from time to time they get rusted on; including yesterday AM - never had a lingering issue however... __________________ 2006 Z4MC - #LL93158 SS Race Cans, RE X Pipe, DKF Sec 1, Fabspeed Headers, OE STB, AS Shifter, Dave Z CDV, GC Coil Overs, Stoptech lines, Hawk DTC Pads, RE Clutch Stop, RE Transmission Mounts, Vibra-Technics Engine Mounts, Poly FCAB & RTAB, LeatherZ M Shift Boot, Tekarbon Rear Spoiler, CF Grills, Advan RS DGM
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07-07-2013, 08:06 PM	#5
StickMon My other car is on Mars 636 Rep 3,124 Posts Drives: 2006 MR Join Date: Feb 2011 Location: Lo-Cal iTrader: (1)	Never had rotor issues, but my parking brakes routinely get stuck the morning after washing. Again, no lingering issue after they pop loose.
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07-07-2013, 08:42 PM	#6
yousefnjr salty cowboys fan 6158 Rep 3,406 Posts Drives: ‘06 Z4MR, ‘20 X7, ‘22 M4x Join Date: Dec 2012 Location: Bay Area, CA iTrader: (2)	A very light sand might be ok, but I would be scared to do any sort of powered grinding without a dial indicator. If the surface is left uneven it could make it vibrate under braking. I'm not sure of the rotor runout specs for the the car, probably a thousandth or two. There's a chance it might be stamped on the rotor housing. As others have said though, a quick drive around the block after washing is probably easiest.
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07-08-2013, 02:13 PM	#8
The HACK Midlife Crises Racing Silent but Deadly Class 1821 Rep 5,337 Posts Drives: 2006 MZ4C, 2021 Tesla Model 3 Join Date: Oct 2007 Location: Welcome to Jamaica have a nice day iTrader: (1)	Problem should go away after a few days if car is driven regularly. Rust, unless it's built-up rust on the same spot, will get ground off by the pads eventually. Unless you take the car right now with the high rust spots to the track, i wouldn't even worry about it. The problem is the hill start holder, if you're parked in an incline, the car automatically puts pressure on the pistons to hold it in place, therefore the pads contact the rotor as you park overnight. End result is, if the rotors are wet, you'll get a rust spot. A couple of tips in this thread is spot on though. After each wash I take the car out for a good 5 minutes with some moderate to heavy braking just to dry the rotors up. And I NEVER park the car with parking brakes after a wash after the FIRST time I did that on my 323Ci. Took quite a bit of effort with that 173HP engine to break free of the rusted on shoe to the drum. __________________ Sitting on a beat-up office chair in front of a 5 year old computer in a basement floor, sipping on stale coffee watching a bunch of meaningless numbers scrolling aimlessly on a dimly lit 19” monitor.
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07-23-2013, 08:33 PM	#9
Phishman Second Lieutenant 8 Rep 283 Posts Drives: Beige car Join Date: Nov 2010 Location: Cincinnati iTrader: (0)	About 2 weeks ago I washed my car but had to pull in the garage immediately because it had started raining. 3 days later I took it out for a spin and noticed it felt a lot like when like when my calipers were seizing (replaced 2 in the last year). Does anyone know a way to tell the difference between the two? I jacked it up and the wheel spins freely but you can hear a slight "rub". I was worried I might end up warping my rotors if it was the caliper.
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