My e38 740i discs/rotors....

My 740 failed the MoT test on corroded front discs. I didn't think they looked too bad until I took one off. The outer side isn't too bad but the inner has a lot of rust and the shiny part of the disc is about
half the width. The pad seems to have worn top and bottom and only really contacting in the middle. I've never seen this before.
Here's some pics... (just click on the picture)
http://www.kodakgallery.com/ShareLandingReg.jsp?Uc 3b8m1c.tn7jnes&Uy=-i1ul68&Upost_signin=Slideshow.jsp%3Fmode%3Dfromshare&Ux=0&UVs2218307638_36310293908
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http://www.kodakgallery.com/ShareLandingReg.jsp?Uc 3b8m1c.tn7jnes&Uy=-i1ul68&Upost_signin=Slideshow.jsp%3Fmode%3Dfromshare&Ux=0&UVs2218307638_36310293908
I'd suggest it's caused by the floating caliper not moving freely on the pins. IOW braking pressure is not evenly distributed over both sides of the disc. Mike.
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Mike G wrote:

The caliper moves freely. I could understand if one side was worn more than the other but why only the wear in the middle?
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So what did the pad look like that made the wear pattern on the inboard side of the disc. The wear pattern almost looks like there was no pad installed on that side or perhaps the wrong pad. Having some difficulty interpreting the photos because of the white box in the background causing the rest of the picture to be underexposed.
The assymetry in the new rotor is interesting. Are the inboard pads larger than the outboard??

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Jack wrote:

The inboard pad is a mirror image of the wear pattern of the disc. The pads look fairly new so the PO may have put new pads on the dodgy old discs.
I guess the new disc was made then poorly turned down hence one side being thicker than the other. No the pads are both the same size.
The pcis looks fine on a couple of screens I have but your might be adjusted differently.
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One could speculate that the discs were returned by a prior puchaser because of the asymmetrical thicknesses. I think I might return them for this reason if I thought it wasn't per spec. With these uneven thickness the disc could have a tendancy to warp if overheated. This wouldn't explain why he installed them before deciding to return them but reality is that we can only guess about the history of these parts.

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Jack wrote:

Maybe someone fitted them, bolted them all up but then found the inboard side was binding hence the partial scuffing and scoring as new pads tend to be chamfered.
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