Attempting to get into motion and actually accomplish something tangible I decided yesterday to try to bolt on the new Spiegler rotors I picked up for the blue bike.

Having done this kind of work many times before I figured it would take me a maximum of an hour and a quarter to do.

Man was I wrong.



Note the corrosion on the hex head screws holding the ABS sensor ring in place. These are the same screws that have been on this bike for nearly 20 years. Earlier this year Yun and I replaced the roached stock rotors with the EBC replacements that had finally arrived.At that time the screws were fine.

The only thing I can guess is that there must be some kind of dissimilar metals thing going on since the EBC carriers are made of a different material than the stock carriers. These screws were in so tightly now matter what we did they did not budge. Four hours later, we were forced to drill them out to get the sensor ring off.

On Monday or Tuesday I'll run up to Bob's to get the right screws so I can bolt the new rotors on.

It looks like the EBC rotors may have failed because I didn't bed them in properly at first? I did light braking for the first 500 miles before cranking on it but my guess is that wasn't sufficient. The Spiegler rotors come with a pretty detailed set of bed in instructions that I'll follow exactly.

Once this is done my hope is I'll have decent brakes on the blue bike again.

Just wondering, were they anti-seized, or thread lockered when installed?

Originally they had loctite red from the factory. I used loctite blue. The first time around they came off with a little heat. This time they were fused so tightly they didn't even spin when we drilled them out. Hard core corrosion.

... which I guess is a testament to the metallurgy that BMW uses. Even after all these years there's hardly any corrosion on the bike anywhere ... and in 8 months bolting on EBC aftermarket parts and suddenly I have a corrosion problem for the first time ever ...

Galvanic corrosion sucks, especially when it's a surprise. Sounds like maybe some galvanized/plated steel in an environment with aluminum or magnesium alloys. That's what it looks like from the pics.

You should borrow some zincs from the boat

This was the week for that kind of surprise maint apparently. The primary disk drive on my main computer at home had a head crash this past week. Toasted the disk. Luckily I do 2x daily backups but still a complete pain in the butt to reinstall everything.

ok...so this is a little dorky..but looking at the picture got me thinking because from outside appearances all the mounting hardware looks the same. You mentioned doing a repair that involved changing the components, and that the corrosion was accelerate after that. It was unusual to me that only those fasterns seem to be effected even though there are a number of others that are in contect with the same metals and coductive surfaces. I found this interesting article on the type of galvanizing used on BMW fastners and that they changed fairly recently:

It isn't explicitly addressed but it's possible that the plating used on those bolts was incompatible (from a galvanic perspective) with the new metals introduced in your last installation.

Thanks for the link. Very interesting.

To confirm, the new bolts I picked up do have a different coating on them than the originals. It was pretty impressive how intensely the old bolts were in there. Even drilling them out they did not spin at any point. Nuts.

From the "feel" of the EBC rotors my impression is the metal is of a different composition and is, to my unknowledgeable eye, not nearly of the same quality.

The Spiegler rotors use the original carriers so this corrosion problem should not recur. I'm curious to see how well the new rotors/pads work.

I do hope this will finally resolve my brake issues on the old blue beast.