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Re: $%&^* rotor hex screw

>Spent Sunday trying to change the front brake pads and rotors on my
>1990 325i Conv. A seemingly easy job was thwarted by the 5mm hex head
>screw that attaches the rotor to the hub.

Ah YES - the old rotor screw problem!  I should put this one in the
FAQ.

The best solution to get out a stuck one is an impact driver - the
kind you hit with a hammer - with a hex socket.  Don't try to get it
with one big blow, rather use several medium blows.  If you havn't
already stripped the hex hole in the head of the bolt, it will
probably work.  If not, you can drill the head off pretty easily
because the bolt is soft.  That will get the rotor off, then you can
use vise-grips on the bolt stub, or use a smaller bit to drill out
the body of the bolt.  You just have to be careful not to kill the
threads in the hub.

When you put a new one back in be sure to take some preventative
action for next time.  I've found that if I use anti-seize on the
bolt (not a lot, so it doesn't fly out onto the brake surface!),
especailly under the head, it helps.  The other trick is not to
tighten the bolt very much.  I make it just snug enough to hold the
rotor in place while I reinstall the caliper, and no more.  Once the
wheel is on, the bolt doesn't do anything.  The lug nuts hold the
rotor.  It won't loosen and fall out, because the wheel fits over
it.  With that combination I've always had an easy time getting them
out again.

good luck!
rick
'87 325es
'90 325iX