Removing BMW brake disks...

[Mark_bt52]

...when the stupid locator screw has rusted itself into the hub!

What a stupid idea. Why didn't they just go all the way and weld the disks to the hub

Simple task made difficult by having to drill the screw out.

Basically, this:

[mik]

[Mark_bt52]

Is that a reverse thread extraction tool?

If so, tried and failed.

[mik]

No - it’s an impact driver (before that name started to be used for a different tool )

Put the appropriate bit in, and smack it with a hammer - which causes it to turn a very small amount (maybe 10degrees?) whilst it is being driven into the screw head - works great on these fookers.

[mik]

[Mark_bt52]

Ah I tried something like that, but it just destroyed the screw head without turning it.

Ironic that the only purpose of the thing is to try to make life easier for lining up the disk with the hubs

[Swervin_Mervin]

Every car I've ever worked on has had these.

One of my first memories of working on cars with my Dad even - soak in WD40 or Plusgas etc, then whack with an impact driver as per Mik's post. I think an impact driver might have been one of the first tools I bought once I left home even!

[mik]

I don’t think I have ever struck one as gently as the bloke in that vid

But yeah - very rare that a screw won’t yield to one. I learned early on that you can use them to mash-up screw heads if you don’t “take up the slack” by rotating it first so that the force goes right into the screw when you smack it.

[V8Granite]

The ML had a fully comprehensive Mercedes service history so you can be sure it came out like butter......

No, the screw head snapped off

I’ve never had an awkward one, they either fly out or are stuck there forever.

Dave!