Brake Disc Retaining Bolt Seized

[CypherP]

As the title says really. After 2 hours of both gentle and aggresive persuasion yesterday, I have a seized retaining bolt on the front nearside disc, that is both ground out and doesn't want to budge.

I have tried all methods suggested online, with the exception of drilling the head out and trying to remove the remaining thread. I've tried the double hammer method, impact driver and also using a hex punch to re-mould the bolt head, but the punch I have isn't steel and therefore is starting to disfigure.

Are there any other options I have left, or do I resort to drilling out the head so I can remove the disc and just go from there? I've also read that this retaining bolt is only there to stop the disc spinning when the car was being manufactured. Is this true, and if so, are they needed? I ask because the Brembos I have bought come with new retaining bolts and would like to use them if I can.

[CypherP]

It's on an E46 coupe. I'll try and get an image up a bit later, but its a hex screw that has been rounded out, so an Allen won't fit the head any more.

I'm going to go and buy a new set of Allen keys to do the other 3 later on, just getting so frustrated that the first disc I try to remove just wont budge!

[CypherP]

The frustrating thing is that the first one I came to was already rounded off, so I'm hoping the others aren't either. I'm going to leave some penetrating fluid on them overnight and see whether it frees them up a little.

[CypherP]

OlberJ said:

Impact driver and when it doesn't work, drill them off.

If you leave the thread in then the disc will sit with the thread in the hole and not spin. It's not perfect but saves too much faffing about.

Left handed drill bits are also handy because when you hit a certain point they tend to unscrew themselves due to the heat and vibrations.

Thanks for this. I think this is the final plan this week when I revisit it. If they're not serving any further purpose being there, I'll drill off any that are stuck fast. I've already tried the impact driver route and no joy. The problem being that because the head is already rounded off, the impact driver has nothing to grip when turning.

I'll fire the drill up on Thursday and give it a go.

[CypherP]

jeoff82 said:

The retaining bolt always seemed to get seized on them BMW's. I always drill them out but if i recall the bolt is quite large so need a largish drill bit.

I'll likely be drilling it out, and have now bought some better quality allen bits to remove the others, so hopefully they won't get stuck either. I have a nice new tin of copper grease to ensure I don't run into the same problems a year or two down the line.