E92 BMW Brake Disc Retaining Bolt Rounded

[HughiusMaximus]

Afternoon all,

As the title suggests... was trying to change the front discs and pads on my 335 BMW yesterday and everything was going well until it came to loosening the retaining bolt on the disc.

Its a 6mm hex bolt, and rounded as I was trying to remove it.

Any advice on how to get it out or will I justadmit defeat and take it to a garage?....

Any advice welcome!

[HughiusMaximus]

Just saw a similar thread below so feel free to ignore!!

Sorry.

[imagineifyeswill]

I think you,ll find the similar thread is about countersunk disc retaining screws, slightly different from yours. Ive found with these allen headed screws what often works is to hammer in a very slightly bigger torx driver.

[HughiusMaximus]

Thanks.

I beat a hasty retreat on Saturday and said I'd look for a solution and try again this weekend.

I'll give it a good blast of heat first to hopefully break the seal and then try hammering in the Torx.

Worst case I'll resort to the angle grinder as per below.

[PositronicRay]

I've one of these rounded hex bolts as well. I haven't tackled it yet, what's to stop me just drilling it?

[andyiley]

Ive always found the best way with things like this is to go nuclear straight away.

Drill the head off, remove the disc, if then the stub comes out great, if not grind it flat, then drill & tap a fresh hole.

[AW10]

Or use the corner of a chisel on alternate points around the outer face to try to "turn" the bolt. Often times the repeated taps are enough to break the bolt loose. They're usually under minimal tension which helps.

[BigTom85]

Definitely use some impact and or heat to help break the corrosion and friction between the casting and the fixing.

Hammering in a torx could well do it, if not I find a spring loaded centre punch to mark the centre followed by a 4mm left handed drill bit works a treat. Normal the drill will bite quite quickly and withdraw the fixing.

[col68]

Bmw/mini disc retaining fixings ,always tend to heat first and then use an impact driver, once rounded by not following this procedure then it's a drill out/re tap case..

[PositronicRay]

BigTom85 said:

Definitely use some impact and or heat to help break the corrosion and friction between the casting and the fixing.

Hammering in a torx could well do it.

Just tackled this liquid wrench and a torx hammered in did the trick. many thanks.

[HughiusMaximus]

I tried all the suggestions and then ended up going nuclear and using the angle grinder....

Partial stub left but no way in getting that out easily.