So Ive managed to round off 3 of the heads of the bolts holding the disc carrier to the wheel.

Tried regular dousing of WD40, heat & drilling (but those bolts are a bugger to drill) alas to no avail.

Any ideas / useful tips for removing?

Try a 50-50 mix of acetone and ATM fluid, heat, let it cool, spray and heat, cool, spray and heat. Sometimes tightening slightly then loosen alternating along with the spray and heat will work. On the rounded nuts buy the correct sized nut splitter if you do one side first 3/4 split then rotate 180 deg  and split all the way sometimes you can save the bolt.https://www.bing.com/images/search?q=Nut+splitter+tool+images&qpvt=Nut+splitter+tool+images
Regards Martin.

Thanks for that Martin,

Never seen that tool before!

I'm not sure Id have enough access to the head of the bolt though to be honest. The head is rounded and the LH side access is further hampered by the ABS ring (I can guarantee those smaller hex heads will round too, if I try to take that off)  

Is the wheel removed, if not you might have more access with it removed. The only other thing is to carefully use a burr grinder, Dremel style tool and carefully split the nut. Bought a nut splitter about 30 years ago and used it four times but glad I bought it, it does comes in handy.
Regards Martin.

They are put in using red loctite, you have to heat them.

RicK G wrote:They are put in using red loctite, you have to heat them.

A lot...

Slot it with a Dremel and use a big screwdriver with Vise-Grips.

Swearing a lots helps. It doesn't make it turn any easier but is cathartic.

Not long ago I changed the disks on the front of my K1100 and on initial attempts to remove the hex head bolts holding the disk to the carrier there was no chance they were going to move (but I stopped loading up the hex drive before I rounded them out), so I suspected red loctite that BMW are fond of.

So after some internet reading I found a method of heating the loctite that worked a treat. First get a cheap allen key of the right size for sacrificial use. Then get your proper hex drive or good quality allen key and a heating source such as a gas torch.
Put the sacrificial key in the bolt head and heat up the opposite end to glowing red and hold it there for a bit. I didn't let the end in the bolt head get up to red. The heat will transfer down the key into the bolt. Quickly pull the sacrificial key out of the bolt with pliers and insert the good drive or key and undo. Each of mine let go with a bit of a pop and I was able to keep unscrewing the bolt until it came out.

Maybe I was lucky. On reassembly it was blue loctite for me.

Cheers

Thanks for the useful words guys.

I managed to get 3 bolts out initially and they're clean as a whistle - no sign of any Loctite. Maybe a previous owner put them in clean??

Too extract the remaining 3 botched rounded heads (Ive not attempted the other side of the wheel yet), I'm gonna try the Irwin Bolt Grip method, as a guy on youtube seemed to have positive results. Not that that means I will 

Irwin

Success! 

That Irwin Bolt Grip kit is a great bit of kit. Cost £22 (& I hope Ill never need it again), but I simply selected the appropriate sized bit, tapped it on to the mangled heads, put my weight over it & turned. Viola - all three bolts came out. Didn't even need to heat it.

Thanks again for your input guys. All the best 

What size Bolt Grip socket did you use?

The 13mm I think Duck.

Ill check in the garage tomorrow to confirm 

Yep. 13mm & 1/2''.

MartinW wrote:Try a 50-50 mix of acetone and ATM fluid

Absolutely no use whatsoever. The mixture should be 50/50 ATF and trichlorethylene, but good luck on finding the latter without a special licence these days. In its collective wisdom the internet has been misrepresenting the acetone/atf mixture as being the best penetrating fluid for years.

(...)appeared in the February/March 2010 issue of Machinist’s Workshop. The following is Lloyd W. Bender’s reply:

The original homemade penetrating oil mixture called for using trichloroethelyne as the solvent. I cannot recommend trichlor for home shop use and definitely not for anything slightly resembling a business. Both PSF and ATF will form emulsions with acetone under mild agitation sufficient to thin the oil enough to penetrate. Upon standing, these will separate. Acetone performs better than the other commonly available organic solvents, such as methanol, but not as well as trichlor.

If you Google 'Lloyd W. Bender's reply' you'll get no end of links to the original article.

I use Kroil. Dammed expensive, but in tests of commercially-available penetrating fluids it usually comes out on top. It even freed LFB's clutch arm...

Thanks Dai I meant ATF. See the following comparison.http://www.popularmechanics.com/cars/how-to/a6064/wd-40-vs-the-world-of-lubricants/
Regards Martin.

Leprechauns.

Just to follow up on this thread.

I got a set of the Irwin Bolt Grips and they work like magic.  Just tap it on and throw a ratchet on and the bolts with stripped heads come right out.

In the past I've wasted many hours getting those damned disk carriers off.  Wish I'd had these long ago.

And when putting the carriers back on I use M8x25 stainless buttonheads and anti-seize.

Hi Duck, thanks for the reminder I have also just ordered a set, Black Friday gift to myself.