HI everyone,

I'm actually working on my K100, and I saw the 2 screws holding the rear brake disk are completely destroyed...



It seems my rear disk is around 0,39mm, I guess it's good to be replaced?

But with this destroyed screws, any idea how I can remove them?


Thanks,

A lot of heat to start with as the bloody things are held in with Loctite (stupid idea on BMW's part). Then try the following:

1. Get a 1/4" Allen bit and slightly chamfer the leading edges so that you can feel the head of the bolt when you put the two together. Hammer it in and don't be gentle. This should reshape the head of the allen bolt and get a good grip at the same time as 1/4" is 0.25mm bigger than the 6mm head.

2. Drill the head off. Start with a 6mm drill because you just want to remove the head. The drill should self-centre. Once the heads are off, knock the disc off and file small flats on either side of the bolt to take a 4.5mm or 5mm spanner. Apply a lot more heat to the remains of the allen bolts, then try the spanner. If they still won't come out (unlikely at this point), grip them with a pair of good quality mole (vise) grips.

I've had success with both methods. Do not Loctite the new bolts in. You'll need to order them from a BMW dealer as the head is a non-standard size but clean the blue Loctite off first and apply Copaslip or similar before putting them in. Their only function is to hold the disc in place when you take the wheel off - it's the four big bolts that do the job of keeping everything together when you hit the brake.

Many thanks for your feedback !

I'm hesitating actually to remove the disk, I'm still searching if I have to change it, I don't find the good value of the thickness.

On the disk is written 0,18", but in millimeters it's 4,5mm, but even at the edge of the disk where it's thicker, it's not that tick... so I don't understand what is the correct value.

If I recall correctly, BMW say that it's worn out at 4.0mm. Many of us have run discs that are a lot thinner than that without any problem - Charlie99 (I think???) was running one at 3.0mm. As you have the wheel off and are looking at the problem, I'd attend to it now instead of leaving it until later.

If you have it, you can hammer a 3/8" drive Torx bit into the screws after heating them(a lot).  Torx bits are very hard and seem to have a geometry that bites into the stripped out sides of the Allen hole.

Thanks you

Do you know some replacement part for this disk?

ouafnico wrote:Do you know some replacement part for this disk?

Look down this list at tills.de

I just checked ebay.fr. Some of those sellers are taking the piss - asking almost the same price for a secondhand hand disc as the cost of a new disc.

Prices seems good on tills !

On ebay I checked too, and some are awful...

There is a firm in Greece called tsuboss. they might be worth a look. Sorry no link but a google search will bring them up.

I have never bought a used disc. New EBC discs are good enough price.

I had to change the rear disc on the RS as it escaped the recall for the early slotted rear disc. I used lots of heat before trouching the disc bolts as they were original and in the 35 years. They cam out first shot but the replacements are only hand tight.  They only stop the disc falling off if the wheel is removed.

My K1100LT needs new front discs.........

You could try Thom Hellebreakers in the Netherlands, he's on Facebook,Twitter,Instagram and messenger,