How to loosen Magura Brake Allen Bolt?

Tried searching but couldn’t find anything on it. I’m trying to adjust my magura brake so that the lever is closer to my handle. There is a small allen key bolt to adjust this but I cannot get it loose. I’ve already broken several allen keys trying to get it un-frozen and still haven’t had any luck. Someone at a bike shop told me that they often use loctite on these so that it doesn’t come loose and fall out. Can anyone give me any tips or tricks on how I can loosen it? Any chemicals or heat that may help?

They do use a thread locker on those bolts, but not just to keep them from coming apart. It certainly helps with that, but it also prevents them from seizing, and to ensure that they will come apart. Most likely you have a steel bolt going into an aluminum thread, and at some point an electrolyte was introduced. Steel and aluminum will cause galvanic action that will chemically bond the two dissimilar metals together.

I would try something like WD-40, or a penetrating oil on the end of the bolt that is exposed, and let it penetrate overnight. In the morning try to get it out again. The best would be if somehow you could submerse the part in the penetrating fluid.

If it’s not budging try automotive anti freeze. Again, let it sit overnight to penetrate. This is a tip that I got from Campagnolo for removing seized seatposts without a torch. I don’t know if anti-freeze will cause any harm to other parts, so I wouldn’t recommend it as a first try, but you could do a bit more research to find out if it would be a good solution. When we used it we would pull the bottom bracket out of a frame, and fill the seat tube with antifreeze from the bottom, and let the frame sit over night in the repair stand upside down. I remember it working very well. Sometimes it needed to sit a bit longer, but it was nice to not destroy the paint with a torch.

Thanks for the info. I tried soaking it in acetone but didn’t do the job. Will try the antifreeze or WD40 method next… Anyone else have issues with this?

If its the 2mm allen set screw in the lever blade, I have had some trouble with these too. The penetrating oil usually works. If you cant get it loose, you could just drill it out and retap the lever blade for a larger size allen key, which I’ve done one or twice too. I have good used HS33 levers and lever blades for sale if you can’t get it to come loose.


If Loctite is used to secure that bolt, and you don’t want to destroy the rest of the brake, you might use a high-power soldering iron held against the bolt to try and overcome the bonding action of Loctite.

Look for “Kroil” or “PB Blaster” or “Liquid Wrench” at an automotive supply store if you’re shopping for a penetrating oil.

x2 on the kroll and pb blaster. I restore old cars, and run into this problem often. Apply everyday for a few days. Tap on the screw lightly when you apply it. Try to tighten it then loosen it. Works almost as good as heat.
Good luck Al