MidAtlantian

The side with no obvious way to remove the brake mechanism.


The side with the hex bolt: easy to remove.
I have an old Muddy Fox mountain bike. The rear brake mechanism is different on the left and right sides. One is secured by a conventional hex head bolt. The other side has no (obvious) way to remove it. I am looking at a flat metal surface with perhaps a 0.5mm round edge. I can see that the frame has the same arrangement on both sides; that is, that it is probably screwed into, but do not see any way to remove the mechanism. Help!

Kovkov

I think i can see a cap on the pic with the “round thing”. Try prying it off. It might
reveal an allen bolt.

Andrew R Stewart 

It would be a shame if someone had ground down the bolt's head after installing it. One could try a screw remover (Easy Out) if conventional methods fail. Andy

Moe Zhoost

Perhaps the head sheered off during a removal attempt, though it looks like it was ground down (or rounded over by vise grips). Maybe it's time to get out the drill and EZ-Out. Use some penetrant and allow it to soak in before you try. The threaded part of the bolt is probably 6mm so use a suitably sized bit and be careful that you drill in straight to avoid damaging the boss threads.

UniChris

Do check the cap idea, or even that what you are looking at might be some crud-filled socket head.

Failing that I'd wonder about filing off the head, pulling off the arm, and then trying vise grips on the stud.

But does it really need to come off? Or can you work with what is there using new pads, cables, whatever.

You could also take apart the bolted side and see if you get a sense of what you are dealing with. I guess it is possible it was originally some kind of peened rivet and the bolted side is the one that has been reworked.

What's the situation on the other end of the bike?

mixteup

I keep a small pair of sharp, curve jaw vise grip (genuine Vise Grip brand) pliers for just that kind of thing -
That looks like enough meat left for them to grab - I'd have it out in a jiffy with those, no drilling needed.
Buy a new bolt, after.

MidAtlantian

Hi,

Kovkov was not so far off - but far enough. Whoever did this was ... um... a combination of adaptive and incompetent. The flat surface i was looking at must have been a sort of sheet metal rivet. I was able to pry it off, but it fell apart in the process. Inside of that, it looks like the former "mechanic" lost the bolt, or trashed the threads, and put in a combination of thin self tapping screws to hold the mechanism on - and I was not able to get them out. In the end, I too did a bad job and simply hammered the new mechanism on. It feels as if it will not come loose, and unless I try to brake while rolling backwards, there are no forces on it that would pull it off. (hehe). This is for the back brakes, and most braking usually comes from the front, and this is a bike I use "on occasion". But I am not really pleased with the outcome. I will find another thin self tapping screw and a large washer to help restrain the mechanism from .... falling off.

Certainly, I have never seen anything like this!

Thanks to everyone for their suggestions.

MidAtlantian

I forgot to mention that after the small screws had been tightened into the larger whole, the ends had been cut off. I suppose that was to leave a small hole to hammer the body rivet into .

Moe Zhoost

Wow! Good luck.

Dan Burkhart 

Well, at least the fact that it is the rear brake means that it only has to keep it on the post, not resist forces trying to push it off. Would be a whole other story on a front brake.

AnkleWork

Until you have to stop facing up-hill.