The first pic is the front brake. You can see a little corrosion on the outside. The retention screw is seized solid the head of the screw is soft and deformed under pressure.
The second pic is the rear screw which put up a struggle but came out. You san see corrosion on the shaft.
The pads could have done a few more weeks but the customer is going on an overseas trip with lots of climbing.
Ordinarily I would just replace the caliper but don't have one to hand and felt like an experiment. I have managed to drill out the screw with a 3mm drill bit. I will need to clean up the threads with some taps which I'll get tomorrow.
I will put use titanium screws when putting the new pads in. The titanium screws are harder, impervious to corrosion and fasten with a 3mm allen key.
However if I can't clean up the threads in the caliper then I will need to replace it.
This was a common issue when I was doing more maintenance. What solutions have other people got?
by Michael_of_Derry
4 Comments
Shimano need to get in the bin for speccing low quality bolts with only a flat head notch and not an Allen key.
I’ve drilled out two of these and afterwards replaced every bolt I had with a new one.
I can’t believe these ever came with a flat head. Mine are all allen.
They don’t need to be particularly tight since they all use a retention clip or cotter pin. I guess being brakes, people tighten them more for safety.
If the caliper is free you could try using an impact screwdriver but tbh it might be best to slowly drill it out personally I’d just buy new calipers
Looks like corrosion on your brake caliper. Might be a warranty issue. Had my LBS return it to Shimano under warranty. Replaced under warranty by Shimano, no questions asked.