I'm trying to remove the front brake caliper from my Specialized Allez. It took me a long time, a lot of effort, and plenty of 3-in-1 to finally loosen and remove the recessed nut that screws onto the caliper bolt. I expected that the caliper would then come off the forks with ease but unfortunately this didn't happen. Am I missing something here or should the caliper be able to be removed when the nut is undone and removed from the bolt? As I mentioned, the recessed nut was really difficult to remove and there was a bit of rust around it. Maybe the bolt has rusted to the forks too. If so, any tips for removing the bolt and caliper?
Sounds like the brake caliper bolt is corroded in place. If the bike has been used on a trainer or if the rider is generally a profuse sweater, this can happen. It could be the result of road salt or just general longterm exposure to the elements as well.
I would use some sort of penetrating oil, or maybe Liquid Wrench or PB Blaster on the affected bolt and let it sit for a bit, then take a punch- or whatever you have that resembles a punch, such as another bolt- and try lightly tapping the caliper bolt out from the back of the fork. Don't go to town on it as you don't want to damage the brake caliper or the fork. I'd be awfully surprised if this didn't get the job done.
Once the caliper is free, cleanup whatever penetrating oil you used along with as much of the corrosion as you can. Upon re-assembly, apply a very light film of grease to ouside of the brake bolt and the non-threaded section of the caliper bolt. Though not necessary, small amount of blue Loctite (or a comparable workable threadlocker) on the caliper bolt threads will not only help keep the bolt in place, but also helps prevent corrosion between the nut and bolt. These steps should help prevent this from happening next time.
A a side note. I once had a similar problem but then I couldn't get my recessed nut loose.
I removed the brake pads. After that I could twist the whole brake assembly until I managed to "screw it out" of the nut. Then I screwed in a screw into the recessed nut and carefully knocked it out of the frame with a hammer.
Old post but I had the same problem today removing a linear brake caliper from the steel post. The most likely problem, if the caliper rotates on the post, is over tightening of the hold-down bolt. My post was slightly mushroomed at the top and prevented the caliper from sliding off the post on either side. The best way would be to use a small center hub puller on the bolt head, but without that I ended up slightly filing/grinding down the head of the post until I could use a screw driver and hammer to tap off the caliper. Look for mushroom of post head if the brakes are old or over tightened.