Cervelo Aspero, swapping front disc brake caliper. Got both bolts out, and while putting the bottom bolt in, hit a lot of resistance. I made sure it was straight, no cross threading, and still couldn’t get it to thread in, even the old bolt! I have an m5 tap that I ran to chase the threads, and got a good bit of shavings (it was doing more than chasing the threads, more like dust with some grease and Loctite mixed in)
I’ve pulled calipers before but never run into something like this before. (Sure there was resistance coming out, but I figured it was Loctite) Sweating bullets the whole time, added more Loctite on the new bolt, which threaded in securely.
Can’t figure out what could have happened. The bolt, old or new, threaded in about half way and got the resistance, like it was jamming. Was the original install done poorly? It came out, didn’t seem to want to go back in. There was some raised aluminum around the hole edge. Someone at the factory use an impact driver on it maybe?
Probably a little bit of galling between the old bolt and threads, could be for a number of reasons.
What model year Aspero, brand of brakes, direct or flat mount bracket? Unless it’s an identical model of caliper there is a chance the bolt lengths are different.
maybe a helicoil partially came out? (“There was some raised aluminum around the hole edge”)
I had this once with a cannondale and a lefty fork. The 1 bolt that holds the wheel to the fork came out, partially with the helicoil, but I didn’t saw that. When screwing it back in, I mashed the helicoil back in the fork, and it got stuck and totally screwed..
since I never heard of a helicoil I was in in a total panic, thinking I ruined my 2 weeks old bike 
Got it to the shop and the installed a new coil, worked as it should from then on.
GRX 820 caliper. Adapter mount plate used. I checked it this morning and it’s holding firm. It was just weird.
I’m glad I bought the Park internal routing kit. The double threaded barb tool is priceless!! I taped the hose together, and there was no way to get it through, but the barb got it all through, and helped displace the rubber tubing to get it to slide through easier. They used another one on the mechanical shift cable so I threaded the Di2 wire through it too.
This has been an experience, and it’s not done yet.
The Park hose cutter/insert tool doesn’t cut Shimano brake hose very well. FOr that function, it fails. The insert driver will be tested/used today.
There’s a tool for that. Has anyone used it on their own bikes?