Disk brakes locked after Drop spindles installed

[grumble]

sorry haven't read all responses so may be repeating others

Have you tried to push the calliper pistons right back (2 g clamps is best)
Then replace pads, mount, pump the brake pedal to settle it all
They should find there own position

Sometimes the rotors don't sit dead centre in the caliper and need to be shimmed to correct this.

[Oldman]

Sometimes the rotors don't sit dead centre in the caliper and need to be shimmed to correct this.

That’s really interesting to hear Les.
For ages my bus had a vibration in the front end that was particularly noticeable under brakes on a long downhill run. I tried machining the rotors….made it a bit better but the problem still remained.
About 6 months ago I decided to buy new rotors and fit them up.
Problem solved!
So based on your comment, it could have been that the old rotors were not sitting exactly centre to the calliper, causing one pad to contact before its pair, exerting offset pressure on the rotor/s causing the vibration…..
Makes sense to me and