Brake Disc Replacement: How-to Guide (312mm)

Hello,

So far, I haven't found a precise answer to my problem anywhere.

Due to severe rust, I want to replace the front brake calipers on my BUK-Ibi. It originally came with the large 312mm brake system with the standard floating calipers, which, if I recall correctly, are attached with Allen screws (with those plastic protective caps around them).

My question: Does removing the seat lower the bike's center of gravity, or is it also necessary to loosen the brake caliper bracket from the axle?
In the latter case, I'm reaching the limits of what's possible with my garage setup, because even with the old ALH Ibiza and its 255 mm system, I had to use all the extensions and tricks I could think of to maximize the working space that a small, 2-ton DIY jack provides .

The front needs to be completely removed, but the back is okay as is.

Okay, then I'll check again to see if I can complete the task on a stage in our village workshop .