Why is the brake caliper stuck?
The possibility of entrapment increases significantly even if the brake fluid is not changed in time: because it is hygroscopic, the moisture content of the brake fluid increases over time, which also causes corrosion of the pistons and cylinders.
Using the wrong brake fluid. If it is too viscous, the piston does not return to its original position after braking. In addition, pistons made of polymeric or composite materials may increase after contact with an improperly selected means.
Change the brake fluid in time. It is hygroscopic, so the amount of moisture in it increases over time. This not only affects the braking efficiency but also causes internal piston corrosion.