can break pads be replaced without removing the calipers?
Since the rear calipers act as the parking brake calipers, there are adjustment screws that push the pistons out. There are plastic caps on the outside screws, underneath the cap there is an allen screw with a lock nut. On the inside pistons there is a metal allen cap that the screw lives underneath. When you replace the pads, you must back then screws out as you push the pistons out. After installing the new pads, you tighten the adjuster screws until there is .004" clearance between each pad and the rotor. The rear brake calipers are the same as those used on a Porsche 914-6 if you need more information or parts. The pistons in both the front and rear ATE brake calipers used on the 246GT have a step on the surface that presses against the pad. This must be adjusted to the proper 20 degree angle with a gauge so there is proper pressure on the leading and trailing edges of the brake pads. There is a bunch of information on Alfa, Porsche, Volvo, BMW websites regarding how to set the piston position: https://www.alfabb.com/bb/forums/spider-105-115-series-1966-1994/651010-setting-brake-caliper-piston-positions-dummies.html
