Front brake caliper pins

[DarkSkyGhost]

I have a 2003 Yaris phase 1, french build (SCP10L-CHMNKW 01/2001-01/2003 SCP10 LUNA FRP LHD 1SZFE MTM 5F 5D). 170k km. Front disk brake supports are made by Bosch (I think - it has Bosch written on caps for pins).

The brake pedal goes a long way to the floor until the brake pads engage. The brake pads do not engage the brake disc fully - only half of the pad is making the contact with disc - the inner circle on the brake disc (about 40%) is covered with rust.

I've changed brake fluid recently, there is no air in the system. New front brake discs and pads, new rare drum shoes. Mechanic in the shop checked rare drum brakes, they are fine. He also checked for the air in the system. None.

He showed me that brake caliper assembly, where brake piston is seated, is pretty loose. That is, when brakes are applied, and piston engages the pads, the caliper assembly moves inwards, and the force is not equally applied on brake pads. He believes that is the reason for long brake pedal travel.

We've looked at the pins which slide into the caliper and hold it in support and noticed that they are moving from side to side, making whole brake caliper assembly move from side to side. The pins are 47715A No. 1 and No. 2. Notice that they are different.

He suggested me buying new ones and checking if they make a difference. I bought these ones, but they didn't fit. Goes only halfway on the top, and doesn't go into the hole at all on the bottom. Oh well.

Out of misery I thought switching the old pins around - I've put the pin 47715 No.1 from the top (it has no gummy part 47769) to the bottom, and the pin 47715 No.2 from the bottom (has 47769, and pin itself is a bit thinner than No.1) to the top. The pins were seated nicely and not moving from side to side. Tested out - lo and behold, brake pedal travel changed drastically, brakes engage almost instantly. Brake caliper has almost no play. Me happy.

My questions are:

Is this switcheroo safe? Am I going to damage brake caliper like that? I'm guessing the gummy part 47769 is for keeping out the dirt and keeping the pin in place. But why is there a play when these pins are in the original location? Why the pins are different? Can it be that those pins have made the holes bigger from brake usage? Or should buy replacement and see if there is any play with new ones in the original location (I'd prefer not buying them, would save a bit of money)?

Also, is it save to drive without shim kits (part. no 04945-20210) and fitting kits (part no. 04947-0D010) on the pads? Got the car without these parts installed.

I would appreciate any input!