Brake caliper preventive maintenance rebuild?

Although that pic is correct for a floating caliper with slider pins, Tacomas use a fixed caliper so there are no slider pins. The only pins on our front calipers are the ones that the brake pads are located with. And one has to be careful with lubricant on them because applying too much can lead to it getting on the friction material on the pads - which we all know is bad. I just install new pins on mine each time I do the brakes.

 

I was planning on just replacing the pads and rotors and when I pulled off the tire to change the pads, I noticed a small tear in the boot on the caliper (both the L and R caliper, inner side). While the calipers worked fine, I decided to delay changing the pads/rotors until I installed new calipers - the plan being to take the opportunity to rebuild my original calipers and keep them as spares. The calipers were original (10 years old) and had 200K KM on them.

I replaced the calipers/pads/rotors a few weeks ago. I was surprised when I got around to having a closer look at them this weekend, that it appears that on each caliper, the seals had gone on the pistons closest to the engine. As a result, the 'cup' of the piston was heavily rusted. The 'clean' side of the piston was in decent shape, but the area that came in contact with the outmost edge of the inner caliper cylinders did show some marks from corrosion. I was able to clean up the caliper and remove the pistons with compressed air - nothing was seized. But I was surprised that the seal on each of the four inner pistons had gone and that the outside piston seals were in decent shape. Truck was 10 years old with 200K KM. I change the brake fluid every 3 years. Plan on buying a few new pistons and rebuilding over the winter.

So to answer the question I posed as post #1 on this tread, there may have been benefit of doing some 'maintenance' on the calipers before the 10 year / 200KM mark. In hind sight, would have been a good idea to take a closer look at those caliper seals a few brake changes ago.....or get into replacing the seals every [x] year, whether they need it or not. Looking at my calipers, I would assume that my inner seals have been bad for a few years, so maybe replace those seals every 5 to 7 years, to try and lengthen the life of the caliper.

A few pics below. I am assuming that the failure of the seals led to the rusting of the pistons.

Showing pistons/seals on side of caliper closest to the engine. Both the left and right caliper had seal failures on the engine side of the caliper:



Pistons / seals on the side of the caliper on the 'outside', furthest away from the engine. Both the left and right caliper look very similar and the pistons on this side of the caliper was fairly 'clean'.



Top view of caliper. You can see that pistons/seals on the inside of the caliper (engine side) were in worse shape than the outside. Both left and right caliper looked similar, with the inner pistons looking a lot rougher than the outer pistons.