It's raining, so I decided to bite the proverbial bullet and change the ST13's front brake pads. I'd done the rear ones nearly 30,000 kays ago (just shows how much more I use the rear than the front, bearing in mind the front does 70% of the stopping effort). The rears are pretty easy, and I did them without removing the caliper. There are "how to's" for that elsewhere (also for the front, but I want to tell my story).
There was no way I could push the pistons back, try as I might, so I looked at what removing the calipers involved. Two bolts- not rocket science, but the disclaimer on the pad's packing says "Do not attempt to fit this product if you are not a fully qualified mechanic". Well I'm over qualified, being a bush lawyer as well as a bush mechanic, so let's stop wasting time...
Before committing to the enterprise, you'll need to have a long handled (for leverage) 6 mm Allen key, and an 8 and 12 mm socket or spanner.
I did the right side first. I pulled the 8 mm bolt to drop the pads. They were at 1.5 mm, just below the recommended 2 mm, so I wasn't getting in early on this job!
Removing the two caliper bolts is easy, then with due care for the flexible hoses, I turned the calliper and checked the pistons for corrosion and deposits.
Top article here on cleaning pistons:
http://www.st-owners.com/forums/showthread.php?101206-ST1300-Rear-Brake-Piston-CleaningThen I used the socket spanner handle to ease the pistons back flush with the caliper and installed the new pads. The inside one was very reluctant to seat, but I won the battle. As is always the case, I lost the next battle. There was no way in creation the pads were going to fit over the disk. I have the "Metal Gear" pads and they have a 1.5 mm plastic packing under the perforated backing plate. The originals don't have that, so I figured the packing must be for another type of caliper and removed it. The pads would then fit over the disk. If anyone knows better about this feel free to contribute.
It takes two full strokes of the brake lever to reset the pads. I think it wise to do it to the first side before removing the other side or you might overflow the reservoir.
Reassembly from there was easy. The left hand side is mounted differently, using the Allen key type bolts.
Luckily the rainy day came when it did, otherwise I might have done what I did to my poor ST11 when the pads wore down to metal. I'm sure that accelerated the disk wear to the point they needed replacing at 130,000 kays.