I have had the same issue and decided just to take the car to AWD in perth today.
Both my front Calipers were sticking on my 98 WR Sport....the brake pedal felt like standing on a wet sponge so just bit the bullet and got both the front 4 pots change for fully recon ones with new disc/pads. Offside front lower piston was rock solid, certainly explains the worrying stopping distances..
AWD had the bit's in stock so wasn't too much hassle. around £130 each inc Vat.
They had to replace the rear bumper beam as well. That was a nightmare as it came off in two pieces in the end
rusted right through !!!!!