Hard pedal

Darthomas
Unless the bellows is perforated, corrosion inside the caliper is from inside the caliper.
IMO;It is very nearly impossible for moisture to enter the caliper's pressure chamber, from an external source.

IMO The KH design never had a problem. The problem was the equipment of-the-day,required to machine the rotors in the field. It had a really hard time maintaining parallelism.
And yes, the pistons did stick from time to time. But that was moisture related. So how did the moisture get into the caliper? I will always maintain that somebody; let it get in there, or put it in there.
Why would I say that?
Two reasons. 1) brake fluids of the day, and their containers, and the careless attitudes of persons servicing those systems, all conspired to allow moisture to enter from the M/C, and 2) lack of knowledge.
On what basis?
One reason; I put Silicon fluid into my virgin system in 1999. It's still in there.The M/C has a sealed bellows. My KHers still work perfectly.
Oh, and I machined the rotors myself, on ancient machinery.

I like the fixed caliper system. There are no caliper ways to require periodic repairs, and there are no slider pins to seize,or bend, and pads are a drop in deal.
Fixed calipers are simple. No moving parts.They spread the clamp load over a very generous portion of the rotor. The large pad size lasts a long time.
What's not to like? IMO, on a streeter, this is a winning recipe.

Please note the extensive useage of IMO. I would have typed IME;E for Experience, but I have only worked on brakes for maybe 20 years.And I didn't work on brakes every day.I was a general mechanic, and not a specialist. Some fellows here have much more experience. So the punch-line is this; I have had very good success with KHers; your results may vary.