KH Discs vs 73+ Discs

A quick word about caliper/piston maintenance.
It is well known that the non-dot5 fluids are hygroscopic. The moisture they absorb gravitates to the lowest point in the system.The caliper bores can rust and the iron oxide would occupy the very valuable space between the piston and the bore.Furthermore moisture can enter from the atmospheric side and accumulate in the O-ring bore.When oxydation piles up there, the room in the groove diminishes and/or the seal swells up. This puts a lot of friction on the pistons and eventually seal-retraction no longer works and the pads remain in closer contact with the rotors, eventually glazing up and or wearing out the rotors prematurely.This can/will happen in any brake system with non Dot5 fluid. Its worse in aluminum bodied calipers.

Now the KH having 4 tight fitting pistons, are or have been. somewhat susceptible in the past,to sticking due to this phenomenon.The absolute best thing you can do for your KH system is to use the silicon brakefluid and to grease your sq. section O-rings and their grooves with a silicon grease. Problem solved. I also run my wheel bearings on the looser side of spec, to aid in piston knock-back, and I dont use any anti-rattle springs.When I hear the pads rattling, I know the system is free-running.I believe my success with these KH tips speak for themselves.

As an aside, when I slip my 4-speed into neutral at 60 mph, the car coasts what seems like forever.It coasts better/further than any car I have ever owned.Whats the big deal about that you ask? Rolling resistance. The less of it you have, the less your engine has to work to overcome it;ergo, the less fuel you have to burn to either accelerate the mass, or maintain it at a cruise speed.
To that end, I can tell you that its easily possible to get a 68 cuda360MT into the 30mpgUSg, and still go 12.9/106.

Now, a word about the single piston calipers. These pistons are much looser fitting in the bores, and survive a long time with sludge in them. One of the consequences of their looseness,is that they can "****" in their bores. This can allow more pressure to be applied to the rear/trailing edge of the pads, and they wear at an angle. The same thing can happen if the pins are not straight, or the caliper-ways are not at the proper angle.The point is the pads may need to be replaced more often than necessary.When the pads are replaced, the pistons have to be pushed back into the bores, plowing through the accumulated rust/sludge.And this is when trouble can start. So again, the silicon can come to the rescue. Then theres the slider ways which have to absorb all the brake force and send it into the chassis. They also like to rust up, and/or wear out.
All-in-all, I just prefer the zero-maintenance of a fixed caliper. And the KH is a fine example.
Just my 2cents