I’ve tested the following and permutations of between categories:
1. Without and without RABs
2. Vacuum vs Hydro
3. F250/F350, F-Super, & Red Head Steering Gears
4. Various OEM, Rebuilt & New F350/F350 pumps, F-Super Third Party Pump
= Braking w/ Vacuum =
Braking with vacuum and rabs was mediocre. Switching the rabs to the f super bypass and vacuum assist was good. Did brake testing and feel between a 2018 Mazda CX-5 right off the lot and F350 f super rabs delete w/ vacuum and the truck had both better braking and feel than the Mazda. The CX-5 of that year atleast just doesn’t feel right, like it’s a CX-3 sedan chassis with a small SUV body ontop. Regardless, this is a good combination if you like vacuum.
= Braking w/ Hydro =
The first thing about hydro is that your steering and braking is now “connected” and you will notice to varying degrees based on a few of my comments coming up. Regardless of pump, factory f supers had hydro and rabs delete. They “expect” to be loaded in the rear. Most had heavy commercial bodies during sale. Hydro on a 250/350 with f super rabs delete locks the rear wheels easier than vacuum.
F350 Pump w/ F Super Res - Worse than the vacuum w/ rabs delete. Hydro has a spongier feel in general but you can tell they wouldn’t roll off the lot like this. It is to most people “good enough” and depends on where your good enough bar is. At idle and in parking lots you can really tell the steering and brakes are part of the same system. As you are moving around at idle speeds the wheel will intermittently “catch” a second turning and braking at the same time or slug for a split second. Panic braking can pulse/shake like it’s a bad rotor but it’s not.
Early on I found what I’m describing above hard to believe, I tried (3) different f350 power steering pumps. OEM, rebuilt, new. All the same characteristics. If I learn that the f350 and f super are the same, than there is a quality control problem. I’m relatively certain that atleast the spring and believe valve are different.
F-Super Pump w/ Hydro
After the above, I looked up the EDD pump that the F450 and F550 powerstrokes would use. Came back with the 6014R. Swapped to this pump. Night and day. Any of the negative characteristics above are gone. You can still tell it’s hydro and connected to steering but smooth to a point where you can forget it’s part of the steering system.
= Steering Boxes =
Rag joint vs borg u joint shaft and rag delete - rag delete all day
F250/F350 boxes - sloppy. f super rebuilt box - sloppy. Red Head Box - good.
factory gear with rag joint -
https://media.tenor.com/sv0yh8rkqagAAAAC/ride-fozzie-bear.gif
Summary Optimal Combination:
Rag joint delete, red head box, f super pump, hydro, f super rabs bypass
Runner up:
All the same above except vacuum if you don’t mind the pump accessory
