Steer Axle Height Control Valve Early ZF Suspension - Printable Version
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RE: Steer Axle Height Control Valve Early ZF Suspension - jdkskyking - 01-07-2025
Shoot holes in this !
RE: Steer Axle Height Control Valve Early ZF Suspension - jdkskyking - 03-01-2025
Finally had some time off and some nice weather in Northwest Arkansas so I decided to cause some sway bar arm envy…
RE: Steer Axle Height Control Valve Early ZF Suspension - cwl1979 - 03-01-2025
Is that going to be the new mount for your leveling rod? If so thats very nice and well built should work out nicely. If not... what's it for?
RE: Steer Axle Height Control Valve Early ZF Suspension - jdkskyking - 03-01-2025
Yes. I’m going to replace the current HCV with a new one. The new HCV will have a longer arm.
My goal is to achieve +-50° of HCV arm angle to mainly improve the exhaust rate of the valve and hopefully stop the front of the bus from having more air in the bags and negatively impacting the steering alignment.
It’s entirely possible the current HCV was damaged when the tech welded the arm to the valve. Simply replacing the valve might solve the problem.
Nonetheless, I believe that a combination of a longer sway bar arm will improve the functionality.
Today I measured the total throw of the sway arm from full down to max up, it only moves 2 1/6” at the center of the mounting bolt.
Ultimately I’d like to relocate the HCV to the left steer axle and set it up similar to the drive axle HCVs.
I guess you can say I’m experimenting.
RE: Steer Axle Height Control Valve Early ZF Suspension - cwl1979 - 03-01-2025
Very nice. Let us know how it works out. I know I've contemplated running dual HCVs on the front axle but... I'd better wait till in down in the states. It made it to Alaska like it is.
RE: Steer Axle Height Control Valve Early ZF Suspension - Richard - 03-02-2025
Talk with the engineer at Dayton Air Products. You want an HCV with the smallest deadband possible, that would be the area around zero position that did not result in air flow either direction. When you do that, you also need slow response so the valve actuation doesn’t consume a ton of air with each bump in the road.
If you put a longer arm on the HCV, you will negate the benefit of the longer arm on the sway bar. The HCV works off degrees of rotation. A three inch bar on the CV and a three inch bar on the sway will give exactly the same degrees of rotation as a six inch bar on the HCV and a six inch bar on the sway bar. Now, if you leave the 3 inch bar on the HCV, and use six inch mount distance on the sway bar, you will double the degrees of rotation at the HCV.
RE: Steer Axle Height Control Valve Early ZF Suspension - jdkskyking - 03-02-2025
RE: Steer Axle Height Control Valve Early ZF Suspension - jdkskyking - 03-02-2025
I believe I’ve discovered the smoking gun.
Today I was finishing up the new sway bar arm by powder coating it before I installed it.
In preparation to install the arm, I put the bus in travel height, pinned the HCV in the neutral position and disconnected the control rod.
I had to go to work for a while today so I was away from the bus from 2pm until about 6:45 pm.
When I went out to check on the bus, the steer air bags were at maximum inflation! It looked higher than I’ve ever seen it but it might be because I didn’t expect it to be that high.
My assumption is the HCV is faulty and is passing air to the bags in the neutral position. I can only assume that this is my true problem with the steer axle travel height increasing as I drive and causing the alignment to drive poorly.
I’m sure the mods I’m making will improve my situation but it is nice to know that I’ve found a smoking gun…
Moral of the story… don’t let a tech weld your HCV arm to the valve shaft….
It’s always something….