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How to find the correct height, after replacing suspension leveling valve 09 prostar. also I want to replace the cab leveling valve. I am going to install pro air ride for the cab, also my rear valve is leaking or hissing air.

(10-10-2016 )rgreen Wrote: [ -> ]How to find the correct height, after replacing suspension leveling valve 09 prostar. also I want to replace the cab leveling valve. I am going to install pro air ride for the cab, also my rear valve is leaking or hissing air.

For 22.5" low-pro tires -- Rear leveling valve...
Place a board across the back tires from one side to the other while parked on a fairly level surface. The bottom of the board should be about 1/4" - 1/2" above the frame. I.E - If a trailer were to drop off the fifth wheel onto the frame,.. It will hit the tires first and have to go another 1/4" - 1/2" to hit the frame.

Cab height....
Adjust the back so that the bottom of the cab is even from front to back as compared to the frame rail.

I think this is dependant on tire size, 22.5 and 24.5 have to be different measurements.

(10-10-2016 )8042 Wrote: [ -> ]I think this is dependant on tire size, 22.5 and 24.5 have to be different measurements.

Thanks for the correction. Not sure about the 24.5" height.

(10-11-2016 )Rawze Wrote: [ -> ]

(10-10-2016 )8042 Wrote: [ -> ]I think this is dependant on tire size, 22.5 and 24.5 have to be different measurements.

Thanks for the correction. Not sure about the 24.5" height.

Thank you I am running 22.5 does it matter what side board like a 2x4

Measure your fifth wheel height. 47 1/2" and you should be on the money.
The formula for Pete is tire height ÷ 2 + 8.75" to bottom of rail for 4 leaf for 22.5
Make sure the rod length is correct and seated in the rubber fittings so they don't flex under load..
Check the range when it dumps or builds air. It's a close range, maybe 2 inches of travel on the leveler arm.
Valve should cut off air at correct height and start filling when it drops below, just remember there is a lag time.


I beat my head against a wall trying to find the source of a driveline vibration only to discover it was incorrect rod lenght on the valve that was installed by someone I thought knew what they were doing.

Doing this fix now. Thanks for the measurements.

(09-07-2019 )74bassman Wrote: [ -> ]Doing this fix now. Thanks for the measurements.

After you set ride height check the distance from middle of the drive tire to the frame. All four should be same +- 1/8 inch. If axles offset readjust ride height.
And check driveline and pinion angle by specification.
Front suspension leafs and tires can screw you up really bad.

Maybe i'm thinking of something different but isn't their a linkage with holes and that is what you adjust it with on some models?

Are you able to match the position of the old one to new one?

I replaced one on my truck and it just bolted on.