Replacing Ride Height Valve

[MangoMike]

A close cousin to the Norgren Valve, this dude is not above leaking either.
Here's the HOW TO:

http://www.prevoman.com/Pages/Ride%20Height%20Valve/RHVpg1.html

valve_3011.jpg

Any comments on changing this procedure to make it easier/better/safer are appreciated.

MM

[Joe Cannarozzi]

Unless you have a LIberty and a light to remove for access youll have to pull the duals and remove the rubber flap material forward of the duals that is there to protect this area. There is 1 on each side on the rear and 1 centered at the stear axle.
Good job Mike.

[win42]

Mango: did you check to see if the newer quicker acting valve would work on our older buses? It could help to prevent the leans on long curves.

[Jon Wehrenberg]

Joe, removing the wheels makes access a lot easier, but with the coach all the way up on the air bags (and securely blocked) it is possible to do the replacement with the wheels on.

Harry, I'd question whether it would be wise to start messing with the length of the time delay. I am sure Prevost did a lot of testing to find a delay that would work under most conditions. I can envision the wrong delay, or different delays on each side causing an out of sync leaning of the coach that at best will give the riders nausea, and at worst a lean in the wrong direction affecting the coach stability.

On long curves the bus should hold the proper attitude regardless of the delay, but on the shorter curves I can imagine that just about the time the valve reacts, the coach comes out of the curve or enters another in the opposite direction, at which point the coach is now leaning the wrong way.

[MangoMike]

Harry,

We'll have to check, but as I recall the new valve system is tied into a ride height computer of sorts. Would be interesting to hear the details.

MM

[truk4u]

Mango - Nice job....

Harry - My Country Coach had the quick action valves and I hated it. CC likes them because they make the plastic coaches respond quicker to side to side loads. The down side is, they use to much air while driving down the road from all the little movements. I hooked up a gauge to the aux tank and while driving, I could watch the aux pressure deplete. My compressor cycled every 1 to 2 minutes. I added an additional aux tank for more capaciity and that helped. I couldn't change out the valves to the slower response because all the plumbing and mounting brackets were different. CC even admitted they may look at going back to the slower valves, but I'm sure that never went anywhere.

What is the life cycle of the compressor and dryer? Who knows, but I thought it could lead to premature failures. And they call Jon anal! Prevost has the right setup!

[Orren Zook]

MM,

In the header for this thread you mention 'right' height control valve, did you mean 'correct' or right/curb side of the bus? Either way, the valve you have pictured here and on your web page are universal in that it can fit either the right (curb) or left (road) side. The center port is always the inlet/supply, the top port is always the exhaust and the bottom port is the delivery port. This valve has been used by Neway and other heavy duty air suspension manufacturers for years and is readily available throughout the US and Canada. If the valve is centered when installed via the little dowel supplied you should always be able to level without changing the adjustment nut.

On the Spartan chassis with IFS the alignment of the front end is controlled by the vehicle ride height - maybe on the Prevost too, but I don't know.

Here's a link to explain some of the alignment terms (caster,camber,toe in/out): http://www.ozebiz.com.au/racetech/theory/align.html

[Kevin Erion]

Orren,
Please be careful when you say that the top and bottom ports are always the same, I don't think this is true. Depending on which direction the valve faces you have to change the air lines. The instructions are a little misleading and Mango did the correct thing when he said I just put the lines back the way I removed them from the old valve. Had he reinstalled them according to the valve instructions he would have a bus that leaned due to the valve, not from air leaks.
Kevin

[Orren Zook]

Kevin,

I didn't say that the ports are the same, what I said (or meant to say) was that depending on how this valve is mounted the top port will always be the exhaust port and the bottom will be delivery port. This design allows the same valve to be used on either side (curb/road) of an air suspension. Prior to Neway's introducing this style of leveling valve in the 1970's their valve application was dependent on side of the vehicle where it was mounted. The introduction of this universal style allows one valve to be universal for their leveling valve applications. Great for fleets and HD parts houses - only one number to stock.

[MangoMike]

Orren,

You're right it should read RIDE Height Valve, as I posted late at night and mistyped. Good call.

The Valve is designed to be universal for either side and the EXHAUST has to be the top port. The more I look at the directions I think they were showing a Driver side installation and I was doing the passenger side.

Glad you and Kevin are paying attention.

Mike