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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
Attachment 473
Any comments on changing this procedure to make it easier/better/safer are appreciated.
MM
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.
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.
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.
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
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!;)
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
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
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.
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
Orren, Your are correct and I may have misunderstood your discription. I only know this because I made this mistake on a trailer and paid hell untill I got home and could spend a little time working it out. I only wish I had this info before I replaced the valve and misunderstood the directions.
Thanks again,
Kevin
Mike,
In some respects you are indeed fortunate that your coach uses some 'generic' components. As Freightliner (Mercedes-Benz) , Volvo and other manufacturers exert more of their influence on the HD and bus aftermarket, many items have become 'captive', i.e. available only from the OEM.... thus eliminating pricing competition and aftermarket parts availability, this lack of competition in the aftermarket is bad for everyone.
soapbox mode off - see you guys in the AM
Mango, how did you make out on those air leaks. Does she hold air now?
How about everyone else out there with the used busses. Where are your air pressure guages after 8 hours?
I went out and found 4 leaks today. Three, I was able to stop. Two different air bag inlet fittings, and the belt tensioner valve I fixed.
However
In the steering bay on the ceiling behind the suspension tower, there is a air valve with a plastic electric sensor and its attatched with long small 1/4 in. head screws. Tightening it dramaticly reduced the leak but for fear of overtightening I stopped. Now its JUST BARLY a leak. Ill order one Monday.
So armed with newfound confidence I did an air pressure test. Went from 120 to 40 in 8 hours, both guages going down togeather. BUMMER. That leaky valve is accounting for some of that drop but I suspect I still havent found ALL. The next time I have the engine hatch off I,m gonna check the intake on the compressor, it can leak back through it if it gets wore out or carboned up and dirty. I have scowered this bus 3 times now and am running out of places to look. I can now hear NOTHING ANYWERE[accept for above mentioned] This is an older bus and it does not have a bunch of things to complicate and hinder my attempts so dramaticly. A real lesson in perserverence this one is.
I treasure the morning we wake up to 90 lbs. in the air tanks. MPD or what:o
Hi Joe,
No I still have some, but going to tackle them Friday after Thanksgiving, while Mrs. Mango is doing the Black Friday Spree. Will give you a full report.
Happy Thanksgiving you turkey. ;)
Mike
Hi Mike, I was beginning to think that with four women in your household you worked on the bus so much to get away, but to work when they have all gone shopping???? You must truly be dedicated!!! JIM