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Ride height adjustment
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Jerry,
The XLII’s are 12″ from bottom of the top plate to the top of the bottom plate.
The rear is 11 3/4″. Not sure if the H is different.
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Guess I should measure the distance before I take the valve off, and go back with it there. The valve in question blows bubbles out of the exhaust tube, and I’m hoping that’s the cause of my leans.
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Jerry, don’t make it more complicated than it needs to be.
If the new ride height valve arm and hole location is the same as the old one, and you do not change the length of the rod it is a drop in replacement, no adjustment required.
The Prevost spec for height is as measured between the top and bottom air bag plates, but if the coach is sitting on a flat floor I have been able to use the measurement between the floor and the bottom of the bay doors. Just remember that there are going to be variations due to the small angular operating differential of the valve, so if you do have to make an adjustment try to take a variety of measurements such as starting out with the bus low, the bus high, the bus leaning, etc. and you will note minor vairations in where the bus ends up when you rest the switch to the driving height position. The object is to get the average as close as you can get because it will not every go to the precise height every single time.
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when not jacked up???
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Good point Bob.
NEVER EVER DO WORK ON A PREVOST SUSPENSION UNLESS THE CHASSIS IS SUPPORTED AT THE CHASSIS SUPPORT POINTS.
Having said that, if the key is off it is unlikely the coach will drop if the ride height valves are removed because the 5 port Norgren is holding air in the air bags. But it is not worth the risk to be monkeying around beneath the coach to not support it.
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bad valve or bag to full=needs to lower coach to set ride height. Exhaust air from bag to do this—- as Jon said safety first key on position… more details on when you observed bubbles.
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OK, got it on not making it complicated. The valves are easily accessible without getting under the bus, with the fenders off, it is exposed, I can stand up and replace them. I’ll just release the air first.
Jon, is there just one ride height valve per side on the back? I don’t readily see one for the tag axle.
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Yes, There is one ride height valve in the front, top center over the axle and one on each side in the rear, just ahead of the drive axle. The three air bags per side in the rear are tied together as far as pressure goes unless you lift the tag axle, in which case the path between the two drive axle air supplies and the tag axle air supply is blocked by the three port Norgren.
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Got it, thanks
Just went and bought more DOT compression fittings to replace push locks as I go. They are expensive!
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DOT fittings are not cheap, but unlike the push in fittings that become a source of leaks, a never leaking compression fitting is priceless.
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I am totaly convinced of that after seeing all the push-in fittings leaking.
We use plastic push-lock fittings in Drag racing, they operate air powered parachute launchers, air shifters, solenoids, etc. They are used because of light weight, and quickly disconnected when working. Some even use air operated shocks. When the air bottle is empty, we just put another one in.
NOT the case with Buses, I’ve learned that very quickly………….
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I’m on the same page, change them out to DOT compression, but I have several DOT push in fittings in the steering bay on my 3 ports that I have had on and off numerous times and they don’t leak. They’re black plastic and leak free.
Ya I know, I’m just lucky….
Jerry – You think those fittings are expensive, just buy a few of the 5/8 DOT compression for the air bags and you’ll feel the pain!:)
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Tom, I bet those are close to $50 bucks each.
Jon, Got the ride height valve changed a few minutes ago. Once I took it off, I saw how it is adjusted. Just by rotating the valve in the slot on the bottom hole on the mounting bracket.
The bags on mine measured 11 3/4″ on pass side and 12′ on driver side, that’s from bottom plate to top plate on bags, inside measurement. But the bus measured exactly the same from bottom rail below bay door on each side, 12 1/2 “.
Which Norgrens if bad would contribute to the bus leaning? The 5 port, 3 port or what? (in case the ride height valve wasn’t it)
The more leaks I fix, the more I find leaking………….
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Jerry, regarding leaking in the suspension systems I cannot say where a leak might be, and on an older coach with original equipment it is unlikely to be a single leak, but a combination of minor leaks that have begun due to age. The air bags themselves can leak, all Norgren valves can leak in ways you will go crazy trying to detect (ask Tom), and fittings, especially push in can also leak. I have had compression fittings that were undisturbed leak due to a crack in the fitting, I have had air bags leak at the bottom of the can, and I have had Norgren valves leak not only through the valve, but out the ends of the valve leaking past the spool.
The good news is if you are prepared to do your own work for about $2000 for parts you can totaly renew your suspension and if you are careful and all your fittings are leak free you will end up with a coach that is good for years. But as others will tell you attention to detail is critical and if it leans when you get it done you spend a lot of time following air flow to chase down the leaky point.
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Glad your doing the air work yourself. not to bash Prevost but they had mine in several times and replaced 2 way,3 way, 5 port, , bags and fittings and it still drops after a day or two. Front has stayed up over 5 days but back will hit the carpet one side at a time over a day or two. When I get evrything togother gonna try myself and see. Good Luck.
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