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Coach won’t raise to travel height
Spent a week in a campground. Used HWH leveling system to level coach. When I got ready to leave I pushed travel the travel light came on and the low level light went out but the coach didn’t raise. I used the Prevost air valves to raise it and got home but when I flipped the raise tag lever to back in the shop nothing happened. No light no alarm no hiss of escaping air. Do you think this is an HWH problem or Prevost? I just had Nashville fix the leaks and replace the tag air bags. The coach sits level and looks great but I never had this problem before. I live about 50 miles from HWH I’m thinking about starting there unless you guys have a simple wonder cure for this situation.
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27 Replies
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Scott,
This is the opposite of what they say on TV. “You can try this at home”……….most of the time when the coach will not rise to travel height the center solenoid valve coil on the five manifold stack that controls the leveling system has failed.
Set the coach at some uneven position relative to the ground and place the level low controls in the travel position. If it does not move (engine running, bus aired up) switch solenoid valve coils with any other one in the stack BUT VERIFY THE COILS ARE ALL 24 VOLTS.
In the photo the solenoid valve coils can be seen to the far lower right with the multi-colored wires going to them. There is a snap ring at the red caps that holds the coil in place. You need to keep the wires at their respective positions when swapping coils.
Anytime an entire coach will not go to the driving or travel position it is almost always associated with the center coild or valve beneath the coil. If the coach responds by having two of the three leveling corners go to the travel position I would not be focusing on this coil or valve.
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You may have to go one step further if it’s the valve instead of the coil. Here’s what they look like, the valve has the red tip:
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I’m taking it to HWH tomorrow to see if they fix it. I’ve got a valve that’s part of their system leaking so I’m hoping they can fix the whole thing. If not I’ll have to try the things you guys are suggesting. Thanks for all the advice.
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Tom, I think it’s the valve. I called Prevost and they said you need to rebuild these things. How tough is that. I guess you can only buy the entire stack if you want to replace them. Rebuilding seems the way to go.
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Scott,
Prevost will sell the entire manifold with all five valves in place or they have sold the coils or valves independently. The only thing you have to be aware of is the coils could be 12 or 24 volt (it’s printed on the side of the coil) so when buying either the whole assembly or the parts you need to make sure you have the right voltages.
Some converters leave the coils 24 volts and others change them on some if not all the valves.
Easy fix either way.
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Scott,
I’ve never rebuilt the valves, but I think Jon has. I view these the same as relays, I carry a couple spares and when they give me trouble, I just change out the bad one. I’ve had to change out a few on every bus I’ve owned. The middle one for the travel position goes bad more often, they get real hot while the key is on. I still think aux air condensation causes most of the valve problems.
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Joe,
I read your post about the loss of air and leveling issues on the other site and can tell you that you are addressing a couple of issues all at once and before you drive yourself nuts and spend serious money paying for on the job training for a technician it will be best to organize your thoughts and identify the problems and circumstances.
Once you have done that separating the issues and solving the problems becomes much easier.
For example, the loss of air in your primary or braking systems has NOTHING to do with the bus leaning. Further, the total loss of pressure in the aux system can have EVERYTHING to do with your coach leaning, but it might be because it is doing what it is supposed to do. Confused?
Send me an email. jon@prevostcommunity.com
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I recently had a problem with the leveling system not working when the travel switch was turned on. The culprit turned out to be a bendix 75 PSI safety solenoid valve located adjacent to the small air water filter in the lower compartment below the driver side. There was no air going to the rear 5 way leveling valve. We bypassed the safety valve and pressure was restored. The valve was then removed and replaced with a new 75 PSI Bendix valve and we were under way.
This all occured at a service being done at Kevin Erions’ shop. Kevin solved this problem by studying the air schemaics and found the little known valve in the system. The valve is there to protect the main brake system in case of a leveling system air failure. Kevin recently steered his efforts toward Bus repairs. He just completed installing new air bags, new air valves, new batteries, new Magnum Inverter chargers and other items on a list we and he developed to bring our 13 year old coach up to date in those areas. When I heard Kevin was in this business I had no hesitation in leaving our coach with him knowing his reputation of doing excellent work. He performed all items flawlessly for us. He is a great future asset to us all left coast bus owners and those everywhere seeking excellent and reasonable priced work on their coaches. Give Kevin a call @ (714) 342-8588Harry
530-277-5534
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You couldn’t find a better source for coach work than Kevin. Remember, he is the supreme anal one!!!
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That is a protection valve and it is installed by Prevost and provides a tap for the converter from which the converter can connect their accessory air systems.
One thing we have recently discussed on the forum involves checking the air system on our coaches. We have discussed a brake check and we have also discussed system maintenance, especially keeping it dry. Through the coach we have numerous protections and during normal service the technician can help you check the various safety devices by progressively draining the air tanks to verify that preceding tanks still maintain pressure. The loss of air on one tank or system should not cause the loss of air on others.
On my coaches I have periodically checked the function of the protection valve Harry mentioned by dumping air in the steer compartment (I have two places to do this) and making sure the loss of air downstream of the protection valve does not allow either brake system to drop below 75 PSI.
I have never had occasion to check to see if the valve was allowing air flow, but when I have been trouble shooting suspension system problems I do verify I have system pressure downstream from the valve so I know the Norgrens that control the suspension are getting pressure. Good catch Kevin.
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I called John at Jacksonville Prevost and he told me to replace that same valve. I bought one lacally and had it fixed in about an hour. John is very gooding at explaining anything you ask him about.
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Sadly, I am having this very problem today! Went to move the coach to get ready for our road trip and it would not go up to drive height!
Started the coach and waited for it to air up and alarms to go off, the level low alarm stayed on, coach did not go up. I have a printed copy of the level low troubleshooting guide and schematics from this site, so I followed it as well as I could in trying to determine the source of the problem.
Tried to manually raise each of the 3 points with the driver side control switch, it would go up a bit then stop, then I ould hear air leak out (from the circled area in the attached photo).
I was next door to an RV dealer and asked their mechanic to come over to check it out, he opened the water separator tank drain and a lot of water came gushing out, so the air system had water in it. Without checking the solenoids as he didn’t have the time to do it today, he suggested that as a result of water having entered the system, perhaps a valve is stuck or corroded, they can check it out for me next week as they are very busy this weekend.
This is making me crazy!
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Georges
It has been stressed about air system maintenance because of how extensive the damage from moisture can be.
Step one……….get away from the RV dealer. Even if you have to push the bus. You are already in trouble and allowing someone that doesn’t understand the Prevost air system to work on it not only will not assure you of a repair, but will cost you lots of money.
Step two…………if you are not in a position to do the work yourself, take it to someone that knows the Prevost pneumatic system, especially the suspension and conversion portion. You have no choice but to get the system dry and then evaluate what needs to be done to make all systems and devices work as intended. You could be very lucky or you could face some serious expenses.
Everybody else
Please make sure you drain your air tanks (you or your mechanic) every single time you get under the coach. Change your air dryer element routinely. Drain the house or auxiliary system water trap or separator routinely. The benefit to doing this is by keeping moisture out of the pneumatic system is you will not be subjecting all of the working components to damaging moisture.
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Forgot to mention that the leak you circled has nothing to do with the issue with the suspension. It is just a leak. Unless it is blowing so much air you cannot pressurize the aux air system. Which I doubt.
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That looks like a add on iron tee to the system someone put in.?? and that circled opening should be hooked up to something or have a plug in it. Did the rv guy remove something there and not put it back? If not look for a loose plug or a hose that has worked loose with fitting on the end of it. Just from the picture. Bob PS put a plug in it and see what happens. Should not be open.
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