How do you make a Prevost XL-40 kneel? Please HELP!

[Scarpace]

Can someone please explain to me the procedure for kneeling a 1993 or similar Prevost XL-40. There?s a switch on the left console (with a picture of a man with a walking cane on it) that works fine to raise the front end up higher than the normal ride height, and then the bus will self adjust back to it?s normal height. But? How do I make the bus kneel DOWN? Sorry if this sounds like a stupid question, but I would like to know the step by step procedure to make the bus kneel. Can someone please explain?

 

[Alaskansnowbirds]

If I remember right it should be a two position switch. Can you "rock" the switch in the other direction. In one position it should raise the coach in the other it should kneel the coach. I used to drive Prevosts for a living but it's been almost 9 years. Is the transmission in neutral? The coach won't kneel if the transmission is in gear. I don't remember if the parking brake has to be set or not. Sorry I can't be of more help. It's been too many years.

 

[Scarpace]

Thanks? The switch does rock in two directions. In its current state, if I rock the switch one way, it is momentary (meaning it has to be held down constantly) and it raises the front end to full height. If I rock the switch the other way (or even just tap it once), it automatically raises the front end to full height (without holding the switch down) and will not stop until I rock the switch again by taping it the other way. So it seems that this rocker switch only raises the front end either way I rock it. Therefore, I am still seeking additional information on how to make the front end kneel. I?ve tried applying the parking brake, holding the brake pedal down, etc?  But I still can?t get it to kneel below normal ride height. Maybe someone else will have some additional information to help me figure this out.

 

[Alaskansnowbirds]

Thanks? The switch does rock in two directions. In its current state, if I rock the switch one way, it is momentary (meaning it has to be held down constantly) and it raises the front end to full height.

That's the way the switch should work.

If I rock the switch the other way (or even just tap it once), it automatically raises the front end to full height (without holding the switch down) and will not stop until I rock the switch again by taping it the other way. So it seems that this rocker switch only raises the front end either way I rock it. Therefore, I am still seeking additional information on how to make the front end kneel. I?ve tried applying the parking brake, holding the brake pedal down, etc?  But I still can?t get it to kneel below normal ride height. Maybe someone else will have some additional information to help me figure this out.

That is not how it should work. When you rock it in the direction where it stays in that position, that should be the kneel position. It should stay kneeled until you put the switch in the center position or put the coach in gear. I'm wondering if you have a bad switch or a miss-wired switch. Has it ever worked properly since you have owned the coach?

 

[Scarpace]

I'm wondering if you have a bad switch or a miss-wired switch. Has it ever worked properly since you have owned the coach?

I have owned the coach for a few months now and I am currently restoring and converting the coach to fit my needs. I thought it seemed rather odd that the switch would raise the front end either way I pressed it. It would sort of make since to me that maybe something is hooked up backwards or something in regards to when I press the switch and it just keeps sending air to raise the front end (until I stop it by rocking the switch momentarily the other direction). Maybe when I press the switch in that direction, it's suppose to keep letting all the air out of the front bags instead of continuously adding air? Hmmmph. Now what? I guess I can try to make since of the wiring diagrams available from Prevost, but maybe there?s a way to test it out or rewire it somehow. Please help. THANKS FOR YOUR HELP SO FAR!!!

 

[Scarpace]

DIAGNOSTIC UPDATE: According to Prevost, they have informed me that one or more of the kneeling valves located under the frontend has most likely failed. This is apparently a common issue that can be caused by dirty (bad filtered) air over time and can affect any and all air valves at any time. They explained how an internal reset spring within the valve can become stuck and that by replacing the valve should correct my kneeling issue.

 

[ava]

thanks for the update, I just wanted to add that once you get it
fixed, if its in the kneel position and you forget, it won't go into gear,
hehe, ask me how I know ;D