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air ride system problems
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Are the others 12 or 24.
Liberty is the only converter I know that uses 12V coils and then only on their Classic model. And not on the center coil which is the ride height control coil.
Just to make sure I understand when you have the key off and crack the nut on the compression fitting no air should come out, but with the engine running cracking the compression fitting has air coming out?
That is who it should be because that is shifting all 3 5 ort Norgren valves to the ride or road position.
If you have ruled out a bad solenoid valve on the manifold the next step is to verify the ride height valves are adjusted correctly. Manually set the coach at the ride height which is approximately 11 inches from bay doors to the ground. Then look to see each ride height valve arm is centered and level. If the arm is perpendicular to the valve body, not up or down I think you can rule that out. I believe you can see each, but be careful, do not get under the coach unless you have it supported at the chassis support points.
If the valves are adjusted OK then it starts getting more complex.
Please just verify it does nothing when you have the coach up or down and the go to the road or ride height. I say that because if it moves toward the ride height it could be a ride height valve arm adjustment, or if that is not it, the coil is good you might be dealing with a hydraulic lock due to moisture or sludge in the 5 port valves. That is the next step to check.
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engine running I get a very small amount of air coming out of coil 3 supply line to a valve just left of the 5 coil bank and nothing when the motor is off so it appears to be working. When I attach the coil 3 line back to the valve the front will raise and nothing out back. I got a look at all three leveling valves and the arms are straight out not on a angle. The rear 2 are new front is not.
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When you have full accessory ir pressure, key on, level low set to the road or ride position you should have a lot of air flow coming through the middle solenoid valve.
That air is “signal” air and it goes to the actuator on one end of the 5 port norgrens that have an internal spool that shifts when pressure is applied. If you lack air flow the valves will not shift and the ride height valves will not supply air flow to air bags, or will not exhaust air from them because the norgren valve is not shifting. The ride height valves get their air supply directly from the accessory tank, but the signal to the norgrens comes through the manifold. If your manifold is getting and passing air to the norgrens then you have to verify air is getting to the actuators on the end of the norgrens and if it is, the valve is not working,
They are repairable but often the new ones just make more sense, but at over $100 apiece you need to open them up or at the very least bench test them
The end actuators are numbered, like 12 or 14, and when air is supplied to them it opens the path to the corresponding numbers, like if you put air to 12, there will be an open air path between 1 and 2.
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The middle #3 coil is always a 24v coil from everything I’ve read for your year model Prevost. Maybe Art Waddle will chime in here soon since he has a 97 Royale and is a DIYer.
Here is what each of my 5 stack coils do:
12v #1 coil is for supply
12v #2 coil is for manually raising & lowering front
24v #3 coil is for the normal D”drive” mode
12v #4 coil is for manually raising and lowering the back right
12v #5 coil is for manually raising and lowering the back left
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Thank you for all this great info! could i use shop air to test the see if more air would engage the rear valves?
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If you haven’t swapped coils I would think that would be easier, but if you have and no change then see if holding shop air on the air line out of the 3rd valve does allow the coach to go to ride height.
But if it does not and since you ruled out arm adjustment you are getting to the point where you need to start verifying the 5 port norgrens are shifting. Moisture, or sludge created by the presence of moisture in the norgrens will really mess up how a coach responds to level low commands.
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Don
Thx for posting that bulletin. I’ve been told that existed, even Prevo had a difficult time finding it and what they sent me was similar but for an H.
I have a 95 chassis XL40 with the old tag logic. It will dump tag when AUX drops to about 20 psi. My VIN is S1001572 which (is close) but according to bulletin doesn’t (or shouldn’t) apply to XL40 MTH shell, only XL45.
Has this been done on your Liberty? Or maybe it is newer tag-logic setup. If it was changed did you do it yourself and pretty straightforward?
Thx BG
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This may be breaking a sin because I really hate to see re-engineered coaches (by owners), but I think if you do not want to lift the tag axle ever, put a plug in the two 3 port valves between the tag and drive axles. That way when the old logic shifts the valve, air cannot escape. You can stilll use level low to lower or raise the coach.
The only reason I say that is because the change was about $1800 20 years ago and is likely a lot more now. Even if you do it yourself it isn’t cheap,
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Crafty, Jon, to whom all it may concern.
I just got off the phone with Art. He told me his 97 Royale “5 stack” is just like my 96 Liberty “Classic”. All 12v coils except for #3 which is 24v.Art’s busy at the moment and will chime in later. -
I tried the shop air thing with no luck in the rear coming up just the front Jon. Looks like it could be the norgens out back. Can i get to them if I pull the tag wheel?
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On your coach they are behind the rubber fender liner in front of the drive axle. I always pulled the outer drive wheel.
Don’t get under your coach unless it is supported. Especially because you are working on the suspension. Raise it, support it, dump all air from the air bags just to verify it is supported.
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I just pulled each coil and they all look the same and have 12 on the side of the body. I does have enough air to shift the front norgen valve in drive mode to raise the coach.
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No, the 3 port/2 way Norgrens are on the inside of the frame above the tag axle.
The 5 port/3way Norgrens are on the the bulkhead, forward of the drive axle.The bus will need to be raised and supported properly at the jack points.Safety first. -
agreed 100% on safety so the wheels stay on lol not one bit crazy about jacking this beast up but i do have heavy duty stands so we will see. Im trying to finish cutting and buffing the paint right now
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Just a thought, does your coach have a converted added auto level? If so, and if it is on, you might just be in a tug-a-war between the Prevost level low and the converter auto level. On our 97 CC the auto level activates the same solenoids used by the level low system so if one is on and one is off it can do unexpected things. If auto level is on it over rides the auto ride height settings.
Jerry
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