[Archived]

Your system is a bit different than mine but since you are leaning to the right, I suspect your right REAR 5 port Norgren is misbehaving allowing air to escape through the exhaust port.

Seems like there is more than one thing going on since when you plug the exhaust port, the front goes down. That would imply a leak at the air bags or associated valves.

Jon will be along any moment and tell us what is really going on.

Gerald

[Archived]

There is no 5 way in the rear. Only 3 way, 4 of them and they are brand new.

The front goes down if i leave levellow switch in front position (my mistake) with ignition off.

If I leave it in ride position the front stayed up for 2 hrs with that bottom port plugged up but eventually dropped down, whole.front. If I take the plug out, air rushes out and the right side drops, left front and rear stays up in ride position for a while.

[Tim]

This is dangerous territory trying to analyze level low system leaks or problems for a variety of reasons. First, I think unlike most systems today the coach in question might have the “reverse logic” and in order to maintain the coach at a given level the aux air system has to be pressurized at least 30 to 35 PSI all the time.

I also think the coach does have 5 port valves in the rear, but they are out of sight in front of the drive axle forward fender liners. But we are not at the coach and cannot tell what is true and have to rely on posted information to be accurate.

Older coaches with unknown history can act in an unexpected manner because a poorly maintained air system in the past can put water in the valving system and make any and all advice or conclusions about problems completely off the chart.

Lastly, the valves are definitely old style which suggests the potential for leaks in old valves and fittings and air bags is high so even if we understand fully the situation the simple answer might be to start from the beginning and replace all valves.

[Archived]

What comes to mind for the front going down is a bad Haldex ride height control valve or relayed Norgren spool valve, K910026 = K41EA00KS1KS2

or for the left and/or right

Leaky Norgren 5 port/3 way, #K910058 = K81EA00KACKAC, like Jon said, there are 2 of these on the bulkhead forward of the drive axle.

Below is what my bus has for Norgren valves, your results may vary?

Norgrens: 10 total, 5 in the front and 5 in the rear.

5 in the front if you have the AUTOMATIC leveling option, 3 if not.

Just inside the steer compartment door on the bulkhead to the right is a K910026 = K41EA00KS1KA2, and a K910058 = K81EA00KACKAC. Then just fwd and above the steer axle is a K910026 = K41EA00KS1KA2. Then on the floor of the steer compartment, if your bus has the automatic leveling feature, there are two K41EA00KS1KS2.

In the rear, there are two # K910058 = K81EA00KACKAC on the bulkhead just fwd of the drive axle, then there are 3 more on the inside of the frame rails above the tag axle. Their part #s depend on your buses tag logic/mod status.https://secure5.volvo.com/technicalpublications/pdf/Sb96-14B.pdf

[needtocamp]

Hi Don,

With both being Norgren valves, why the two different numbers.

K910026 = K41EA00KS1KS2

Donald

[Archived]

Donald, At some point Prevost had Norgren assign proprietary part numbers to standard Norgren valves to lead people to buy from Prevost.

[Archived]

First thing to note is that the Prevost level-low system works like this: the front can go up or down as the air bags are fed through a common line. The right side or the left side can go up or down. So that the we really triangulate the coach in to a position of level. If the right or left front appears to go down it is because the rear air bags on that side are the cause.

The picture above shows the Norgren valves for the the front system (5 way Norgren and the air supply valve for front, left or right. Your front 5 way valve connects to the t-fitting on the top of the air supply 3way valve, electrically operated.

When the coach is turned off, all three 5 way valves (front, left rear and right rear) receive no control pressures at the control ports. The spool valve inside blocks all the ports of the valve.

The three way valve in the picture above is connected such that the exhaust port is open. The other lower port is the air supply but it is not active when the coach is off.

If the vehicle leans to the left or right I would look at the rear five way valve for that side as it is leaking the air for the airbags back through the valve and exhausting it in the front via the blue line that comes into the t fitting on the top of the 3 ways valve up front and comes out the exhaust. It should be the 5 way for the side going down.

With the age of the vehicle and the valves that I see in the picture you have the original style Norgrens. The ones used now are better in that they are better suited for corrosion. Plus the condition of the pneumatic system and the amount of water that the se valves have seen can cause them to leak.

See if this helps with your air leak.

[Per]

It make sense now that somebody that really knows explains it.

The air from the T with blue lines will have direct line with the open exhaust on the bottom of the 3 way.

Theoretically, if any of the 5 way valves on the blue circuit are leaking internally, the air will be bleeding through the NO exhaust, top into bottom of the 3 way below.

I ordered 3 new K81s and will change them all….but….Where exactly are the locations of the 5 way in the rear ? I had the shop change all 4 of the 3 way in the back last summer.

When I spoke with David Coulombe and Dennis Orner back in April and got the 3 way valves, the diagram did not show any 5 way in the rear….showed 4 K41’s, 3 for leveling and one for inversion…..no 5 ways

Appreciate the assistance.

[Archived]

Marius, the front 5 port should be on the steer compartment wall near the 4 solenoid valve stack and as I mentioned above on your vintage the 5 port valves in the rear should be in front of the rubber drive axle fender liner.

Keep in mind the leaks on Norgrens can be thru the valve but also they can leak sideways past the spool and out the end caps which are not sealed so you cannot assume the valves aren’t leaking until you verify they are not leaking sideways or through the valve.

[Kirby]

Thank you Jon. I’ll look this afternoon. The new 5 way valves should be here Wednesday.

[Archived]

Marius,

I am pretty sure the 5 port is a three way valve and the 3 port is a two way valve. Someone will confirm or correct me if I am wrong. I hope You get Her fixed, the leans just plain ole suck !

[Dan]

That is correct….5 port 3 way, 3 port 2 way….terminology not correct …my bad….but you all know what I meant.

I took the 3 way upfront out to prepare the fittings transplant to the new one when it arrives and now I can’t use the bags to lift the bags and crib the bus on blocks to look for the rear valves….

[Tim]

I have had sticking Level Low valves especially if I haven’t used the system in a while. Now I make sure the AUX air pressure is at max (125 psi)* before I operate Level Low. This helps the valve spools move with more force.

As with all systems on the bus, I have learned exercising them regularly is necessary for trouble free operation.

Gerald

*.. To get max AUX pressure I turn on high idle and fan the brakes until the compressor cycles on. Once it reaches max pressure I use the Level Low system

[Archived]

Non-use does contribute to leveling system valves becoming lazy, especially if the system has ever had any moisture. All valves, spools and O rings in them come with a pinkish lube to maintain a slippery surface to allow the parts to move freely, but if any moisture has ever gotten into the system the raw aluminum surfaces in the valve body can corrode and the grayish sludge that forms starts to create a drag on the moving parts such as the plunger that moves the spool or the spool itself.

I have seen valves with so much sludge due to internal corrosion that the valve was effectively locked and would not move even at full system pressure.

[Art]

Started a new thread….leaning not resolved even after changing all Norgrens