Webasto Valves

[dreamchasers]

Until Hector really got into it and made his power point program the air suspension systems were a black art.

Today, with the knowledge here, and with the guidance of Hector's power point program there is no need for any POG member to have the leans, or to spend serious dollars getting them cured.

Where is it leaning, what year coach, who is the converter, and I'll bet we can isolate the areas that cause your problem.

Jon,

I finally solved my air leak problem with the braking system and for the first time since I have owned the coach, the tag axle does not dump overnight due to loss of air. I have learned 'mucho' about the air systems. I have been thinking of developing another interactive learning tool for the primary, secondary and auxiliary air systems.

Are you up to acting as a technical advisor again?

Hector

[Darrell McCarley]

JON & TOM.......1989 Executive Coach Conversion(Fox River Grove, Il) out of business. 144K total miles. The left side air bags start to lean after 5-7 days in warm weather and less time during winter months here in Dallas, Tx. I have not been concerned because it does not leak down while driving. I have another problem that I could use some advice. I have 12v/24v house batteries with a cross-over switch to connect the house batteries with the engine start batteries. I leave this switch on when parked and pluged in to keep all batteries charged including engine start batteries. I also leave the switch on when driving to keep my house batteries charged. The cross-over switch is getting power to the silenoid (in and out) but no power to the rear engine start batteries. What could cause this problem?

[Jon Wehrenberg]

Hector,

Let's do it. I have found when explaining the suspension system that most look upon it as a big, huge complex assemblage. To aid in understanding I ask folks to think instead of three separate unrelated systems that share a common connection to the aux. air. Then when trouble shooting it becomes easy for everybody to focus exclusively on only the components within the sub-system.

My point is that the diagramming and teaching of the other pneumatic systems should be done in small blocks. For example, the rear brakes could be broken out and isolated so the system starting with the relay valve could be shown. The "signal" system from the foot treadle could be another block. Another could be the daisy chain of pressure tanks starting at the compressor. I think compared to the suspension system which has a lot of variations the primary and secondary air systems can be a generic presentation with almost universal applicability.

I know nothing about the ABS so I am not sure how to integrate that. I suspect that goes beyond what most want to get involved in, beyond flashing or reading the codes. I think most problems on ABS have to do with failed sensors anyway.

[Jon Wehrenberg]

JON & TOM.......1989 Executive Coach Conversion(Fox River Grove, Il) out of business. 144K total miles. The left side air bags start to lean after 5-7 days in warm weather and less time during winter months here in Dallas, Tx. I have not been concerned because it does not leak down while driving. I have another problem that I could use some advice. I have 12v/24v house batteries with a cross-over switch to connect the house batteries with the engine start batteries. I leave this switch on when parked and pluged in to keep all batteries charged including engine start batteries. I also leave the switch on when driving to keep my house batteries charged. The cross-over switch is getting power to the silenoid (in and out) but no power to the rear engine start batteries. What could cause this problem?

Darrell,

The Prevost standard for acceptability is if the coach does not lean in 3 days it is OK. That does not mean that you will accept that. Without knowing your coach's service history, or age of the components, there are a relatively few areas where your coach can be leaking, and with the slow rate the leak(s) may be difficult to find. If I wanted to trouble shoot the problem I would start by soaping the three air bags. That would not tell if the leaks are around the bottom "can" but it would rule out the top crimp, and any porosity in the rubber.

I would soap all the fittings on the three air bags, on the three port Norgren on the frame between the tag and drive, up high on the frame, and the 5 port Norgren in front of the drive axle fender liner.

Then I would use a stethoscope or ultrasonic leak detector to listen carefully at the five port Norgren in particular. With a leak as small as you have I would remove the air supply line from the ride height valve and the line to the three port valve in the front and cap both of those ports. (Air leaking sideways past the spools in the Norgrens would show up as bubbles at the end caps, but air leaking past the "o" ring to the exhaust would not because it is an internal leak) By plugging the two ports if the bus does not lean the problem is with the 5 port valve, if it leans a more extensive check of the air bags is likely to find it.

Now you know more than you ever wanted to know about how to chase that last leaking bubble of air. Or you could use Hector's bubble detector. He did promise to supply a drawing or a how to description of making one and using it.

Your bus is leaking down when you drive, but the leak is so small it is easily compensated for by the ride height valves. Cold weather always makes small system leaks more visible.

I would need to know more about how your converter set up the coach to fully address your question about the "cross over" switch. Generally converters try to keep the house and chassis batteries isolated from one another. The solenoid you mention could have been provided to tie the two sets together when you have charging current from your alternator(s) so both sets can be charged, or to provide you with a means to boost your chassis batteries in the even they don't have the power to start the bus.

Your chassis batteries should not run down when you do not heve the engine running. If they do there are loads on the batteries that should not be there, or you have bad batteries. I suggest you check for each problem.

As to why the solenoid is not getting power to the batteries may be as simple as a bad solenoid. It's an easy check to confirm that if the solenoid is getting power to the two connections to the coil, then there should be continuity between the big posts. I am assuming this is one of the silver solenoids such as you might find on the firewall of an older car.

[Darrell McCarley]

Thanks JON......The solenoid has two solenoids connected together with a copper strip. Both solenoids have 24v power from both sides with the dash switch activated. I must have another solenoid or connection further back toward the engine that is not making contact. When my friends shop pit becomes available, I'm getting under the bus to trace the battery cable from the house battery compartment to the engine batteries. Could be simple as a corroded battery connection. Thanks again for your input......Darrell

[Ray Davis]

Turns out the two 24 volt solenoid operated Parker valves immediately aft of the Wabasto were inop.

Jim, I finally got to check out my webasto this weekend, and I believe I am seeing the same issue that Adam has. AND, I believe you hit the nail on the head with respect to our problem.

In Adam's case, and it turns out, in my case the heater shutdown down, unless "Block Heat" is enabled. Well, in looking at the schematic, and feeling around for hot coolant in pipes, I've decided that the normally-open return valve is clogged up. When you use block heat, these two return valves are reversed, and coolant comes through the engine, and out the other valve back to the pump. That path is working for me and I believe it's working for Adam. It's possible (I'm guessing here), that if the previous owner had not used block heat much, then that valve would have generally been closed, and less susceptible to clogging.

So, I need to rebuild my system similar to yours, although I am not sure I want to add the ball valves. Can you let me know where to find the two valves that are used back there? There should be a normally closed, and one normally open valve, both 24V (in my case).

Thanks in advance.

PS: Contacted Leon about this, and he mentioned that for some of their customers with early era coaches, they are simply removing the guts to the two valves, and letting them both be open. I found this to be interesting news.

Ray

[Ray Davis]

PS: How do you accomplish this rebuild without a total mess? I'd rather not completely drain my coolant from the coach. Is there a way to block off the pipes long enough to swap in new manifold, as you've done here?

Thanks,
Ray

[truk4u]

Ray,

My Liberty heats everything with the Webasto running, engine, hot water heater, bay heat and coach heat exchangers. I like it much better than the previous coach's with buttons to open and close the various loops. Kind of simple, everything is on.

[adamdegraff]

PS: How do you accomplish this rebuild without a total mess? I'd rather not completely drain my coolant from the coach. Is there a way to block off the pipes long enough to swap in new manifold, as you've done here?

Thanks,
Ray

Ray, I got the low down on doing it without mess. There is a tool called "Hose Pinch Off Pliers." I am sitting with it on my lap right now. Napa #145. You will need three of them to isolate the area where you will be working. The hoses are reputed to be difficult to collapse. So I went with this higher end tool (about $25) that ratchets down and locks in place. I supposed a pair of vice grips or a pair of channel lock pliers might also work... but I really, REALLY don't want to damage my hoses. Once you have it all pinched off, Jim Purcell (over at Marathon) told me to prepare to do battle with the big round valve cover. He said it is a bitch to get off. It is also huge. I have a massive pipe wrench that should do the trick and provide the necessary leverage assuming I can get to it.

I'll let you know how it goes... once I find two more of the pinch off pliers. I tell you, being on the move 100% of the time makes it hard to mail order things. So I'm hitting NAPAs on my route and picking up the necessary tools. I'm thinking that once I get the valve open, I will just clean out the screen and put it all back. I assume the screen is there for a reason? Jim has a nice picture of a gunked up valve so you will know what to expect.

If you go first, let me know how it goes. If I go first, I'll do the same. I'd love a sweet set up like Jim's but don't have the brass to make it all work this time 'round.

Good luck.

Adam

p.s. yes, our problem is exactly the same and yes, you are exactly correct as to the fix. Jim confirmed all of this and seems to know more about this system than does Leon. Leon was certain it was my extra webasto pump located in the cruisair compartment.

[hhoppe]

Thinking out loud here. Could the webasto be getting it's electrical power from the same electrical outlet as the block heater. No block heater switch on, no webasto operation. You need to have working valves or at least manual operated ones to prevent hot water circulation from the engine flowing through the coach unchecked in summer conditions. Each converters schematic is probably different.