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Do I have a problem or is this normal?
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If air is coming out in the closed position and you turn it to the 4 o’clock position for the air to stop. Will it effect the belt tension? In other words, the air stopped but will it change the belt tension?
Harry
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I think it locks the air in there, Harry, but my leaking cylinder makes that a moot point. As Jon mentioned, there’s no way of knowing what’s happening inside the valve and when it will fail further.
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Just some free advice………..That valve is intended to either open a path for regulated air pressure to enter the belt tensioners, or to close that path and block regulated air pressure while opening the path for air to exhaust from the tensioners.
If the air stops leaking you do not know at that point if you are keeping air flow to the tensioners or if you are just blocking air flow to the tensioners and the exhaust. The huge mistake would be to go to the center position because if air flow to the tensioners is blocked then as they leak down the belts are going to go slack and the fan will stop spinning.
The free advice is this……fix it Harry. The leak is likely driving you crazy so find it and fix it but don’t think you can cure it by using the valve in a manner never intended. Unless of course you like learning stuff the hard way.
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In a bind one could remove the line from the valve that feeds the mini air bags. And place a schrader valve if You have the right fittings and air up manually to get You Home, Or to a shop for repair. Ten dollars in parts could save You a fifteen hundred dollar tow bill. There is a schrader valve on my fittings next to the valve already. Most likely is to check pressure and dial in the regulator to the correct PSI. A small assortment of fittings and plugs might be a good idea to keep on hand ? Just saying
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Rocky your suggestion is valid if the system is tight, but if the cylinders or bellows leak air you have to stop as often as necessary to repressurize them.
One thing never to fool with on a coach is a cooling problem because a perfectly fine motor can be converted into a boat anchor very quickly.
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There is not much inside that valve. It can’t be worn out from use. So it has to be dried crack “O” rings or it needs some valve grease.
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Well, this is interesting. I replaced the valve with a new valve, but there was no change in the symptoms. I’ll spend a little more time wrapping my head around the problem, but I thought I’d get that out there in case Harry was about to order a new valve. I’m going to scratch my head now…
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I do not see any picture using my iPhone to read this post.
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Hi Chad, ETLC put it in so I’ll let them figure it out?
Hi Ron, I don’t know what you mean about your iPhone but what year is your Hercules Coach? When I attended the maintenance seminar last month I saw a couple coaches from converters I’d not heard of before? Not a big surprise because I’ve not been around Prevost all that long, but I’ve not heard of Hercules Coach?
I do remember the movie “Hercules vs The Cyclops” however! Not to give away the story line but Herc got Cy in a headlock and it was pretty much over at that point. I have no idea what all that means but if you can’t see the movie on your iPhone you may well be in serious phone trouble!
Harry
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I’ll probably write this up in a separate post when I figure it out, but I think I’m on the right path. I think the valves are both operating as expected. What seemed like a leak in the valve is actually the leak from the fan belt tensioner just following the path to the atmosphere, which takes it through the valve. I made a drawing which helped me work through the logic of it, and I think it’s now apparent why the valve shuts off in roughly a 45 degree position.
I removed the fan belt tensioner cylinder and will take that to a hydraulic shop tomorrow. I hope to be able to give an update of my success next week!
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Perfect example of “a picture being worth a thousand words”. Great drawings. What kind of software did you use to do that with?
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Everybody should keep in mind that Chad, Harry and others who have Prevost OTR in an 8V92 powered coach have brass belt tensioning cylinders.
Later model coaches have miniature air bags. I cannot remember if the valve/regulator/air bag set up is plumbed like the valve/regulator/brass cylinder set up Chad shows.
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Dick, I’m a little old school. I used Microsoft Paint. 🙂
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As I was suspecting when I made that last post, the problem was not the valve. Air was leaking through the fan belt tensioning cylinder, and then passing through the 4-way valve. I had to have a hydraulic shop repair the cylinder because the locking wire had broken off in the end cap. It would have been a fairly simple repair otherwise. Prevost had all but one of the o-rings and seals in stock, but their shipping date was late December. I let the hydraulic shop supply them instead. They reused one seal that wasn’t on hand.
I broke one hose end when I went to reinstall the cylinder, so that delayed me another week while I waited on parts and tools to make a new hose. I put it all back together today, and it is all working perfectly! Here are some photos.
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I couldn’t edit the caption on that last photo, so here’s the photo showing the battle scars on the air cylinder.
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