skinner valve solenoid (problem solved)

[David Anderson]

Got a dilema.

I bought a new (rebuilt?) skinner valve solenoid from Jefferson Truck back in November.  It worked a few months then wouldn't release to start the coach.  Jefferson graciously sent another one and it worked a few months and now on a trip this weekend won't release to start the coach without me rapping it with a screwdriver or wrench.   When I hit the thing with a screwdriver handle it slowling releases air, speeding up then psssst!! to full open releasing the stop cam. 

I doubt Jefferson will give me another one, but darn I paid $86 for the the thing and two of them only lasted a couple of trips.  Any ideas?  If they read this post maybe they will give me a 3rd one.   

David

[buddydawg]

If it is sticking have you tried lubricating it?  Any amount of corrosion will cause it to hang up.

[buswarrior]

Take the connection apart and feed it a dose of air tool lube, cycle a bunch of times, and see what happens.

happy coaching!
buswarrior

[Dreamscape]

I wouldn't put too much air tool oil in it, it may gum up. You could use any type of thin oil to lubricate.

Paul

[Sammy]

Which component is giving you trouble - skinner valve or skinner valve solenoid??
Electrical or mechanical component?

[Stan]

Some random thoughts: The Skinner Valve used to stop your engine is a normally open valve which allows air to pass to the shut down cylinder on the top of the governor. In order to start the engine, you have to apply full voltage to the valve coil to close the valve and allow the air in the cylinder to bleed out the exhaust port on the valve.

Have you checked to see if you are putting full voltage to the coil?

The valve is designed to operate on dry air and doesn't require lubrication and is non corrosive internally. If you have water in your air, it could be causing a problem.

[Barn Owl]

I would agree with Stan, check your voltage. I have found that many of the solenoids on the bus need 12 plus volts to function properly. Jump it with leads directly from fully charged batteries and see what happens.

[David Anderson]

I'll check the voltage.  The goofy thing is once I tap it with a tool the solenoid lifts the internal plunger and bleeds the air releasing the skinner valve cam.  I can turn it on and off after that and it works fine.  There is nothing wrong with the skinner valve itself.  I'm only descibing a problem in the electric solenoid switch. 

It wouldn't be overpressured with air would it?  I don't think there is any regulator on that line.  I believe it is full pressure from the main air tank.

David

[tomhamrick]

My model 10 is supposed to have a 90 pound regulator before the skinner valves but it was missing when I bought my bus 9 years ago. I keep saying I will replace it one of these days.
Tom Hamrick
1984 Eagle 10S

[Barn Owl]

Think of voltage as pressure, you might have just enough to almost overcome the internal friction, and then you hit it with your hammer, which jolts it just enough to work. The higher the voltage, the stronger the magnetic field, and you need that level of force to operate the valve. My only concern with this theory is why would it take a few months to manifest this problem if it is low voltage. At least it is one of the easiest things to check for and eliminate.

Good luck,

Laryn

[JackConrad]

Bad ground connection?  Remember that voltage not only has to get to the solenoid, but it has to get back to ground.  Jack

[Stan]

quote  "I'll check the voltage.  The goofy thing is once I tap it with a tool the solenoid lifts the internal plunger and bleeds the air releasing the skinner valve cam.  I can turn it on and off after that and it works fine.  There is nothing wrong with the skinner valve itself.  I'm only descibing a problem in the electric solenoid switch."  unquote

There is so much incorrect terminology here that it doesn't make any sense. The V5 series Skinner Valve used on a bus shut down is 1 5/8" in diameter and 3 13/32" high. It is manufactured by the Skinner Valve Division of Honeywell Corp. ( Thus the name Skinner Valve). It is an electric solenoid operated valve. This particular model is designed to operate an air cylinder. When no voltage is applied the valve is open allowing full air pressure to the shut down cylinder on top of the governor housing. When voltage is applied the valve closes off the air supply while allowing the air in the shut down cylinder to exhaust through the exhaust port. No air will come out of the exhaust port unless the shutdown cylinder retracts, so if it is sticking there will be no air exhausting and no engine start.

That is the whole system as is it is used on buses. There is no skinner valve cam and there is no electric solenoid switch. I don't have the wiring diagram for your bus but as someone else pointed out, the voltage to the Skinnner Valve likely comes through the relays that are operated by the safety shutdown switches.

If you need any more details on the Skinner Valve, give me the numbers of the tag on top of the valve and I will look it up.

[David Anderson]

Yes, I am talking about the electric Honeywell solenoid valve as my problem.  I doubt it is the air cylinder that pushes the stop cam because I can loosen the the SAE nut on the air line and the and bleed the air and the plunger quickly releases the fuel stop arm.   Therefore, the plunger is not sticking. 

When I get some time I'll check the voltage, easiest place to start.

David

[artglass]

  i'm having the same problem, seems as mine is in the plug on the wire doesn't always make contact with the solenoid, i checked to see if it was the clylinder or the solenoid by taking the air line off.  if you have a part #  for that plug it would be greatly appreciated.

[Stan]

David: Read again my explanation of how the system operates.

When you have full air pressure on the bus, shut off the engine (push the stop lever by hand if necessary) and then turn on the switch. Make sure that you have full battery voltage going to the coil of the Skinner Valve (Stick pins into the wires after the plug to measure the voltage). Take the line off the shut down cylinder. The air should exhaust out of the cylinder and the piston retract. There should be no air coming out of the line.

If the piston does not retract, something is sticking in the cylinder.

If here is no air coming out of the line, then there is a blockage in the exhaust port of the valve, stopping the piston from retracting.

If there is air coming out of the line, the valve is not shutting off.

Skinner Valves are easy to service and rebuild. Remove the valve from the bus and put it in a vise to work on it. Remove the exhaust fitting and O ring and the nut holding the coil assembly. Remove the coil assembly by lifting straight up. In the top of the valve body there are two holes for a pin wrench, which you probably don't have, so use a punch to loosen the part (standard right hand thread). Remove the top of the valve. Inside is a plunger and a spring. Make sure all the orifices are clear and the inside of the valve is clean. A rebuild kit consists of a new plunger, spring and gaskets. Kits are available from Skinner Valve dealers. You need the complete valve number to get the correct plunger. All large cities will have a dealer, so look in the Yellow Pages under Industrial Valves.

I just took a quick look for Skinner on line and apparently they are now tied in with Parker but I don't see a convenient list of their dealer network. More searching might bring up the list.

I just checked your location, and I have bought Skinner Valves from the dealer in the north end of San Antonio. Sorry, I don't remember the name.