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EL-II Level sensors and where to get them
EL-I vs EL-II
ONE-SIDE LEAKDOWN TESTING
El Troubleshooting By
EL troubleshooting class 301, with the sub-title "what
the &^$% is wrong with my 3 way valves?"
Before we start, heed this advice from Prof Arch, who writes with wisdom:
>Check the little arms that go between the bogie and the ride level
>controller. The rubber on each end of mine was shot.
Here's a simple test:
Put both sides in the raise position. Wait on the coach to go up. Center switch in 'auto', left and right in the center. Get out, walk up by the rear wheels. In 10-30 seconds, you should hear the hiss of air being let out of the bags. It isn't real loud. Your valves must be able to 'break wind' or they are mis-adjusted or bad. You must first solve this problem if it exists.
1). Adjust or replace the ride height valves.
2). Live with it. Use this procedure:
A). Set level to 'auto', let the coach level, compressor turn off.
B). Set level to 'hold', occasionally to 'auto' about once an hour while driving if you feel
your butt's dragging.(The coach, not yours).
3). Fix or replace the bad 3 way valves.
EL I height creep can be caused by leaking 3 way valves. We're talking about the three way valves that are mounted on the common air pressure manifold. This is easier to understand if you go to http://www.california.com/~eagle/figs/off.gif and print that schematic. Thanks to Al Chernoff and Eugene Fisher for a job well done. (see the top of this page)
Be aware now, before you start, this is going to get involved. You might want to take a Polaroid of the whole thing so you don't get lost.
I don't remember which side you said was creeping up. If I've picked the wrong side in this example, refer to this drawing for the correct colors. I'll detail this using the passenger (right) side of the coach.
Here's the technique:
1). Safely block the rear suspension of the coach prior to using the rocker switches to fully deflate the bags. I'd suggest a jack on the troubled side to make this easier.
2). Make sure you've got all the air out. Take the blue line from the air bag off the two way valve. Take the two way valve itself off the three way valve, or (if you can) take the second three way valve off the first three way valve. What ever works for your coach, leave the first three way valve connected to the pressure manifold. For the moment, leave the yellow air line attached to the valve.
3). You now have an open port on the three way valve. It's showtime.
4). Take off the wires that feed the driver's side two way valve. (Light green with a double black stripe). The driver's side two way valve is the one with the grey air line. We're going to take the driver's side air bag out of the circuit for a moment while we run some tests.
5). Depending on the pressure that's left in your air tank, it will vent when you take this next step, so be aware.
6). Turn on the ignition key and set the center EL I rocker to Auto. Air will start to come out of the open valve port. This assumes that the coach is below normal ride height, and the ride height control valve is calling for more air to be put in the bag. (If you jacked up the coach *above* the correct ride height before you started, this won't not happen.) For the moment, we'll assume that the coach is below the correct height, and that air is flowing out of the open three way valve. If you're following along on the printed schematic, this air is coming from the yellow line.
7). Turn off the key. Go outside the coach and disconnect the connecting link that goes from the boogies to the height valve. Move the height arm in the direction that would turn it off (against the internal resistance). Or, safely raise the coach up with a jack.
8). Turn on the key. Depending on how reactive your ride height valve is, air will stop coming out of the open three way valve port. If it doesn't, your ride height valve is shot. (We'll confirm that in a moment, but for now, we'll assume that the air flow has stopped, and the compressor may even shut off.) Get your soapy water spray, and soap up the open valve port.
9). Are there bubbles? This comes from only two places: the ride height valve is leaking through, or the three way valve is leaking through. If there aren't any bubbles, then you need to check how well the 3 way valve seals by cycling it.
10). Go to the EL I right rocker switch and push it to raise. Air will come blasting out of the valve opening. Flip it back to center, then to raise a couple of times. Back to the center and check for air leaking through the valve again. If you now have bubbles, its the three way valve that's bad. If you always had bubbles, then we'll isolate where the problem is.
11). With the activator link on the ride height valve set as if the coach was at height or the coach jacked up, turn the ignition key on, move the right switch to raise and let off the air pressure. Turn off the key.
12). Take the yellow line off the 3 way valve. Center switch in Auto, right switch in the center position. Turn on the key and get some air pressure building. Is air escaping from the yellow line? Make sure the coach is above ride height, there should be no air flow. If there's air coming out of the yellow line, then the height valve is bad. Replace it.
11). If there is no air flow from the yellow line, check the open ports of the three way valve for leaks. If there is any air leaking through, you've found your culprit. There should be no airflow through the valve when it is off. Replace the three way valve, and reassemble everything.
(Note that it only took me three words to cover about 2 hours worth of work there at the end.)Remember to always work safely.
HEIGHT CONTROL VALVE REPAIR
Remove the L shaped spring clip retainer (#13) that holds the lever to the control arm of the valve. This clip is also a retainer for a rubber plug that is held in by the spring retainer clip. Remove the rubber plug and then you can look at the shaft and see if it moves when you work the lever. Hold
the lever to either position long enough for the shaft will be slow to move, as the valve has a delay system built into it. After approx. 10 or 20 seconds the shaft should slowly move, but not very far. For a better look you can also remove the four screws that hold the L shaped mounting bracket
to the valve and witness the movement of the Y shaped yoke. The yoke operates the two schrader valves that control the inflating or deflating of the air bag. Do not remove the retaining spring or the plug on the round cylinder part of the valve as this houses the fluid that gives the valve the delaying action. There are three fine mesh screens that are held in by the screw-in adapters for the air lines and the exhaust nipple. These screens will become clogged from a contaminated air system and will cause a lot of problems with the air bag system. You can remove the adapters and clean the screens with carb cleaner and reinstall them along with new "O" rings. These are the adapters that screw directly into the valve body, and the nylon air line adapter screw into these. Bob Drewes
A GMC GreatLaker now has the capability to rebuild the height control valves back to new and they look new too. His name is Dave Lenzi and he can be reached by E-mail at email@example.com or 810-653-3902.
NEW REPLACEMENT HEIGHT CONTROL VALVES - EL-I
How about a direct replacement leveling valve from these people.
Looks like they bought the rights to the valve from GM and may even have the brass fittings to replace the plastic ones.
It appears that the NEWAY #90054007 is the most common truck/trailer leveling valve. Has delay, stated variously as 6-12 seconds. It may be a final option for us if Dave Lenzi can't keep up with demand for rebuilt steve
When you disassemble the valves, LOOSEN the three allen head bolts about 1/16th" and tap the side smartly with a screwdriver handle. This should separate the halves without tearing the seal. Very carefully loosen the seal from the front side of the valve. With luck you can reuse it. Once this is done, finish separation and remove the springs
Remove the O ring on the spring side of the valve. You can then push the valve out thru the front. If it hangs up, that's pitting and corrosion in the cylinder. Work it back & forth with some penetrating oil and push it on out.
Then it's grind valve seat, hone cylinder, polish piston, clean up and reassemble. Incidentally, my coach is still standing tall - like someone slipped it a triple dose of VIAGRA.
Also removed the hose - compressor to check valve - at the check valve to see if I could detect a leak back thru the valve. I could not, so reattached the hose. The tank pressure is now holding. Go guess----------. The check valve appears to be relatively new and is all brass.
Maybe you'll luck out, as I apparently have, and the leveling valves
will solve your problem entirely.
Look under the back end of an old Caddy with an automatic leveling
set-up. The arm and bracket will be different, but the basic valve
is the same piece. HTH
I found best cure for leaking level valves. I replaced them with new up grade valve assembly built by JR Slaten in Louisville, KY. Since replacing old valves, I go months without leak-down. Been using new valves about five years and am totally satisified. Give him a call if yours still leak. His number is:
e-mail at: firstname.lastname@example.org. Good luck. Harry
rotary air valve piston seals
I got this info at a Classic rally and did mine. They are like new. Use Viton “O” rings - 007 on top of shaft and 008 on pistons. 90 deurometer hardness. Got them on the net. You have to clean up the bore, seats, and I polished the gasket faces with 800 paper on a glass plate. Al & Carol Scott
I assume you are asking about the O rings in the dash mounted
These are #7 O rings that should be available at industrial suppliers
hardware stores. Use a little silicone grease when assembling. Denny
THREE WAY VALVE REPLACEMENT
One of my first "projects" on the "Noble Beast" after we bought it in '99 was fixing a few leaks in the ElectroLevel system. One of the 3-way valves had a cracked housing and I ordered a replacement from Gateway. I just found the box it came in (I'm a packrat, what can I say!), so here's the part #:
Honeywell Skinner Valve
C 4 DK 1 150DC11AD
95 Edgewood Avenue
New Britain, CT 06051
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