Community Forums

JMCruiser · 08-18-2020, 05:17 PM

We are new members so hope this is the place to ask a question about our 1998 Dynasty. We drove it home from Alberta to Saskatchewan and it worked fine. The next day we had it inspected for saftey certification at a truck shop. They did great work fixing a few items and said they fixed a leak in the air system that was coming from a valve they adjusted. We got it home The step slide will not work The switch is silent and the slide can be pulled out and pushed in but thats a pain. My manual is not very in depth as to things and I found a 2000 dynasty manual that refers to a MAC switch that runs off the primary tank and runs a Double action air cylinder.
So my questions are Does a 1998 monaco executive dynasty work with air for the step slide ?
Is it possible the well intended truck mechanic set the screw adjustment down to stop the leak and inadvertently disabled the slide from getting any air to operate?
Appreciate any experienced advice from this forum and apologies for the long story around the issue cheers

jacwjames · 08-18-2020, 05:52 PM

My 2002 Windsor has a step slide that is controlled by a Mac Valve.
It is located on the fire wall above the generator, it is blue in color and has black air tubing going to it.

I have never had to adjust mine.

The mac valve is controlled by a switch, on my coach there is a fuse in the drivers side electrical bay below the drivers window. I would check that first and then move to the mac valve itself.

8.3Oilbuner · 08-19-2020, 11:00 AM

Hi JMCruiser; Most likely the truck shop heard air leaking from the MAC valve and ran the 2 air pressure set screws all the way in until they seated thus not allowing any air through the valve to operate the step. As Jim mentioned the valve is in the gen. bay attached to the firewall. These MAC valves can get dirt and rust in them and that allows air to leak from the valve. Check the set screws on the side of the valve to see if they have been run all the way in. Use a jewelers screwdriver to back out the screws a few revolutions' and see if the step works. There are threads here that instruct on a method to try clearing the valve. Try first backing out the screws and post back if possible.

JMCruiser · 08-20-2020, 08:05 AM

Thanks for the great advice Oilburner 8.3 You where exactly right The shop looked at it and backed the screws out so the steps work The issue now is a leaking MAC valveAny ideas as to where I can get one online? Appreciate your help to a novice Monaco We are loving it so far !

jacwjames · 08-20-2020, 10:37 AM

Here is the Mac Valve for my 2002 Windsor.

If you zoom in and rotate you can make out the part number.

45A-AA2-DFEA-1BA

Here is one source but do a search, you might find it cheaper
https://shop.findmyrvparts.com/mac-v...A-p/190051.htm

8.3Oilbuner · 08-20-2020, 10:43 AM

Good morning JMCruiser; On the 2 Monaco Windsor's I have owned I have had to clear the MAC valve or the step because of air pressure leaking from the valve. To me I think small rust particles from the air tanks flake off the inside of the tank and get stuck in the very small ports of the MAC valve. This procedure has always worked for me, but if this does not work for you the valve might need to be flushed with something like WD-40 and or even replaced.

You will need a helper for this procedure. Get the coach up to full air. On the MAC valve run the 2 set screws all the way to the out-counterclockwise position. If I remember correctly there are stops to prevent the screws from coming all the way out of the body of the valve. This is going to allow the maximum amount of air pressure to move through the valve. Now position your helper at the front the step step. The reason a helper is needed as you are now going to toggle the step switch from extend and then to retract a number of times to blow out any particles in the MAC valve ports. This will make the step cover rocket out at a very high speed and the helper needs to slow the step down by slightly pushing on the step so the step does not hit the stop hard and break something. Do this about 4 or 5 times. You will hear a large amount of air exhausting from the MAC valve. This should be clearing the valve.

After all above is said and done, run the 2 set screws in-clockwise until they seat. Now back those 2 set screws out-counterclockwise 2 revolutions. Now check the speed the step moves in and out and adjust the set screws on how fast you want the step to extend and retract. Hopefully now the MAC valve is not leaking air pressure. See if this works and let us know how things shake out. Sorry for the long post but is the only way for me to describe how to do this. Good luck!