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WA198273 · 09-21-2021, 10:36 AM

After reading all the info here. Some applies. In our case it is Pneumatic. We replaced Mac Valve 225-B-60-1BAA and it made no difference. There is power to the step cover switch on driver side switch panel and power to the switch panel on passenger side. You can manually, with a lot of force, pull it out and when you let go of it it goes back forcefully under a lot of pressure. Help? Ideas?

Ray,IN · 09-21-2021, 11:13 AM

OK, compressed air operated. There will be an air pressure regulator that controls how fast/slow the cover moves. By manually pulling the cover, and it resisting indicates the control air cylinder is good.

There will be a 2-way, 12V solenoid-operated air valve that controls step direction.(location???) This is the likely trouble spot IMO. Test the solenoids for 12V power presence when using the cover's in/out switch.
It's been so long since I worked on mine I'm having trouble remembering.

WA198273 · 09-21-2021, 12:17 PM

Isn't this the same thing as the Mac Valve 225-B-60-1BAA. It has two electrical hookups and one Air. If so that is what we just replaced. If not I have no idea where to look.

Notn2bars · 09-21-2021, 08:25 PM

We have a 2000 38 Ft. Dynasty also. Our Mac valve has 2 electrical wires and 3 air lines. Did you indicate your Mac valve has one air line? God Bless, Ed

Ray,IN · 09-22-2021, 08:10 PM

Quote:

Originally Posted by Notn2bars

We have a 2000 38 Ft. Dynasty also. Our Mac valve has 2 electrical wires and 3 air lines. Did you indicate your Mac valve has one air line? God Bless, Ed

This valve should have an inlet line, another exit line (solenoid controlled) for extending the cover, a third line(solenoid controlled) for retracting the cover. This controls the double-acting cylinder below the step cover.

8.3Oilbuner · 09-23-2021, 04:40 PM

Hi WA198273; I have not looked up the MAC valve number you posted, but you mentioned one air line. Does your Dynasty have hydraulic jacks??? If so you have 2 MAC valves on the firewall in the gen. compartment. The MAC valve with one line is for when you dump the air bags for leveling. The one line to the valve is for letting air out of your 4 front air bags. The other MAC valve should be to your left of MAC valve with one air line and and as Ray described have 3 lines and is smaller in size the the MAC dump valve. If you can find the smaller MAC valve post a picture of it here for other's here to see if it is the right one.

153stars · 09-23-2021, 08:21 PM

I was able to disassemble clean and oil mine , it worked fine after. Put a little air tool oil in both cylinder lines. Clean and add a thin coat on cylinder rod wont hurt if you can get to it . Run it in and out wipe clean and dry again.