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Mac/air valve replaced and I have an issue.


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2000 Dynasty. last fall my step cover would hardly move and Air was hissing. Found out this is a MAC/air valve issue.  Valve replaced. I was very careful to take photos and mark the lines. Photos must have been deleted I can not locate them. 

Air step cover moves so fast with the new valve it is scary. It is like there is no slow bleed like I had previously.  The real issue is my Park brake will not release and the coach will not move.   I am just positive the lines are on the same as the old valve but I must be wrong. Am I safe to switch lines and try them on a different port? There are three air lines and two wires. I switched the wires and nothing seems different.  TIA.  Update. My Haldex Purge is putting out some oily water. New haldex filter kit installed april 2018 and 4 k miles.  Coach is Stored in climate controlled dry building. 

Edited by rusty@kramermetalfab.com
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That Mac valve should have an adjustment screw on its side. I also slowed mine down so it would not hit so hard. Don't know about your parking brake, mine have no effect on each other.

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This thread is just what I needed! I have read all of the threads describing the screw action of the step cover and we do not have that on our 02 Windsor. Our cover has been problematic for a good while. It will come out but will not go back in without pushing it but occasionally it worked just fine.

Thank you for the information but can you please direct me to the location of the valve?

Sharon

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36 minutes ago, eddie4ne said:

This thread is just what I needed! I have read all of the threads describing the screw action of the step cover and we do not have that on our 02 Windsor. Our cover has been problematic for a good while. It will come out but will not go back in without pushing it but occasionally it worked just fine.

Thank you for the information but can you please direct me to the location of the valve?

Sharon

Ours is on passenger side by the front lower generator corner.

Screenshot_20210705-120508_Gallery.jpg

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Update, Located adjuster/bleed screws to slow down the step. Thanks Ivan! Brakes were rusted from a rainy trip before parking it for the year. Got them loosened up. Thanks to all.  Eddie, The mac valve is usually the issue with the step cover. It was for me. Be sure to buy new air line fittings. I also bought a screened port for the Exhaust. Mine was open and it sure seems like it could get dirt in it. 

 

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  • 2 months later...

Had an air leak and I'm not sure what I've found.  On the front firewall, there are three different things.  Two look like "mac" valves the other I have no idea what it is.  One of the valves that looks like a Mac valve had a tee in it and a line that comes off and runs down to the other valve that looks like a Mac valve and actually says "mac".  I assume this is the one that goes to the step well cover?  At least it matches the one in the pictures above.  The 1st Mac looking valve I have no idea what it feeds and it is so high up and covered by a wiring harness that I can't get a very good look at it.  Does the heat/AC use an air line?  The other one is located in between the other two but not feed by the same line as best I can tell.  Anyone have any idea what these three things are? 

 

Second question mostly unrelated to the first...is regarding what I think is the air compressor governor.  There are two pictures of it.  It is mounted to the frame rail right next to the engine.

Third question, where do you source these parts?  The mac valves and the governor? 

Thanks as always.

Jim

Step well valve.jpg

middle valve.jpg

Top Valve.jpg

govenor.jpg

Govenor 2.jpg

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We have 2 Mac valves up front. Step cover and door bladder.  Could the third one be for your air horns? HVAC should use vacuum, typically. You governor is likely Haldex 18530. All these parts should be available at NAPA truck parts and many online places like Finditparts dot com.

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I have two MAC Valves, one for the step cover and one for the air horns. The Dash HVAC is controlled by Vacuum which comes from a Vacuum Generator.

Monaco also uses something similar for dumping the Air Bags.

 

image.png.22d47f244f26bb289a52ddfd9072eb49.png

Edited by Dr4Film
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10 minutes ago, Jim Bob said:

Might be the air horn, but don't have a door bladder, the other is the step.  Would there be a valve for the "Air Dump" switch?

Could be your air dump, easy to confirm?  Ours goes through sixpacks since we have no Jack's. I only have air dump for the tag axle lift and it is at the rear.

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