When changing the D2 air governor on a ISM, is it easiest via rear hatch, or from underneath?
I did ours from the rear. Wasn't that difficult.
From the underneath, aft curbside corner, after removing the mud flap. 30 minute job. Woody.
Adjusted the old D2 this moring, 3/4 turn counter clockwise. Did it from the rear.
Only 150 mile run today, "might" change the D2 out next stop. Think I wi need access from both under and rear hatch for changeout.
Update and completion.
Before 150 mile run, adjusted original D1 3/4 turn counter clockwise - raised air pressure as shown on gauges 10 - 12 psi cut in and cut out. Each 1/4 turn should equal 4 psi change.
At end of 150 mile run, in a gravel rest area OK for over night stays 18 hour max (MIllers Rest Area 12 mi north of Tonopah NV), changed out the D1 to a new one I had on board.
For my particular coach (2003 U320), adjusting the D1 works from rear acess, but changing required working from underneath.
13mm socket to remove the 2 bolts, and for fittings (the 2 airlines) one 1/2 ", two each 9/16" wrenches, and a allen key wrench I did not check size of.
I had permatex thread sealant on board and used on the 2 large fittings. The allen screws came with sealant on them.
I took photos so I can prepare my replacement on board D1 spare in advance. Posting here for others who's fitting locations may (or may not) match.
You are much faster than I am. I struggled with removal.
But your access method worked great and I feel safer with new D1 installed. I see some contamination looking in the ports of the old one. And PSI cut in and out had dropped on the old one.
If you need another project (when you get bored) you might hook up a pressure gauge that will show the pressure in your wet tank. Get a gauge and a short length of suitable tubing + some fittings. Connect one end of the tubing to one of the unused bottom holes (marked RES) on the D2 and other end of hose to gauge. Mount the gauge on a simple bracket so it is visible when you look through (or open) the engine bay door.
Knowing what the pressure is in the wet tank can be very handy when diagnosing air system problems. See post below:
Dash Air gauge has two indicators. one white, one red.. ??? (https://www.foreforums.com/index.php?topic=24878.msg195836#msg195836)
Tubing I used: JEGS 41057: Mechanical Gauge Hose Kit -4 AN Braided Stainless Steel Hose [3... (https://www.jegs.com/i/JEGS/555/41057/10002/-1)
The air pressure gauge I used was one I had on hand in my spare parts kit - source unknown.
What's the P/N for the governor? Or can I just go into napa or a fleet services store and ask for a D2 Governor? About to replace all my ride height valves and might as well do this while I have the coach blocked.
NAPA, Amazon, Ebay. I have been spending a bit more and getting Haldex new old stock on ebay. Not reman, new
I've found it better/easier, to break loose the hose connections from the D2, while it's still bolted to the coach. And take a photo of the hose pattern position.
air governors come in non adjustable or adjustable
Put mine in this morning. I agree with Dave, it was easier for me to remove the lines first then unbolt. The adapters between the hoses and the governor were seized in there so I would recommend buying a couple of those at the same time as your governor.
I went with a re-manned halidex and just an FYI that they require a 3/16 allen wrench to install the plugs. Not a common size that comes in every set and there isn't a metric equivalent. Fortunately I have a box where extra/one-off tools go to die and found one there :)