On my way home from Florida I started feeling strong vibrations in the coach, similar to rumble strips, but on smooth road. Slowed way down and rolled a mile or so to the next exit.

Rolled into the nearby small truck stop. Inspection revealed the rear end of the coach was riding low. No air in the rear suspension bags. The vibration was the drive shaft, due to the low body the shaft was not inline.

Further inspection found that the lever arm on the rear suspension leveling valve was broken off. The valve is bolted to the bottom of the coach. It has an arm that is attached to a rod that is attached to the rear axle. As the axle moves up and down, it moves the lever arm. The valve supplies air to the air bags as needed to maintain level height. The plastic cracked and the metal arm broke loose.

I removed the valve. I was able to tell it was a common valve, Haldex #90054007.

Being Sunday, nobody local was open. On Monday morning I found no local "mobile truck repair" shops that had the part or were interested to get me one. I ordered one from Stengelbros with overnight shipping. It took until Tuesday morning to get another valve. It was frustrating to discover that even close to a major city I was not able to get a part locally delivered.

Considering the valve is mandatory for driving and not too hard to install, I would recommend getting a spare. They are not very expensive. All three valves on the Monarch are the same, so one spare would suffice. If I had had one I would have been on the road in another hour or so.

I will soon replace my front two valves, as they are also 25 yrs old.

(Meant to post this a while back...)

The part arrived early Tuesday AM. Installed the new valve and replaced the rubber ends on the linkage rod. There are 2 bolts holding the valve to the chassis, 2 air lines, and one bolt on each end of the linkage rod. Make sure the rod length is the same. There are 3 ports on the valve for air lines. The center output port is connected to the air bags. The lower port is used for the input air supply. The top port has a short hose for a vent.

Fired the engine, the suspension went right up to normal height. The driveshaft was now level and looked fine.

We got on the road and made it home without incident. Had I inspected these more or had a spare aboard, I could have saved a couple days parked. Could have been worse.. We were in a safe level parking lot.

Finally got around to the front valves. They are easy to get to, mounted next to the shock absorber. Inspection revealed one had been replaced some time ago. Both sides had cracked rubber ends on the linkage. One broke off when I unbolted it. Be sure to check/replace the rubber ends.

If you look closely at the top of the rod you can see the cracked end. Be aware that if you order a replacement valve, some include rubber ends, some don't.

I replaced the valves and the rubber ends on the linkage rods. I need to bubble check the air lines and measure the ride height. Easier than replacing the rear valve for sure.

I should not have to worry much about the air system now. All height valves and air bags have been changed, as well as the air dryer. If I had known better I would have replaced the valves when I got new air bags.