Quote:
Originally posted by Bob86ZZ4:
Ya, the air bags usually have a dump switch that lowers the rear to the stops. ... But, there must be some rear suspensions that will allow you to max the rear air bags and lift the back up to full up. I wonder about that. Seems like if you can dump it you should be able to max it.
|
Bob and Gene,
I have the same issues with the back of our truck. We are always going to far-away race tracks that are off the beated trail and sometimes OFF-ROAD, some more than others. It is usually a dirt road that dumps out into a field or something, but getting there can be interesting in the coach.
I have always been concerned about dragging the rear of the coach since we built it. I have done a couple of modifications after talking to a bunch of different people about how to “lift” the back.
The first approach was to add a pneumatic cylinder that extended the arm of the dump / level valve to fake out the rear. That lifted the back by about 4”. This worked fine but there was only one valve for the rear of the truck located in the center. Since the load wasn’t totally equal from left to right on our coach with gen and slides on one side, I wanted to level the coach from left to right as well as adjust the ride-height.
About a year into this adventure I removed the air cylinder mod and added a second dump valve. Now I have one dump / level valve on each side. This levels the truck from side to side independent of the load. I use the trucks pneumatic dump valve switch to lower the coach when parking before leveling the coach if I want the back lowered before I start the process.
I then added a check valve and an electric air valve that floods both left and right side airbags downstream of the dump / level and takes them up to full height. This gives me about 3” additional lift at the axel and more at the back of the coach. I don’t run like this other than clearing curbs or dips in the road.
It does pass a lot of air with both dump valves open trying to correct for the additional lift. There is more than enough available to deep it up. And since it is seldom activated for more than 3 or 4 minutes at a time, I have never had any issues with low pressures. That being said, I am sure our DOT buddies would have a cow but since I am registered as an RV the DOT doesn’t worry about me.
This seems to have worked pretty well for us over the last few years.
Rad