i have a 02 reg version 1 fh12, she is putting one side up higher than the other on the midlift, which leaves one wheel touching the floor of the trailer and the other wheel still on the ground? anyone have any ideas what could be doing this?
it sounds like either an air bag leaking or most likely a valve not working
make sure there is not a trapped or kinked air pipe to lift bag. is the main air bag fully deflated ?
ther is no kinked pipes and air bags are ok, so it must be a valve somewhere
its the big block of valves sure its near to the n/side front wheel, not sure now been a while since i had anything to do with them and it aint cheap 500+ for the mid lift valve from ovlov 
Hi,
Presumably you’ve checked for obvious audible airleaks, and got none. The small airbags inside the chassis that lifts the axle are fed from one pipe that T’s off into the two airbags under the cradle, below the airbags, so you shouldn’t get only one small lifting airbag inflating unless something is seriously wrong!
Get someone to press the button up to lift the axle up and watch what happens to the airbags. The small bags on the inside of the chassis actually lift the axle, but to do so the large airbags on the outside of the chassis must deflate. Otherwise one’s pushing up, the others pushing down so the axle doesn’t go anywhere. I’m thinking that one of the big airbags on the outside of the chassis is not deflating, so one side of the axle is free to lift, but the other side is stuck down, making the axle cockeyed.
If this is the case, it is probably a fault in one of the solenoid blocks mounted on the inside of the chassis rails. They look like a square/rectangular block with pipes and a wire coming out. Be warned, these are very expensive new (£500-700), may be worth trying to find a 2nd hand one.
If the outer airbags are deflated when the axle is lifted I’m not sure what would cause it, would have to take a look at it.
Hope this helps