Hi All,
I’ve just aquired a tandem axle trailer on air and i’m struggling to figure out the controls for it. All the trailers I’ve used to date have only one lever for the air suspension giving you up, down & standard ride height. However, this one have x3 controls … x1 red, & 2x blue. any idea what these are supposed to do? I’ve fiddled around but can’t seem to make the trailer height change…confused I am !! Help please 
Got a pic of the controls?
Not all trailers have raise/lower valves, your buttons sound like Park/Shunt and Release.
Unless you have a lift axle!
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Photo of the controls attached. Essentially all I want to be able to do, is to drop the air suspension down for loading …but I can’t figure out how??
I’d say they’re park (left). Shunt (right) and lift axil (centre)
Pull them and see what they do.
As others have said, park,shunt, could be up and down, dumps all the air, ride height valve.
On all our trailers it looks like this :-
Which I think is pretty normal ? Usually at the back of the trailer, nearside, so that you are close to what you are levelling up to. Although we did have one that had it on the headboard as I remember 
I’ve also seen them on the opposite side so might be best to have a good look round the trailer. As said above, these look more like brake buttons.
I’m sure the OP knows what a leveling lever looks like… just as he doesn’t need me to suggest following the airlines from the airbags 
the nodding donkey:
I’m sure the OP knows what a leveling lever looks like… just as he doesn’t need me to suggest following the airlines from the airbags
Yes i know what a leveling lever looks like … & there isn’t one!!
The red control is the parking brake, the right hand blue control seems to bleed air from the system but that doesn’t effect the ride height so I guess it’s only from the brakes. The blue central button doesn’t want to move at all so maybe it’s a defective unit to control the ride height but otherwise I’m out of ideas as to what it might be? … Surely no one makes a trailer on air without being able to change the trailer height when you need to?
Diggerlot:
the nodding donkey:
I’m sure the OP knows what a leveling lever looks like… just as he doesn’t need me to suggest following the airlines from the airbagsYes i know what a leveling lever looks like … & there isn’t one!!
The red control is the parking brake, the right hand blue control seems to bleed air from the system but that doesn’t effect the ride height so I guess it’s only from the brakes. The blue central button doesn’t want to move at all so maybe it’s a defective unit to control the ride height but otherwise I’m out of ideas as to what it might be? … Surely no one makes a trailer on air without being able to change the trailer height when you need to?
Yes, there are trailers on air you cannot change the ride height on and are just built without the colas valve - usual handle.
Own Account Driver:
Diggerlot:
the nodding donkey:
I’m sure the OP knows what a leveling lever looks like… just as he doesn’t need me to suggest following the airlines from the airbagsYes i know what a leveling lever looks like … & there isn’t one!!
The red control is the parking brake, the right hand blue control seems to bleed air from the system but that doesn’t effect the ride height so I guess it’s only from the brakes. The blue central button doesn’t want to move at all so maybe it’s a defective unit to control the ride height but otherwise I’m out of ideas as to what it might be? … Surely no one makes a trailer on air without being able to change the trailer height when you need to?Yes, there are trailers on air you cannot change the ride height on and are just built without the colas valve - usual handle.
…OK thanks, so is it relatively simple to retro fit a colas valve to allow the ride height to be lowered for loading?
Had an air ride trailer years ago that management had removed the handle from so the raise lower couldn’t be used ( god knows why ) so all you had was a square ended head for the mole grips to fit on - have a look for that.
Reasonably certain that the centre button in the picture is for a lift axle.
Diggerlot:
…OK thanks, so is it relatively simple to retro fit a colas valve to allow the ride height to be lowered for loading?
We transferred one from a scrap trailer to one of ours that did not have one and it was fairly straightforward, found the correct diagram on the haldex / colas site (assume you would get this if you bought a new one anyway) and the ports on the valve are numbered to correspond. Essentially all you are doing is interrupting the supply to the bags and also there is the option to plumb in the auto raise when you move away but we did not do that as it was an old trailer (just cleans the inside of the mudwings if you forget 
. ) This was all on relatively old trailers so not sure if there are other things to consider on newer gear.
