Can anyone explain in simple terms why the yellow air lead should always be put on first and taken off last? Is it that important?
Just do left to right myself cos it’s the easiest way suppose right to left if your left handed 
Red is emergency line and the brakes won’t release until that is on.
It really doesn’t matter. I do the leads in a different order depending on whether it is a left or right hand catwalk and depending on the trailer. I do furthest to nearest when coupling, nearest to furthest when uncoupling.
There was a long thread about this a while back, I’ll see if I can find it.
i was taught to put the leads on furthest away from you,then take them off nearest to you,so make things a bit eaiser so your not getting tangled up in them.
never heard anything about taking off the yellow line first…
no, its up to you to establish your own system, and stick to it, regimently.
as long as youre not one of these morons who changes trailers without putting the unit park brake on, you wont have a problem
I can never understand why there isn’t a standard positioning for air leads and electricals on trailers which matches the position on units, so you have half a chance of not getting them tangled up.
Coffeeholic:
It really doesn’t matter. I do the leads in a different order depending on whether it is a left or right hand catwalk and depending on the trailer. I do furthest to nearest when coupling, nearest to furthest when uncoupling.There was a long thread about this a while back, I’ll see if I can find it.
I do the same.
@ Banquo, basically do it in the order that has the least chance of you getting [zb]ed up with grease. 
The only reason is to do the one furthest away from you first when coupling, or last when uncoupling, is because the steps are normally at the drivers side 
(if fitted). When I had a left ■■■■■■ I used to do the red line first, just to keep clean.
Not technical or safety reasons, just common sense 
Is it not red on first and off last as red is the emergency line and yellow is the service line? Say for instance the shunt button is on and park brake off and you’ve not hooked up properly over the pin etc you stick the yellow on is there not a possibility you could be crushed between trailer and unit?
I put on yellow first purely for the fact it can be a bugger at times and my knee is sometimes required.
Wheel Nut:
The only reason is to do the one furthest away from you first when coupling, or last when uncoupling, is because the steps are normally at the drivers side (if fitted). When I had a left ■■■■■■ I used to do the red line first, just to keep clean.Not technical or safety reasons, just common sense
Shows how long it is since you’ve driven a wagon Malc. I know Renault, Volvo and Stralis are all accessed on pax side and there are probably other marques as well but can’t think off top of my head.
Wheel Nut:
The only reason is to do the one furthest away from you first when coupling, or last when uncoupling, is because the steps are normally at the drivers sideNot technical or safety reasons, just common sense
At our place, all RHD, we have Volvos, Mercs and Renaults with catwalk steps on the passenger side and DAF’s and MAN’s with them on the driver’s side.
Coffeeholic:
It really doesn’t matter. I do the leads in a different order depending on whether it is a left or right hand catwalk and depending on the trailer. I do furthest to nearest when coupling, nearest to furthest when uncoupling.There was a long thread about this a while back, I’ll see if I can find it.
I do the same its gotta be the easiest way its better than reaching over leads and getting grease on your strides.
Couldn’t find the old thread but this is how the H&S folks say it should be done.
hse.gov.uk/workplacetranspor … upling.htm
They have red last on coupling and no order for uncoupling but their reason for doing the red last can happen whether you do it first, last or whenever and they do like to make things up to try to justify their jobs.
I put the ABS lead in first sometimes, is that ok or do I risk blowing up the trailer?
bubsy06:
I put the ABS lead in first sometimes, is that ok or do I risk blowing up the trailer?
no,you’ll just blow up the flux capacitor!!! 
merc0447:
Is it not red on first and off last as red is the emergency line and yellow is the service line? Say for instance the shunt button is on and park brake off and you’ve not hooked up properly over the pin etc you stick the yellow on is there not a possibility you could be crushed between trailer and unit?
I put on yellow first purely for the fact it can be a bugger at times and my knee is sometimes required.
If the shunt button and trailer brake buttons are both in ( and the trailer air is up), the trailer is free to roll wherever is it pushed.
It should never be in this state unless firmly attached to a tractor unit.
If the unit applies the trailer brake with its handbrake, connecting the yellow line will apply the trailer brakes whether the shunt button is out or not.
If, like a Volvo or Scania, the unit handbrake does not apply the trailer brake, connecting the yellow line will have no effect.
Connecting the red line will push the shunt button out and if the driver has been stupid or careless enough to leave both the trailer brake and tractor handbrake off, then the combination is free to roll away with probably tragic results.
In my opinion, no driver should even consider stepping onto the catwalk until he is quite sure that both brakes are applied.
After that, it doesn’t matter which line or lead is connected first or last.
Regards,
Nick.
bubsy06:
I put the ABS lead in first sometimes, is that ok or do I risk blowing up the trailer?
You might, but best to put the ABS in with the engine and ignition off. Reduces the number of ABS amber warnings that way.
Rob K:
Wheel Nut:
The only reason is to do the one furthest away from you first when coupling, or last when uncoupling, is because the steps are normally at the drivers side (if fitted). When I had a left ■■■■■■ I used to do the red line first, just to keep clean.Not technical or safety reasons, just common sense
Shows how long it is since you’ve driven a wagon Malc. I know Renault, Volvo and Stralis are all accessed on pax side and there are probably other marques as well but can’t think off top of my head.
The wink about the steps was intentional Rob.
My right hand drive Volvo had left handed steps.
My left hand drive MAN had right handed steps
My left hand drive Volvo had left handed steps
I cant remember any other lorries having steps
Surely the company who is buying can spec what ever side they want?