A spare yellow airline

scaniason · 31 May 2012 08:07

Time for another post from me asking a noddy question…

I passed a Prologic lorry pulling a skelly & box on the M25 yesterday, and noticed that he had a yellow airline, with what appeared to be a palm coupling on it, sitting in the park holder on the back of the unit, as well as a full set of lines going to the trailer (as you’d hope ). Anybody know what the other yellow line would be for? I wondered if if might be for pulling continental trailers, but wouldn’t it be easier to carry a set of adaptors, and also wouldn’t there be a red one as well if this was the case?

Gary

harry_monk · 31 May 2012 08:18

At a complete guess, I’m going to say he uses it to alter the length of the skelly.

shropsbri · 31 May 2012 13:24

Or it’s the cherry line.

harry_monk · 31 May 2012 13:52

ShropsBri:
Or it’s the cherry line.

If it wasn’t a skelly I would have said the same.

bigfoot · 31 May 2012 17:29

whats a cherry line

Harry, how could that air line be used to alter the length?

Thanks.
Ben

harry_monk · 31 May 2012 17:40

bigfoot:
whats a cherry line

In ye olden days, owner-drivers often had a secret compartment built into the headboard of the trailer containing red diesel (cherry), and this would be fed directly to the engine using a dummy airline. Highly illegal of course.

bigfoot:
Harry, how could that air line be used to alter the length?

You’ll have seen that skellies can be altered in length. The way you normally do this is to disconnect the red airline, and connect that to a different but identically sized male coupling on the front of the skelly. The air pressure withdraws the locking pins from the chassis, meaning that you can lengthen or shorten the trailer by moving the tractor unit forwards or backwards. When you get to the new length and remove the red airline, the locking pins shoot out again through different holes in the chassis, locking it at its new length. You then re-connect the red airline to the normal coupling and off you go. Possibly this is a slightly modified version of that, to save removing the red airline, but this is only a guess.

wheel_nut · 1 June 2012 00:23

Harry Monk:
You’ll have seen that skellies can be altered in length. The way you normally do this is to disconnect the red airline, and connect that to a different but identically sized male coupling on the front of the skelly. The air pressure withdraws the locking pins from the chassis, meaning that you can lengthen or shorten the trailer by moving the tractor unit forwards or backwards. When you get to the new length and remove the red airline, the locking pins shoot out again through different holes in the chassis, locking it at its new length. You then re-connect the red airline to the normal coupling and off you go. Possibly this is a slightly modified version of that, to save removing the red airline, but this is only a guess.

I would go along with that, probably to prevent the wrath of God or H&S and prevent the driver climbing on the catwalk. Without a helicopter with a searchlight and a secure harness, that is now deemed too dangerous for a stupid lorry driver

sam_millar · 1 June 2012 20:37

Harry Monk:

bigfoot:
whats a cherry line

In ye olden days, owner-drivers often had a secret compartment built into the headboard of the trailer containing red diesel (cherry), and this would be fed directly to the engine using a dummy airline. Highly illegal of course.

bigfoot:
Harry, how could that air line be used to alter the length?

You’ll have seen that skellies can be altered in length. The way you normally do this is to disconnect the red airline, and connect that to a different but identically sized male coupling on the front of the skelly. The air pressure withdraws the locking pins from the chassis, meaning that you can lengthen or shorten the trailer by moving the tractor unit forwards or backwards. When you get to the new length and remove the red airline, the locking pins shoot out again through different holes in the chassis, locking it at its new length. You then re-connect the red airline to the normal coupling and off you go. Possibly this is a slightly modified version of that, to save removing the red airline, but this is only a guess.

I’m going to ask a stupid question also and that’s how do you reduce the length of the skelly because I sure as hell can’t imagine parking up in front of a brick wall and reversing into it gently hahaha

harry_monk · 1 June 2012 20:55

Sam Millar:
I’m going to ask a stupid question also and that’s how do you reduce the length of the skelly because I sure as hell can’t imagine parking up in front of a brick wall and reversing into it gently hahaha

No such thing as a stupid question, only a stupid answer, as I say time and time again.

To shorten a skelly, you remove the red airline. This immediately locks the trailer brakes on.

Then you connect the red airline to the auxiliary male coupling. This releases the locking pins.

Then you get back into the tractor unit and drive slowly forwards or backwards. The trailer brakes are locked on, and the trailer is like a trombone, one part of it slides against the other. So it shortens or lengthens.

Then you remove the red airline from the auxiliary male coupling. The locking pins move back into place. You reconnect the red airline to the main coupling, the brakes release and off you go.