Intro to coupling exercise- C+E (artics) WITH PICS

This post is designed to be an introduction to the coupling exercise and is written in a deliberately non-technical way. It relates to C+E artics.
I’m aiming at giving you a head-start with terminology and some pics of the items.
There’s no attempt at describing the exact procedure, because ROG has covered that in the next post below this.

(It’s a l…o…n…g post, so grab a butty and you’ll need to scroll… )

The tractor unit in the pics is an “S” registered Volvo FL10 as used by many LGV training schools.

The pic below is of a fairly common type of fifth-wheel known as a “slider.”
The non-sliding type wouldn’t have the shorter of the two handles, because that kind of fifth-wheel is “fixed.”
I’m not covering the sliding of it, because it might cause confusion.
The one thing I’ll say about sliding these is that it should only be carried out by an “old hand,” because if you get it wrong, the potential damage could be very expensive to put right.

PIC 1

The big greasy plate is the “fifth-wheel” (this one needs more grease!!) The fifth-wheel supports the weight of the front end of the trailer and has a locking mechanism for grabbing the trailer’s “king-pin” just visible at the bottom of the “V” shaped notch in the above pic. To uncouple the trailer you stand on the driver’s side of the truck and, after removing the safety-clip, pull the longer of the two handles towards you. After the landing legs have been lowered, the action of pulling out the handle about 2’ (like in the pic) “opens” the coupling and you can then drop-off the trailer.

PIC 2

You can see the locking mechanism much more clearly in this pic.

The locking mechanism grabs the trailer’s “king-pin.”
The king-pin is in the centre of the pic below.
PIC 3

It’s very important to make sure that the heights of the fifth-wheel and kingpin are correct, because if the trailer was dropped-off by a higher tractor unit you’d miss the pin completely and smash the back of your cab with the front of the trailer. (It has been known to happen… ) When you’ve checked the heights (from outside the cab,) you reverse gently under the trailer until you hear a clunk. You then do a couple of “test-pulls” to make sure that you have “grabbed” the king-pin correctly. If you look at it again from outside the cab, you’ll notice that the lock release handle (the longer of the two in the first pic,) is now much shorter, because the coupling has closed AND locked. That’s what makes the (loud) clunk noise. We can say that the closing and locking of the coupling is automatic, once you’ve reversed far enough.

That just leaves the air and electrical “susies” so here’s a few pics of those.
They don’t need much explanation, because they have different ends/connectors, so you can’t really make any mistakes with these.
I’ll just stick with what we call them.

PIC 4
Red air line.

PIC 5
Yellow air line.

PIC 6
3 x Electric “susies” (Various sized/coloured ends with different connectors.)

Your instructor will give you as much detail and explanations as you you’ll need for your test.
I avoided trying to describe the exact procedure so as to leave you with a head start rather than a spinning head.
I hope there’s a bit less mystery to the words we use and what the things look like. Like my post about the gearboxes, could you please leave a bit of feedback so I know whether I’ve got this right- CHEERS.
I hope you find it helpful.
GOOD LUCK with the driving tests.!!!

PROCEDURE WITH PICS
Video of LEG WINDING & Other useful things
COUPLING UP - When Trailers Bite Back

ARTIC UN/COUPLE PROCEDURE for the DSA test.

Included are references to the pics in Dieseldave’s post above
The usual time to do this is after the road drive and on the reversing area — the examiner will inform you where to park and you will stop in a straight line. A lot [of test candidates] ask the examiner if whether they have passed at this point because they feel that doing the un-couple & couple-up procedure is just wasting time if they have already failed — this is acceptable to the examiner.
Not every instructor teaches this exactly the same way but there will not be much difference. For ease, I have divided this into three stages. 1, the uncouple, 2, the trailer check and 3, the couple up. I always get my trainees to do a complete circuit of the lorry.

Stage one — the uncouple.
Switch off engine and exit cab with the keys and some gloves.
The word is B.L.A.C.K.
B = brake
L = legs
A = airlines (and electrics)
C = clip
K = kingpin (coupling locking device)

Mothertrucker:
Good one - although I always use BLANK
Brake
Legs
Airlines
Number plate
Kingpin (which includes clip)

Apply trailer (B)rake. There are usually two pull devices and only one is the brake — the other is the shunt. Your instructor will show you, which is which as not all are set up the same or located in the same place on each trailer.
Wind down the (L)egs until the lowest leg touches the floor and then do one wind back with the handle and stow it in the holder. This prevents a big BANG as you pull the unit out and on the couple up, if the unit is not perfectly lined up with the trailer, it lets the trailer “float” so the legs do not gouge the floor — the DSA do not like their reverse area having chunks of tarmac missing!
There are two aspects to the winding handle set up, the spigot and the handle. The spigot has 3 settings. Pulled fully out for normal windup & down, pushed fully in for super slow wind up & down and the middle of the two, which does nothing. The winding handle is used to pull or push the spigot. So, for normal winding down of the legs, pull the spigot fully out with the handle and then gently slide the handle back in along the spigot without pushing the spigot back in — this will now allow you to wind down the legs with one hand as the handle is locked along the spigot.
Now the (A)irlines & electric connections need to be detached from the trailer and properly stowed onto the holders on the back of the unit. On my set up there are 2 airlines and 3 electric ones. The red airline (see pic 4) is detached by turning the collar until the groove in it lines up with the little spigot, then pull the collar so the groove slots into the spigot and the red line will now release. The yellow airline (see pic 5) also has a collar and a groove, which will line up with a spigot, but this time the collar is pushed into the spigot to release it.
Two of the electric lines just pull out but the ABS electric line has a ‘trigger’ to pull underneath it (see pic 6) so it can release — this ‘trigger’ needs to be pushed forward to connect it properly onto the housing for it on the back of the unit.
Most units have steps to get up onto the back of the unit — use them and get down the same way — do not jump off — it’s very hard to carry on with a twisted ankle or worse!
At this point, all the work has been done on the nearside of the set up I use, so I now get the trainee to walk around the back of the trailer to get to the clip. Whilst passing the rear, they say, “remove number plate” to the examiner.
The (C)lip is a safety device that stops the kingpin handle from being pulled out. This is the bit where you usually get muck & grease etc on you!
Reach under the body of the trailer, above the rear unit axle and squeeze the lower part of the clip so that the top bit can be pushed up and out of the hole that it is slotted into. If you have a place to stow the clip, which is usually on a chain attached to the unit, then do so — it makes it easier to find on the couple up.
The (K)ingpin handle is now ready to be pulled out and is done by pulling it slightly forward and then fully out (two hands if struggling) with a slight back pull to lock it out. Do not mix up the kingpin handle with the plate slider handle (see pic 1) if your set up has one — your instructor will show you which is which.
Get back into the cab and engage a low gear to pull the unit from under the trailer, taking care not to drop the trailer the last inch, due to the legs not quite touching the floor, when the fifth wheel plate tilts up from the front of the trailer body.
Park the unit parallel to the side of the trailer, facing forward — the examiner might tell you which side to put it.

Stage two — the trailer check.
The examiner will ask you to pick up the trailer and to pretend that you have never seen this trailer before.
Get out of cab with keys and gloves.
Do a complete trailer check, just like the one you did before setting out in the morning, body, reflectors, doors, tyres, nuts etc, etc, with the addition of the fifth wheel pin check (see pic 3) as they may be a pin lock on it or something might be wrapped around it . Is the trailer MOT in date? Are the connectors for the air and electric lines damaged? On the walk around trailer check, tell the examiner what you are looking at, or touch (hence the gloves) all the areas that you are checking. That way, the examiner can see what you have checked.
MAKE SURE THE EXAMINER SEES YOU CHECK THE TRAILER BRAKE IS ON BY GIVING THE BUTTON A PULL.
Now, get back into the unit and whilst going forward in front of the trailer line up using both mirrors. Reverse towards the front of the trailer using both mirrors to line it up ( you should be able to see the same amount of trailer in each mirror as you do so ) and stop as close as possible without going underneath. Leaving the engine running (seems to be the accepted practice at this point as it is only going to be for a moment) get out of the cab and check that the fifth wheel plate will go just under the trailer (I get my trainees to do this with a flat hand, palm down gesture) and then lightly touch the fifth wheel handle to show that you know it is still out (has been known for some to spring back in!), then get back into the cab and proceed to reverse under the trailer.
You will feel and hear the locking of the unit to the trailer but to check that it is locked, engage a low forward gear and gently try TWICE to pull out.
Apply handbrake.

Stage three — the couple up.
Get out of cab with keys and gloves.
The word is K.C.A.L.B. (BLACK backwards) The (K)ingpin is already sorted — that locked in at the end of stage two.
Put the (C)lip back into the hole you took it out of on the uncouple.
Attach the (A)irlines and electrical connections. They are designed to fit only in their designated slots — you cannot fit them into the wrong one. The red airline is the hard one as there is air pressure to push against — a lot of trainees get their bum against the rear of the unit for extra leverage. The collars and pins of the airlines have to be lined up and slotted in for the airlines to fit onto their respective housings. Once connected, give the collars a twist for safety, so they are not left in line with the pins.
Wind up the (L)egs and stow the handle.
Release the trailer (B)rake.
Walk to the rear of the trailer and say to the examiner “number plate on and please would you check my trailer lights.”
Calmly, and whilst walking slowly back to your cab, check that you have done everything— Kingpin, Clip, Airlines etc, Legs, Brake & number plate■■?
Start engine, switch on dipped headlights and rear foglight(s) then do a separate indicator check (not hazards) and finishing with brake lights. Then, switch off all lights and the vehicle engine, and wait for the examiner to get back into the cab with you, where you will hear those nice words “I am happy to tell you that you have passed.”

Hiya bud,
A really good, clear and understandable explanation.
I just wish it was posted before i did my test…although it didn’t cause me any major problems, i feel a good post like this would’ve helped.
Cheers
Steve

Helps a lot
Any chance of a pic of the landing legs and how they work?

ROG:
a word I use - BLACK

To uncouple-
Brake
Legs
Airlines
Clip
Kingpin

To couple- (BLACK reversed)
Kingpin
Clip
Airlines
Legs
Brake

That’s a great point ROG, but I deliberately stayed away from the exact procedure, in favour of helping out with strange-sounding words supported by a few pics. I thought it might aid your “tips” post with some pics and jargon busting.

Cheers Dave!!

CaPo:
Helps a lot
Any chance of a pic of the landing legs and how they work?

HI CaPo and WELCOME.

Sure thing about the landing legs- I’ll see what’s in the yard tomorrow.

I’ll post a pic or two if I can get near a trailer.
I don’t think it’s worth a post on its own, but I can certainly add it to the post you’ve already seen.

Watch this space…

Very informative DieselDave,

I wish this had been on when I was doing my training.

One question though, what is the 3rd electrical cable for ?

I learnt on a V reg Volvo FM12 which only had 2 cables, also when working for Spar last week (my first job), the vehicle they gave me also only had 2 electrical cables.

Ian.

ianf6512:
Very informative DieselDave,

I wish this had been on when I was doing my training.

One question though, what is the 3rd electrical cable for ?

I learnt on a V reg Volvo FM12 which only had 2 cables, also when working for Spar last week (my first job), the vehicle they gave me also only had 2 electrical cables.

Ian.

Third one is usually ABS or EBS. If it is fitted it must be used, if not fitted you can’t

Aye, but all test vehicles have to be fitted with ABS and it must be working (except B+E Car with Trailer tests).

I read the DSA’s DT1 form that examiners use for telling them how to conduct tests and I noticed another section to the Minimum Test Vehicle requirements - RTM (Real Total Mass). I take it that means that LGV tests (from 2010) will need to have ballast in the cargo area to make the test more realistic? If that’s the case then I’ll be very pleased, driving unladen is completely different to when you actually have cargo aboard! Being a bus driver I can Certainly say that when you have 90 people aboard your double decker vehicle (78 seating + 12 standing, which is legal!) you have to drive completely differently!

Richard

CaPo:
Helps a lot
Any chance of a pic of the landing legs and how they work?

this is a pic of how they shouldnt look

that handle should be attached. wind it anti clockwise to lift the legs (all the way up then back half a turn) or clockwise to lower the legs

the handle has 3 positions. push it right in to lower slowly (handy if its too high for the unit), pull back one notch to disconnect it for stowing and pull it right out for normal winding
the will be a bit of metal hanging off the housing. when you are not winding the legs, the handle stows in that to prevent it swinging around

Guys,
In the picture of the electrical suzies, what is the one with the locking lever on the plug for ?
I had a unit yesterday with this cable but no socket on the trailer for it to plug into. I just plugged in the other two + airlines.
Is it when the trailer has ABS & I assume my trailer didn’t have ABS ? It was a old trailer, by the state it was in.

Whoops the question has already been answered further up the thread…

gerontius:
Is it when the trailer has ABS & I assume my trailer didn’t have ABS ? It was a old trailer, by the state it was in.

Without looking up the original VOSA press release from when the connection of these cables became a requirement, IIRC it mentioned something along the lines of “where the ABS does not draw its power from an auxiliary lead…”

So, although the trailer was not fitted with a socket for - what I tend to refer to as a ‘Data lead’, it may still have working ABS powered from a different source, i.e., the Aux lead.

Even where a socket is fitted, there may also be a mis-match on the number of pins. Again working from memory, it is usually 7, but there is another variation with something like 12 pins.

No doubt someone will soon be along with the correct numbers.

Hi Diesel Dave,

What a great set of photos and it’s very well written too. You have helped me no end there, you answered all the questions that i asked about and more besides. It will give me more confidence if i am asked on friday to uncouple.
Many thanks

Pan man

something ive learned pretty quickly is if youre dropping an empty trailer, just wind down the legs until they hit the ground, dont start winding them any further, you need the trailer to dip a little bit when you come out from under it

and obviously if youre dropping a loaded trailer wind those suckers down LOTS

beattun:
something ive learned pretty quickly is if youre dropping an empty trailer, just wind down the legs until they hit the ground, dont start winding them any further, you need the trailer to dip a little bit when you come out from under it

ROG:
for the DSA test in an empty trailer
Wind down the (L)egs until the lowest leg touches the floor and then do one wind back with the handle and stow it in the holder. This prevents a big BANG as you pull the unit out and on the couple up, if the unit is not perfectly lined up with the trailer, it lets the trailer “float” so the legs do not gouge the floor — the DSA do not like their reverse area having chunks of tarmac missing!

beattun:
and obviously if youre dropping a loaded trailer wind those suckers down LOTS

Great advice for after the test

i learned that one all by myself!

with 24 tonne of sugar on the trailer

Stage one — the uncouple.
Switch off engine and exit cab with the keys and some gloves.
The word is B.L.A.C.K.
B = brake
L = legs
A = airlines (and electrics)
C = clip
K = kingpin (coupling locking device

Good one - although I always use BLANK
Brake
Legs
Airlines
Number plate
Kingpin (which includes clip)

Mothertrucker:

Stage one — the uncouple.
Switch off engine and exit cab with the keys and some gloves.
The word is B.L.A.C.K.
B = brake
L = legs
A = airlines (and electrics)
C = clip
K = kingpin (coupling locking device

Good one - although I always use BLANK
Brake
Legs
Airlines
Number plate
Kingpin (which includes clip)

I did consider a mis-spelling BLANCK

so thats how its done I wish all this info was about when i took my test back in the black and white days althou i did have power steering in the truck i sat my test in