So to describe breifly my procedure… line up with trailor loewer susspention go under it till 5th wheel is under the trailor but infront of the pin hook up airlines etc raise susspention till legs off floor reverse back to pick up the pin.
I have done this procedure every time i pick up a trailer always there are 2 bangs as i reverse back i assume the back of the jaw hitting the pin and the bar/mechnisum sliding across. Last night i only got 1 dull thud tried a tug test and it hadnt connected got out checked everything was correct ie arm in the right place etc and tried again. Still 1 dull thud but this time the first tug was ok but on the second a loud bang and unit shot fwd without the trailer. Went and got help as i havent a clue what i am looking at all checked out ok tried a third time with the same result as the first. 4th time i came back still a dull thud but the guy wiggled the arm and on tug test all was fine and checked the bar was across and clip in. all ok on the road
drop that trailer at the destination again 1 dull thud but it had picked the pin up as i gave it three good tug tests bar across and clip in. However every time i slowed down or accelerated away there was a loud bang and a jerk. even trying to do it gently didnt seem to make much difference. Once i was unloaded it was eveb worse.
The only different thing to the normal as it were is i was in a strange truck and both times the trailer was sitting a lot further back ( father christmas could have a barn dance with 20 of his mates on the cat walk with the trailor connected as aposed to me ay 9 stone went just about squeexing between the fridge and back of the cab
I think the important thing is that you have done up the dog clip.That covers you.
If you get out and push the handle in,just push it to the left,it will spring into place,apply the dog clip,do your two tugs.If youve done all that and the trailer drops off the back,you are covered.You have done everything properly.By the way,check the trailer brake is one before you hitch up
Sounds like the fifth wheel mechanism is worn and needs adjustment or replacing…edit md beat me to it.
If you hook up and leave the trailer brake applied if you get an assistant to have alook see whilst you attempt to pull forward and go back again they (or you if you get someone else to jump in the cab) will probably see the rubbing plate slide over the fifth wheel showing wear in the mechanism.
When they get really worn as you go from under power to overrun you’ll feel the rear of the tractor twitch slightly sideways, i’ve also had this effect on a tractor where the drive axle control arm bushes were badly worn one side, this in effect was causing the drive axle to move out of line depending on being under power or on overrun, this was a supermarket motor with seriously worn out bushes they didnt get like that in 5 minutes but seemingly no bugger elese had the foggiest summat was up
Another possibility is either trailer or tractor on the ■■■■ when you go to pick it up, this is where things can get dicey because its possible for the mechanism to lock home and fit the dog clip yet the king pin is sitting on the jaws not tucked nicely inside, if in doubt have a look up the fifth wheel’s skirt with a torch to note the bar is fully home across the pin, and if in doubt pull the connected outfit onto flat ground and again have a look, if its on the jaws then there should be a small gap visible between fifth wheel and rubbing plate.
I’ve had this happen myself many years ago, that could easily have ended in disaster but as yourself something didn’t sound right at pick up so paid extra attention and pulled it down onto the flat ground.
Anyone here actually had a trailer detach?
My Dad was dismissed many years ago from McKeefry for dropping one of their tanks. Not sure if that was intentional though lol.
Other was when I worked at Daf in Trafford Park, the driver of the BBC Proms truck picked it up in the morning after service. The mechanic had slid the unit under the trailer but it obviously wasn’t coupled. Driver connected lines and wound up legs. Away he went and turned towards the gate… BANG.
As well as the excellent advice above, you will also find on occasions that you can ’ over lift ’ the trailer. I have had the ’ dull thud ’ on a few occasions and as mentioned above it is usually work mechanisms. However, I have driven numerous brand new tractor’s over the years and the odd one now & again need a bit of bedding in.
Regarding the over lifting comment I proved my own theory on one occasion by trying differing unit heights whilst hooking up to a particular trailer. At full height it really didn’t like it and I had to move the handle to the left but with the legs only a few inches off the ground I got the familiar ’ click '. The purpose of lifting the trailer is simply to ensure you don’t miss the pin and you can wind the legs, not to create a ski slope. I watch with sadness as some bellend’s rev the crap out of their units and seem determined to gain every available mm of height possible. I watch with equal sadness the moron’s who do five tug tests with the legs on the deck trying to make them look like banana’s that can never be fully wound up ever again The agonising groaning sound can be heard 3 postcode’s away ffs…
(Obviously my over lift exercise was carried out to satisfy my own curiosity and was also rightly done on agency overtime rate whilst dragging the job out).
md1987:
Anyone here actually had a trailer detach?
My Dad was dismissed many years ago from McKeefry for dropping one of their tanks. Not sure if that was intentional though lol.
Other was when I worked at Daf in Trafford Park, the driver of the BBC Proms truck picked it up in the morning after service. The mechanic had slid the unit under the trailer but it obviously wasn’t coupled. Driver connected lines and wound up legs. Away he went and turned towards the gate… BANG.
Years ago one of my colleagues from another depot ran all the way from Wales and dropped the empty curtain sider on the embankment probably on the bad undulations near Battersea bridge, none of us could work out what had happened until the event i decribe above which happened a few months later.
md1987:
Anyone here actually had a trailer detach?
My Dad was dismissed many years ago from McKeefry for dropping one of their tanks. Not sure if that was intentional though lol.
Other was when I worked at Daf in Trafford Park, the driver of the BBC Proms truck picked it up in the morning after service. The mechanic had slid the unit under the trailer but it obviously wasn’t coupled. Driver connected lines and wound up legs. Away he went and turned towards the gate… BANG.
Years ago one of my colleagues from another depot ran all the way from Wales and dropped the empty curtain sider on the embankment probably on the bad undulations near Battersea bridge, none of us could work out what had happened until the event i decribe above which happened a few months later.
cooper1203:
So to describe breifly my procedure… line up with trailor loewer susspention go under it till 5th wheel is under the trailor but infront of the pin hook up airlines etc raise susspention till legs off floor reverse back to pick up the pin.
NOOOOOOOOOOOOOOO. Who the hell taught you that way to hook up a trailer? If you want to have one go sliding off the back of the unit and end up on it’s knees as soon as you put the red line on, because not all trailers have automatic park brakes and shunters along with lazy drivers are notorious for not putting the park brake on, then this is the way to hook a trailer up. No bloody way should you be doing that, putting airlines on and winding legs up before you know the pin is locked in. You should be locking it into the fifth wheel and doing the tug test before you even consider doing anything else, putting any air lines on. Even if you’re doing split coupling don’t wind up the legs until you’ve locked it in the fifth wheel and done your tug test. .
Conor assumes that no one but himself checks the handbrake first.
He also didn’t bother to read the post carefully before he weighed in with the bit about winding the legs up. Where did the OP day he winds the legs up before he’s properly coupled up?
Clue He didn’t.
Conor assumes that no one but himself checks the handbrake first.
Quite a few don’t, they assume that the park brake automatically comes on or they don’t bother because they’ve put the unit part brake on, or at least they think they did.
Just remembered an interesting one from my brief agency stints.
Similar to Coop’s experience attempting to hook up and it just wouldn’t engage, pulled the tractor out for a look see and noticed the fifth wheel pull arm looked out of place, it appeared when the last driver dropped a trailer maybe dropping too low or something sticking out, but as they pulled out the pull arm was bent backwards, confirmed this by trying to knock it back as mentioned above (which you sometimes need to do) it couldn’t be done.
Straight away i’m going to be in the frame for this (obnoxious bloody people there, can’t keep full time staff treat 'em like skivvies) but luckily out of sight of the main yard, scouted round and found a bar and after considerable effort bent the thing back into shape.
Coop, have a play with the next tractor you use, whilst disconnected pull the handle again and see how you can pull it so far it locks on that cut out and then knock it back so it slots in when you hook up, note also that before you hook up there’s a nice fully open run for the king pin to slot in.
Like a lot of these things you don’t take too much notice of how they work until it suddenly doesn’t, then you’re unfamiliar with how it all should be.
One other thing, question for ‘drivers’ generally, why are you so afraid of a bit of grease, is the fifth wheel dry with shiny surfaces where its metal to metal contact, this makes for a most uncomfortable drive and i’ve actually heard screeching from turntables before so bone dry have they been, if it runs dry between inspections either put some grease on it if you work for a proper company who keeps such essentials or defect it and run it into the workshops so someone can…and don’t do a CF and wipe all that new grease up the front of the rubbing plate when you next connect up
Conor assumes that no one but himself checks the handbrake first.
He also didn’t bother to read the post carefully before he weighed in with the bit about winding the legs up. Where did the OP day he winds the legs up before he’s properly coupled up?
Clue He didn’t.
i also said it was a brief description ie not everything i do.
to put the mind at rest depending where the trailor is i will either walk over to it and do my checks or line my self up infront of it if i wont be in anyones way these checks include putting the park brake on checking things like tyres body work damage lights security of trim.
whilst doing these checks i also breath in and out at regular intervalsand should the need arise if my arse itches ill scratch it.
thnks for the replies but of an update its not clear why i had an issue hooking up. However i have since discovered that there is an issue with the 5th wheel as suggested. vehicle is now off road and is due to be repaired today apparently.
md1987:
Anyone here actually had a trailer detach?
I was doing a trailer swap in the evening at a small place near Evesham. I dragged the loaded trailer off the bay and dropped the empty one in its place. Then I backed under the loaded trailer, took the weight on the fifth wheel (split coupling due to the close-coupled fridge) and hooked up the lines (yes I had put the trailer brake on).
At that point, the warehouse guy came out with the paperwork and “helped” by winding the legs up. We had a bit of a chat and I jumped in and started to pull away. I felt it slip and hit the brake just in time to stop it from falling off the rails. Lesson learned - if you get interrupted, take a step back and think it through.
While I was working at Blake’s, one of their shunters pulled a [very] heavy trailer loaded with cheese off a bay, round the yard and backed it into a parking space. He did one shunt to get it straight and it fell off. The pin had been resting on top and not in the jaws.
