switchlogic:
Christ, American trucks really are made of cardboard aren’t they?!
The result of trying to provide for a viable payload within a silly gross weight regime.A bit like plastic cabbed Brits running at 32t gross.
Juddian:
dave docwra:
In almost 46 years I have never seen a jaw failure, I have seen fifth wheels ripped from the chassis & I have only ever seen one king pin sheared, has anyone else apart from nick2008 seen a fifth wheel with jaw failure and if so how did it fail?Nope, me neither, seen overshoots, seen trailers dropped on their knees, known trailers to bounce off having been sat on the jaws, actually had a kin pin sitting on the jaws (sorted immediately never took it on the road), had worn fifth wheels which i’ve defected, but never, and 4 decades too, known of a fifth wheel actually failing.
I watched, amazed, a shunter at Castrol reversing flat out under trailers with a Big J hitting the pin with a deafening bang, even that abuse didn’t break either a pin or fifth wheel.
Worked for W Smith and sons (Hanham ) ltd in Bristol we had a big D 5th wheel jaws come apart 30 yrs ago driver was Gordon Vickery he had the same trailer on all week never dropped it Even in the yard.
He lost the trailer on the little roundabout just down from the maypole pub the roundabout is on a twist. Vosa and plod were called out we walked the whole way from the accident back to the yard and didn’t find anything but the jaw plate and nuts were missing. and just recently we’ve had some issues with wrong 5th wheels fitted to Mercs.
Also if the slack adjustment is not done correctly that’ll cause problems
Funnily enough it was a BigD that locked home with the pin sitting on the jaws (to be fair the trailer had been dropped empty on the ■■■■ for loading, heavy too so had to force the fifth wheel under), and the same make fifth wheel that our colleague lost the trailer from after some 120 miles empty motorway running.
Juddian:
Funnily enough it was a BigD that locked home with the pin sitting on the jaws (to be fair the trailer had been dropped empty on the ■■■■ for loading, heavy too so had to force the fifth wheel under), and the same make fifth wheel that our colleague lost the trailer from after some 120 miles empty motorway running.
It happens see
nick2008:
Juddian:
Funnily enough it was a BigD that locked home with the pin sitting on the jaws (to be fair the trailer had been dropped empty on the ■■■■ for loading, heavy too so had to force the fifth wheel under), and the same make fifth wheel that our colleague lost the trailer from after some 120 miles empty motorway running.It happens see
You misunderstand me, these weren’t fifth wheel failures, they were two instances of miscoupling with the pin sitting on instead of locked inside perfectly serviceable jaws, my colleague didn’t realise his mistake and lost the trailer, i was fortunate enough to have his catastrophe in the back of what loosely passes for my mind, though the sound of connection wasn’t typical…thankfully after i drew the vehicle onto some level ground and had a look see, the problem was obvious.
I can understand…
Missing the pin before we had air suspension. A badly dropped trailer in the docks, un-even ground and ■■■■■■■ it down with rain. The only way you could get it level if it had been dropped high was to get your leg winding handle out of your cab, put the bolt in and wind the bugger back down on the legs. So yeh, mistakes were made because all drivers wanted to do was get the ■■■■ thing on and get going.
Without looking at the king pin on the trailer in question, it’s impossible to determine wether its equipment failure or driver error. My money’s on driver error.
I’m still watching drivers dropping and collecting trailers in our yard with no real idea what they are actually doing. Hence we sometimes have empty trailers jacked right up and loaded ones dropped almost on the ground. It’s the sort of thing that a practical DCPC could teach because a classroom of bored drivers staring out of the window or checking their Fakebook status teaches nothing. Couple that with the ‘sign this drive’ explaining on an A4 piece of paper how to drop and pick up trailers which also teaches nothing and hasn’t prevented trailers being dropped flat on their nose.
As mentioned above there are adjuster and lock knuts at the side of the 5th.wheel to enable the slack of wear over time to be rectified.I suppose if this was ignored the excess movement of the pin within the jaws could cause damage but the driver would have to be that bit special not to notice it while driving.
I have experienced a sheared pin once while working in Saudi.While discharging a trailer from a ship one of our philipino tug drivers was a bit vigorous hooking up to a trailer,shearing the pin and burying the front of the trailer in the back of his cab.He was a bit surprised but carried on.All our philipinos were good guys whatever their trades.
Rowley010:
peirre:
As part of my routine I duck down and shine a torch to see if the 5th wheel had locked in placeI’m glad I’m not the only one who does this. Never really see anyone do it though
One old guy said this to me when i started and he said it’s the best bit of advice anyone would ever give me. I still do it.
nick2008:
Trickydick:
nick2008:
It don’t have to be a pin failure.
We’ve had instances where the jaws have failed, movement on the road nuts and bolts working loose off the gas pressure is taken off the pin / jaws, they come apart foot back on the accelerator and bang trailer gone.Gets me everyone thinks driver error
Nick which nuts and bolts come loose to allow the jaws to fail? also what gas pressure?
Ok accelerator pedal and do you know it’s not held together by magic dust it has nuts and bolts in it
You do realise the left highlighted bolt is in fact the adjuster bolt and nothing else just an adjuster?
You also didnt answer my question ref what gas pressure?
I can have a look on wikipedia for you if its any help?
nick2008:
Juddian:
Funnily enough it was a BigD that locked home with the pin sitting on the jaws (to be fair the trailer had been dropped empty on the ■■■■ for loading, heavy too so had to force the fifth wheel under), and the same make fifth wheel that our colleague lost the trailer from after some 120 miles empty motorway running.It happens see
When was the last time you saw a York Big D?
Gidders:
As mentioned above there are adjuster and lock knuts at the side of the 5th.wheel to enable the slack of wear over time to be rectified.I suppose if this was ignored the excess movement of the pin within the jaws could cause damage but the driver would have to be that bit special not to notice it while driving.
I have experienced a sheared pin once while working in Saudi.While discharging a trailer from a ship one of our philipino tug drivers was a bit vigorous hooking up to a trailer,shearing the pin and burying the front of the trailer in the back of his cab.He was a bit surprised but carried on.All our philipinos were good guys whatever their trades.
I have seen trailer king pins cracked around the rubbing plate, but this was 30 yrs ago when everyone ran real old bits of carp and they ran them until they literally died, nowadays you dont really see proper old trailers.
We used to cut out the old plates and fit new rubbing plates as the old ones were so curved up in the middle as they were totally shagged/rotten and all the chassis x members had rotted out, again this wasnt unusual.
Carryfast:
switchlogic:
Christ, American trucks really are made of cardboard aren’t they?!
The result of trying to provide for a viable payload within a silly gross weight regime.A bit like plastic cabbed Brits running at 32t gross.
Yeah American weight limits have always baffled me…though going by the state of many of their roads they can’t deal with the weight they do carry.
Trickydick:
nick2008:
Trickydick:
nick2008:
It don’t have to be a pin failure.
We’ve had instances where the jaws have failed, movement on the road nuts and bolts working loose off the gas pressure is taken off the pin / jaws, they come apart foot back on the accelerator and bang trailer gone.Gets me everyone thinks driver error
Nick which nuts and bolts come loose to allow the jaws to fail? also what gas pressure?
Ok accelerator pedal and do you know it’s not held together by magic dust it has nuts and bolts in it
You do realise the left highlighted bolt is in fact the adjuster bolt and nothing else just an adjuster?
You also didnt answer my question ref what gas pressure?
I can have a look on wikipedia for you if its any help?
It’s pretty easy to understand if you take a few seconds to read the words and put in the rather obviously missing punctuation:
We’ve had instances where the jaws have failed (as a result of) movement on the road and nuts & bolts working loose. (When you take your foot) off the gas, pressure is taken off the pin/jaws and they come apart. Foot back on the accelerator and - trailer gone…
sammym:
Question for you all.How can you get so far if you are not coupled up properly? If I pull the pin I’ve never had a the trailer come with me when I uncouple… It clicks out, I dropped air and drive away.
I think someone said something about half catching the pin etc… If I raise the trailer up with my air suspention and then connect to the pin can this still happen? I’m asking as I don’t wanna be in this sort of position myself.
Cheers
Simple. If the dog clip is in, the pin is properly seated. If you can’t get it in, the pin hasn’t caught correctly.
In this case, if the dog clip was in it was pin failure, if it wasn’t then expect a driver to be talking to a man in a wig before a long stay in a bad holel.
nsmith1180:
sammym:
Question for you all.How can you get so far if you are not coupled up properly? If I pull the pin I’ve never had a the trailer come with me when I uncouple… It clicks out, I dropped air and drive away.
I think someone said something about half catching the pin etc… If I raise the trailer up with my air suspention and then connect to the pin can this still happen? I’m asking as I don’t wanna be in this sort of position myself.
Cheers
Simple. If the dog clip is in, the pin is properly seated. If you can’t get it in, the pin hasn’t caught correctly.
In this case, if the dog clip was in it was pin failure, if it wasn’t then expect a driver to be talking to a man in a wig before a long stay in a bad holel.
There’s a difference between a miscoupled trailer in which the pin has fouled the closed jaws v a released fifth wheel.The trailer certainly can go a considerable distance without falling off in the case of the former.
While going under low and then lifting the unit,hopefully before the pin has entered the jaws,introduces too many variables and room for error in that regard.The trailer needs to be sitting at a lower height than the fifth wheel from the start so that it’s ‘lifted’ and resting with all of its weight on the fifth wheel from the first point of contact.
Carryfast:
While going under low and then lifting the unit,hopefully before the pin has entered the jaws,introduces too many variables and room for error in that regard.The trailer needs to be sitting at a lower height than the fifth wheel from the start so that it’s ‘lifted’ and resting with all of its weight on the fifth wheel from the first point of contact.
Forget your archaic “pre air” coupling technique and show some sympathy towards the equipment, which you may well find out for yourself if you ever end up gainfully employed in the 21st century!
1, Approach low (air down)
2, STOP when fifth wheel has gone under trailer
3, RAISE suspension until trailer visibly lifts a few inches
4, Reverse until cli-clunk of fifth wheel jaws locks around pin
5, When trailer is all attached, checked and ready to drive away reset air to drive position.
If/when you become competent enough you’ll do steps 1 through 4 in one single fluid precise manoeuvre knowing exactly how far under the trailer you’ve gone via visual and audible cues, but for you cf i suggest baby steps as you may struggle with so many button presses on the new fangled remote whatsibob.
This ^^^^^ every time. It really is that simple with absolutely no need to unnecessarily complicate things.
Reef:
Carryfast:
While going under low and then lifting the unit,hopefully before the pin has entered the jaws,introduces too many variables and room for error in that regard.The trailer needs to be sitting at a lower height than the fifth wheel from the start so that it’s ‘lifted’ and resting with all of its weight on the fifth wheel from the first point of contact.Forget your archaic “pre air” coupling technique and show some sympathy towards the equipment, which you may well find out for yourself if you ever end up gainfully employed in the 21st century!
1, Approach low (air down)
2, STOP when fifth wheel has gone under trailer
3, RAISE suspension until trailer visibly lifts a few inches
4, Reverse until cli-clunk of fifth wheel jaws locks around pin
5, When trailer is all attached, checked and ready to drive away reset air to drive position.If/when you become competent enough you’ll do steps 1 through 4 in one single fluid precise manoeuvre knowing exactly how far under the trailer you’ve gone via visual and audible cues, but for you cf i suggest baby steps as you may struggle with so many button presses on the new fangled remote whatsibob.
As I said it can all go horribly wrong if/when someone inevitably gets 2 and 3 even slightly wrong.In which case 3-5 will still happen effectively as described with the added bonus of 6 lose trailer at any random point.Which is probably why training schools obviously still use my ‘archaic’ method on the basis if it ain’t broke don’t fix it ( also probably don’t want the inconvenience of someone saying this is how I was shown in the investigations into the resulting carnage ).Bearing in mind that I was quite familiar with air and a remote whatsit on later DAF’s.Strange how I very rarely,if ever,needed to use it to couple or uncouple anything just as shown in the numerous training vids out there.
CF I just luuurve how you who hasn’t dropped anything larger than a ■■■■ let alone a trailer this century insists that we are doing it all wrong! I usually change trailers once or as many as four times a day using the method that Reef posted above, yet I’m wrong! You are constant if nothing else.
If he does start driving trucks again he’ll be horrified at how rare run up ramps are becoming! A lot of the companies I’ve worked for take them off to avoid Carryfasts brutal coupling method. You’d think a former engineer would have more mechanical sympathy 