FarnboroughBoy11:
how can it jack knife when the braking was done all from the trailer wheels which is trying to pull the unit back, a jack knife is where the trailer pushes the unit round.
When the red airline goes the brakes come on in the unit and trailer. I’ll guess the units air tank empties out quicker than the trailers ? Either way the unit will lock up quicker than a loaded trailer which would have more weight to push it.
Trailer only Mike. The multi curcuit protection valve should stop this from happening so in other words, the air tank on the unit which feeds the red air line would deplete but all other tanks on the unit would remain full.
Happened to me a couple of times pulling German trailers with dodgy palm couplings. Luckily never heavy but with a 460 on cruise on the limiter it doesn’t half lay some rubber down and send some blue smoke up in the air. And yes it panics anyone who’s a bit clise behind you. Another reason never to tailgate…
Nothing to do with air tanks emptying first.As soon as a loss of pressure is sensed at the emergency relay valve on the trailer the air is dumped out the trailer spring brakes,the tractor will still have full air in its chambers and the brakes will be off.
There is no way you can brake faster than a relay valve to cause a jack knife.
FarnboroughBoy11:
The amount of trucks I get in to move or shunt or drive or whatever where the previous driver has hardly turned the collar round is a joke. Lazy knobs.
But anyway I think he was talking out of it arse, how can it jack knife when the braking was done all from the trailer wheels which is trying to pull the unit back, a jack knife is where the trailer pushes the unit round.
You’re assuming the driver didn’t jam on the brakes when it happened, which on a wet road would cause such a pickle. We know you’re the worlds greatest driver and would have brought it to a controlled stop in a second with no damage whatsoever but some of us might panic
I was assuming that yes. I do apologise. I am guilty of expecting far too much from other drivers. Of course he panicked and lost it and caused 15 grands worth of damage, he couldn’t have just eased it over to a controlled stop like a few of the posters above did, that would be too difficult wouldn’t it.
FarnboroughBoy11:
how can it jack knife when the braking was done all from the trailer wheels which is trying to pull the unit back, a jack knife is where the trailer pushes the unit round.
When the red airline goes the brakes come on in the unit and trailer. I’ll guess the units air tank empties out quicker than the trailers ? Either way the unit will lock up quicker than a loaded trailer which would have more weight to push it.
I was basing my answer on if the collar popped off in which case the valve would close.
But yes, I had a dodgy valve in my red airline a couple of weeks back, when ever I dropped a trailer and was solo I had to kink it to stop the air ■■■■■■■ out… It’s surprisingly loud when the air is coming straight out, my ears were ringing.
FarnboroughBoy11:
The amount of trucks I get in to move or shunt or drive or whatever where the previous driver has hardly turned the collar round is a joke. Lazy knobs.
But anyway I think he was talking out of it arse, how can it jack knife when the braking was done all from the trailer wheels which is trying to pull the unit back, a jack knife is where the trailer pushes the unit round.
You’re assuming the driver didn’t jam on the brakes when it happened, which on a wet road would cause such a pickle. We know you’re the worlds greatest driver and would have brought it to a controlled stop in a second with no damage whatsoever but some of us might panic
I was assuming that yes. I do apologise. I am guilty of expecting far too much from other drivers. Of course he panicked and lost it and caused 15 grands worth of damage, he couldn’t have just eased it over to a controlled stop like a few of the posters above did, that would be too difficult wouldn’t it.
I don’t really care what could or could not have happened, I was just pointing out how a jackknife could have happened and therefore that the poster wasn’t necessarily ‘talking out of it arse’, whereas it could be argued you were. As you were.
Trailer only Mike. The multi curcuit protection valve should stop this from happening so in other words, the air tank on the unit which feeds the red air line would deplete but all other tanks on the unit would remain full.
if you forget to disconnect the red line whilst shunting etc, drive off and split the red line…the unit comes to a stop.
Regardless of other air tanks being full.
Certainly when my red line parted on the M42 a while ago everything locked up in very short order.
del949:
if you forget to disconnect the red line whilst shunting etc, drive off and split the red line…the unit comes to a stop.
Regardless of other air tanks being full.
Certainly when my red line parted on the M42 a while ago everything locked up in very short order.
I might be wrong but I thought that was not meant to happen.
Yep 1987, red line coupling parted @ 60mph empty on motorway, the black lines were there for days, tandem axled trailer, all 8 tyres flatted.
They don’t jack knife, but they can pull to one side and end up with the trailer in lane one and the tractor on the hard shoulder when it stops finally, no danger of anyone hitting it mind, you couldn’t see a thing for smoke and all traffic stopped.
The mechanics put it down to poor quality (cheap pattern crap, probably bloody Chinese) couplings…think they were vindicated somewhat as they had been complainig about shoddy parts.
FarnboroughBoy11:
The amount of trucks I get in to move or shunt or drive or whatever where the previous driver has hardly turned the collar round is a joke. Lazy knobs.
But anyway I think he was talking out of it arse, how can it jack knife when the braking was done all from the trailer wheels which is trying to pull the unit back, a jack knife is where the trailer pushes the unit round.
You’re assuming the driver didn’t jam on the brakes when it happened, which on a wet road would cause such a pickle. We know you’re the worlds greatest driver and would have brought it to a controlled stop in a second with no damage whatsoever but some of us might panic
I was assuming that yes. I do apologise. I am guilty of expecting far too much from other drivers. Of course he panicked and lost it and caused 15 grands worth of damage, he couldn’t have just eased it over to a controlled stop like a few of the posters above did, that would be too difficult wouldn’t it.
I don’t really care what could or could not have happened, I was just pointing out how a jackknife could have happened and therefore that the poster wasn’t necessarily ‘talking out of it arse’, whereas it could be argued you were. As you were.
I never said the poster was talking out of his arse, I said the bloke that told him probably was. But I suppose “my lorry jackknifed” sounds better than “I crashed my lorry”. As you were.
Lusk:
I’m not sure although suspect possible damage prior which weakened it.
should have been spotted on pre use checks though
Are you saying you stretch the suzies out and examine them fully before use?
I’ll refrain from callin you a ■■■■. A quick check for kinks and nicks would do as would checking for leaks. Also if jacknifing a trailer its best to not over stretch much like having too many Gareth Hunts will cause friction and damage equipment my old son
TOECUTTER:
Had that happen flat spotted 6 super singles BADLY…
Thats all I would have expected to happen but the other day, there was a haulier down in the west country who had a red air line fail whilst he was going 56 mph on the motorway and the end result was a £20k repair bill because the vehicle jacknifed.
I was under the impression that if this happened and the trailer had EBS fitted to it, then the system would not immediately go into emergency mode and apply the brakes until the vehicle got to beneath a certain speed.
The EBS will act on the brakes if the signal line comes off by sensing pedal pressure signal from electric foot valve to trailer ecu but the red line causes instant lock out.
About 9 or 10 year ago, a few mile south of Markham Moor on the A1, a tipper overtook a Reed Boardall (IIRC) & after he had pulled back in, his red line parted.
Reed Boardall ploughed into the back of him & his reefer shot the pin & crushed his cab against the tipper.
The driver sadly died immediately.
Lusk:
I’m not sure although suspect possible damage prior which weakened it.
should have been spotted on pre use checks though
Are you saying you stretch the suzies out and examine them fully before use?
I’ll refrain from callin you a ■■■■. A quick check for kinks and nicks would do as would checking for leaks. Also if jacknifing a trailer its best to not over stretch much like having too many Gareth Hunts will cause friction and damage equipment my old son
There could still be previous weakening that you can’t see. It like saying checking a tyre will guarantee you won’t get a blowout whilst you are on the road. But if you say so I bow to your superior knowledge…
Lusk:
I’m not sure although suspect possible damage prior which weakened it.
should have been spotted on pre use checks though
Are you saying you stretch the suzies out and examine them fully before use?
I’ll refrain from callin you a ■■■■. A quick check for kinks and nicks would do as would checking for leaks. Also if jacknifing a trailer its best to not over stretch much like having too many Gareth Hunts will cause friction and damage equipment my old son
There could still be previous weakening that you can’t see. It like saying checking a tyre will guarantee you won’t get a blowout whilst you are on the road. But if you say so I bow to your superior knowledge…
There’s always a risk. What I’m saying is as long as you check your equipment you reduce the likelihood of failure. Not like the previous post … by stretching out the air line… that’s just being dumb.
