Winseer:
If your trailer starts to swing around the side of you, then you floor the accelerator (in the dry and straight) and flick the trailer brake/handbrake to effectively “jerk the combination straight again”.
If you’re going around a corner, it won’t work. If it’s icy it won’t work. If it’s wet, it might still not work.
There’s a reason of course that we have a yellow airline as well as a red one. You can drive it around on “only” the red, but I wouldn’t advise it. Shunters do it all the time, but even they run into the occasional bother come the rain and snow…
Are you for real?
Please enlighten me as to why we have a yellow airline,as well as a red one? you sound like a professional driver who i could learn a few things from. Flick the handbrake lol Wtf,i wouldn’t let you drive my dyson round the living room.
It’s scary that some people don’t know basic things, Then naive people like Shoshaye try to take the mick out of someones obviously good advice, It’s the sort of thing that most drivers would already know.
Shoesaye, does your dyson not have a secondary braking system? this thread has gone on for many months and I am still learning from it. Like Phil I am learning that there are too many people driving trucks who do not understand the basic controls.
The handbrake valve has two purposes, the hand valve has three positions, off, on, and locked on. The next time you are on a straight quiet road, try it out it may just save your life or save you blocking the road for 12 hours. Before this type of valve we had the “Dead Mans Handle” like those fitted to Volvo F88 and Scania 112. We also used the Clayton Dewandre type valves which also had two positions and you had to push the lever forward to charge the system before you could release the parking brake.
Long before Anti Blockier Systems and Girling Skidcheck, we used cadence braking techniques, before we had air gauges and buzzers we had semaphore flags that popped up out of the dashboard or demister slots
I remember those flags. The buzzer went and this thing came slowly up out of it’s slot… always reminded me of a ■■■■.
What carryfast says, used to happen here in Oz. I came out here in '74 and there were a few trucks with front brake pipes blocked off. The bogie drives (double drive) did help with stopping, but like other people say, once she goes, she goes and there ain’t a lot you can do unless you’re quick and have plenty of room.
I haven’t actually jacknifed up hill, but I was empty going through Narrow St at Limehouse back in the 60’s when it was all cobblestones. It’s peeing with rain and I’m doing about 20mph when she just decided to park up. I just slid straight into the kerb, dead straight, looking as though I wanted to stop. Didn’t half feel a berk.
Winseer:
If your trailer starts to swing around the side of you, then you floor the accelerator (in the dry and straight) and flick the trailer brake/handbrake to effectively “jerk the combination straight again”.
If you’re going around a corner, it won’t work. If it’s icy it won’t work. If it’s wet, it might still not work.
There’s a reason of course that we have a yellow airline as well as a red one. You can drive it around on “only” the red, but I wouldn’t advise it. Shunters do it all the time, but even they run into the occasional bother come the rain and snow…
Are you for real?
Please enlighten me as to why we have a yellow airline,as well as a red one? you sound like a professional driver who i could learn a few things from. Flick the handbrake lol Wtf,i wouldn’t let you drive my dyson round the living room.
It’s scary that some people don’t know basic things, Then naive people like Shoshaye try to take the mick out of someones obviously good advice, It’s the sort of thing that most drivers would already know.
Shoesaye, does your dyson not have a secondary braking system? this thread has gone on for many months and I am still learning from it. Like Phil I am learning that there are too many people driving trucks who do not understand the basic controls.
The handbrake valve has two purposes, the hand valve has three positions, off, on, and locked on. The next time you are on a straight quiet road, try it out it may just save your life or save you blocking the road for 12 hours. Before this type of valve we had the “Dead Mans Handle” like those fitted to Volvo F88 and Scania 112. We also used the Clayton Dewandre type valves which also had two positions and you had to push the lever forward to charge the system before you could release the parking brake.
Long before Anti Blockier Systems and Girling Skidcheck, we used cadence braking techniques, before we had air gauges and buzzers we had semaphore flags that popped up out of the dashboard or demister slots
And your point is what exactly? I fully understand how my brakes work,I started working in my grandads garage when I was 12. and won’t be pulling the hand brake any time soon while I’m moving. If someone finds your advice useful then I wish them the best of luck.
Shoshaye:
I started working in my grandads garage when I was 12. and won’t be pulling the hand brake any time soon while I’m moving.
Why not?
All drivers should practice use of the secondary braking system, its there for a reason - as a life saver if the service brake fails. Many drivers are blissfully unaware of its existence.
IMHO true a true jack knife is when the trailer pushes the unit round and you end up with a nearside full of trailer.
I believe the reason we are seeing more of these lately is owing to bad planning/ loading. How many of us have had issues with traction on wet roads especially going uphill. Surely if there’s less weight on the pin and in turn the drive axle the drive axle is more likely to lock and in turn the trailer will just keep going and force you round.
Feel free to tell me how wrong I am as a lot of you have more experience driving than I do breathing.
There’s 2 causes of a jack-knife, wheel slip and trailer swing.
Wheel slip is where the drive wheels start moving sideways (Ice, aquaplaning, etc)
Trailer swing is where the trailer wants to overtake the unit (duff brakes etc)
Modern technology, alert driving manner, adequate driver / maintenance checks and not dozing off at the wheel should preclude most of the reasons for trailer swing, being aware of road conditions, weather etc should preclude most of the reasons for wheel slip.
Quite why there are so many jack knife incidents these days usually comes down to the nut holding the steering wheel.
hi, years ago a mate of mine asked me if I would drive his motor on a night trunk for a week. I was driving a taxi for a bit, so said it would be ok. it was a scania with a curtain sider. from the offset I thought it was a bit twitchy, but one night in the rain it started to go under normal driving near fort Dunlop. it was ok, just backed off and it was ok. it turned out to be an iffy load sensing valve on the tractor. regards ray.
… Although I only have 25yrs of HGV 1 driving, I understand a jack knife to be the result of the units drive wheels losing grip & being pushed sideways by the inertia of the trailer??- with this in mind I never use the engine/exhaust/jake brake on a bend or slippery surface (also bear in mind that a lot of eng/ext/jake brakes are auto linked (unless switched off) to the footbrake)
This is quite a good vid explaining load/vehicle dynamics
I think a lot is to do with being on cruise and the exhaust brake slows the unit, the trailer having no braking tries to push the unit forward being heavier. Or maybe not Edit, post above beat me to it
ADR 1:
… Although I only have 25yrs of HGV 1 driving, I understand a jack knife to be the result of the units drive wheels losing grip & being pushed sideways by the inertia of the trailer??- with this in mind I never use the engine/exhaust/jake brake on a bend or slippery surface (also bear in mind that a lot of eng/ext/jake brakes are auto linked (unless switched off) to the footbrake)
This is quite a good vid explaining load/vehicle dynamics
i agree 100% you’ve got to remember that when you apply the exhaust brake it only slows the unit down and not the trailer the trailer is still trying to go at the same speed and in turn tries to push the unit out of the way ?
The nearest i have come to a jacknife situation was one one occasion when i was turning right, i pulled out onto the main road and has i was steering it round the trl started pushing the unit round on me, the roads where damp as it had rained within hours , The trl i think was on it’s weight limit, or had been loaded incorectly (too much weight on the pin)
tommy t:
The nearest i have come to a jacknife situation was one one occasion when i was turning right, i pulled out onto the main road and has i was steering it round the trl started pushing the unit round on me, the roads where damp as it had rained within hours , The trl i think was on it’s weight limit, or had been loaded incorectly (too much weight on the pin)
