Been working agy mainly an ongoing contract for highstreet shop deliveries in 18 ton class 2, with the odd quick help we need a driver urgent class 1 thrown at me for good measure.
I have done some container work FH12 where when there is weight on the lift axle dropped automatically great less things for an inexperienced rookie to think about.
Anyway yesterday I got a call from the agy to do trunk trailer swap in Sedbury layby Scotch Corner with a fridge unit. I was told about a small airleak but no problem when running only losing air at long standstill.
Got to the drop and had a wait switched of engine Scanny R420, not long after warning RED air very low, called contact who said no probs will drive fine when the system tops.
Did the trailer swap and “assumed”, daft I know that because I had pallets loaded on the way down that I would be empty on the way up. Lift axle is up after swap so again based on my FH12 experiences assume that the trailer is empty or the lift axle would have grounded itself.
Got moving and knew right away not only was I loaded but heavier than on the way down, dash board shows lift axle to be up. I never switched it down for two reasons both loaded trailers where no where near the weights I had experienced with the container work and I thought maybe I was just not carrying enough for the lift axle to drop. Or the air problem maybe had something to do with it not dropping.
The handling didn’t seem to be affected but I realise I should not rely on the truck to do the thinking for me, so could someone kindly fill in the blanks about lift axle use.
like slow says it will drop if its too heavy not sure about weight obviously depends what your carrying i have had 52 pallets on an tag stays up yet tonight i had 17 on n it dropped i prefer to have it up myself but a word of warning in a scanny when the tag is up the trailer height raises too by a few inches u may or may not know this but something to bear in mind when coming to a bridge
The Scania mid-lift axle isn’t far off the ground, compared to say, a DAF or Volvo and will normally
put itself down automatically,if the trailer is heavy enough, accompanied by a fairly loud hissing noise.
I am not being sarcastic, a Scania will put the tyres on the ground and not put the axle down.
This leaves it with no weight on it and the tyres will skid every time you brake.
Running with the axle up, when the trailer is lightly loaded, usually means that the mid lift tyres will catch on the road over bumps, which does them no good at all, especially if you are braking.
Best to set the switch to the down position, unless the trailer is empty, in my opinion.
You also get an extra set of brakes, not a Scania’s strong point, so the more the better.
In my experience, getting the axle to lift is more tricky, as the Scania mid lift axle will only work correctly when the air pressure is fully up and the axle weights are correct.
If you set it to lift and they are not correct, it will then not lift at all until you have reset it to down and the weights and air pressure are correct.
not sure about weight obviously depends what your carrying i have had 52 pallets on an tag stays up yet tonight i had 17 on n it dropped
This was possibly due to the weight distribution in the trailer.
Any part of the load that is behind the trailer wheels takes weight off the pin.
It is therefore quite likely that only 17 pallets, if all at the front, could put more weight onto the tractor unit than 52, with some of them behind the trailer wheels.
For your benefit in this situation, the Volvo FH12 lifts tend to be a bit of a bugger (Asuming your in a 52 reg or newer).
The button is on the dash and should be left in the middle position, this way the truck does the thinking. If your reversing or in the yard switch it to the up position to lift it. This makes reversing easier and won’t ■■■■ the boss off.
In a Scanny, again asuming it’s a new one, It’s usually to the left of the steering wheel, again these tend to behave more often and just as simple.
The handling shouldn’t be affected that much either way, but as soon as you hook up and set off the truck will decide for itself.
I drive a rigid with rear steer so abit different, but i leave it down if there is anything more than about 3t on the bed. I know people who always leave them down though just for the extra braking.
Dunno if all modern Scanny’s have it but on mine there is an info button on the bottom of the steering wheel, this gives you several trip computer type functions on the display but also one which gives weights on the axles that have air suspension.
It’s handy to keep a check on my axle limits as I load everything myself. What is irritating though is that my axles are rated
8500kg
8500kg
11500kg
8500kg
with the tag axle (4) lifted the weight on the drive axle (3) is 7500kg, if I loaded 3t on to the drive axle it will drop the tag and not me lift it as it says it will overload the axle
Lift axles are governed by a EU directive so that the lifting of an axle cannot overload any other axles, its all programed into the ECU which looks at the axle weights and decides if lifting can be allowed or not, also the lift axle should come down automatically when a pre-determined weight is sensed.
I’m not sure about other makes but on a Scania there is what they call a load transfer function which removes all the air from the lift axle air bags, and therefore the weight. This transfers the weight onto the other axles and more importantly the drive axle to give better traction on slippy surfaces, now the button for this is next to the button for lifting on an R series and on a 4 series is the same button for lifting, all this may explain why some times the axle doesn’t lift and skids under braking, but the standard programming for this is only 90 seconds or if vehicle speed is over 25kph normal weight distribution should be restored.
As for the lift axle not clearing the ground very much this is usually the lifting cables streached, or the cable eyelets break up.
Thanks for all the info, quite technical . I think my confusion comes from the fact that I thought that the axle only lifted when empty.
The weights when I was doing containers were between 18 and 26 ton of Scotlands finest, and the axle always grounded, with an empty container it was always lifted.
I suppose the trunked palleted trailers were somewhere in the middle, I was not told anything about the weight just that it was palleted foodstuffs.
So if I’ve got this right the truck decides and if it’s got a manual switch don’t touch because I’m still none the wiser.
Redrorry:
Thanks for all the info, quite technical . I think my confusion comes from the fact that I thought that the axle only lifted when empty.
The weights when I was doing containers were between 18 and 26 ton of Scotlands finest, and the axle always grounded, with an empty container it was always lifted.
I suppose the trunked palleted trailers were somewhere in the middle, I was not told anything about the weight just that it was palleted foodstuffs.
So if I’ve got this right the truck decides and if it’s got a manual switch don’t touch because I’m still none the wiser.
Is there not a more experienced guy in the yard that can give you abit of advice, as i assume they’ll being doing the same work as you, or have done it? If it was me and i really was that unsure id leave it down, not ideal but it covers you.
Saaamon:
Is there not a more experienced guy in the yard that can give you abit of advice, as i assume they’ll being doing the same work as you, or have done it? If it was me and i really was that unsure id leave it down, not ideal but it covers you.
The company I do regular work for is class 2, the class 1 jobs the keys are usually thrown your way because the usual guy did not turn up. “It’s over there drive”.
My limited understanding of lift axles are they help take/distribute axle weigh and give more traction. Also now that I’ve read this an extra set of brakes (always handy things to have).
The general concensus I’m getting is if I’m laden and unsure of the weight being hauled then switch the axle to the down position if It doesn’t drop automatically.
Saaamon:
Is there not a more experienced guy in the yard that can give you abit of advice, as i assume they’ll being doing the same work as you, or have done it? If it was me and i really was that unsure id leave it down, not ideal but it covers you.
The company I do regular work for is class 2, the class 1 jobs the keys are usually thrown your way because the usual guy did not turn up. “It’s over there drive”.
My limited understanding of lift axles are they help take/distribute axle weigh and give more traction. Also now that I’ve read this an extra set of brakes (always handy things to have).
The general concensus I’m getting is if I’m laden and unsure of the weight being hauled then switch the axle to the down position if It doesn’t drop automatically.
Thank for, didn’t really think about it untill I saw this thread. Is there any info on here about it, would save me google for it and finding loads of crap lol
Andydan:
Thank for, didn’t really think about it untill I saw this thread. Is there any info on here about it, would save me google for it and finding loads of crap lol
What is it that your un-sure about? I’m not really the best person to answer questions but i’m someone else who is will be watching.
To be honest I don’t know much about it at all. I was thinking is was more of an automatic thing. Sort of get loaded, press a button and the unit sorts it out.
Andydan:
To be honest I don’t know much about it at all. I was thinking is was more of an automatic thing. Sort of get loaded, press a button and the unit sorts it out.
Yep that does happen self levels on the MAN & Volvo I have drove that had them the Renault didnt have 1 so didnt have to worry about it
