Well after 8 months of driving Class 1 without any mishaps I’ve messed up this week and I’m a bit peeved about it especially as I can’t seem to figure out the solution myself.
Been driving a Scania,(not sure which model but no matter). It has the switches to lift the axle up and down by the right knee. Looks like one switch to activate and the other to either lift or drop. I’m more used to the hand held box on the end of the wire!!!
Anyway the problem I’ve had this week is when dropping the trailer. After doing the necessaries and pulling away from under the trailer the trailer is hitting the rear mud guards. I’m not sure whether its the unit raising or the trailer dropping.
I’ve never had this problem with any other units I’ve driven. Any advice greatly received.
I would make sure the legs on the trailer are wound all the way down - if they’re not (it’s on a slope or something), then their’s going to be a slight drop when you put the trailer down and that will be enough to catch the flaps. Check that you’ve actually got the suspension down when you er pull out, so to speak. Like you say, it’s the button on your right knee with the one on the left to activate it. Also check that the suspension’s workink. Might sound like a daft statment, I know, but you’d be suprised how many don’t though (and yes, I do know how to work it before anyone starts).
Hope this makes sense and is of some help.
Cheers
Ian.
Sometimes you actually have to have moved if it’s an older unit to get the air up to shift the suspension/return it to it’s level.
Assuming the suspension is working okay, get your trailer in the position you want to drop it, grab your air control (suspension control pad thingy on the wire down the side of the seat) and raise the suspension a few inches then go and wind the leg downs all the way to the ground, do all the other stuff involved to drop the trailer off then put it in first gear, pull forwards about 1ft to disengage the pin, grab your air control again and press the button to drop all the air out - give it 15 - 20 seconds for it to work properly and then just pull out, job done.
Sounds to me like you’re not winding the legs down fully OR you’re dropping the air out before winding the legs down which would also produce the problem you’re having.
It is quite normal for the mudguards to hit when you are dropping or picking up a trailer, Quite often happen when the kingpin on the trailer is set a fair way back so there is more of the trailer to reverse under. I normally find Premiums are quite bad for it. And alot of 6 wheel midlifts are also bad for it.
smcaul:
It is quite normal for the mudguards to hit when you are dropping or picking up a trailer, Quite often happen when the kingpin on the trailer is set a fair way back so there is more of the trailer to reverse under. I normally find Premiums are quite bad for it. And alot of 6 wheel midlifts are also bad for it.
I would suggest you need to alter your practices for coupling and uncoupling then as in all the time I’ve been driving I could count on one hand the amount of times the trailer has contacted the mud guards and believe me, that it is very very few. That is what the ramps are there for.
smcaul:
It is quite normal for the mudguards to hit when you are dropping or picking up a trailer, Quite often happen when the kingpin on the trailer is set a fair way back so there is more of the trailer to reverse under. I normally find Premiums are quite bad for it. And alot of 6 wheel midlifts are also bad for it.
I would suggest you need to alter your practices for coupling and uncoupling then as in all the time I’ve been driving I could count on one hand the amount of times the trailer has contacted the mud guards and believe me, that it is very very few. That is what the ramps are there for.
Nothing wrong with my proceadures, Must just be different to yours, Having said that, I do like to make sure that I “Pick Up” the trailer rather then just backing under it as I have had the king pins drop over the front of the 5th wheel and my method reduces that risk.
All I was saying is that it is not abnormal for the mudguards to hit the trailer, I was not commenting on the right or wrong way of doing something.
One of the things I tried was to raise the suspension before dropping the legs. Then I flicked the switch to lower the suspension thinking that’s going to give me more room. But it doesn’t seem to go down very much . Im wondering now if I’m not giving it enough time.
Doesn’t seem to lower as fast as the other units I’ve driven. I’ll try giving it more time on Tuesday 'cos I’ve got the same one again.
One of the things I tried was to raise the suspension before dropping the legs. Then I flicked the switch to lower the suspension thinking that’s going to give me more room. But it doesn’t seem to go down very much . Im wondering now if I’m not giving it enough time.
Doesn’t seem to lower as fast as the other units I’ve driven. I’ll try giving it more time on Tuesday 'cos I’ve got the same one again.
Flicked a switch. What switch is this then, where is it ? Bet you’re on about the lift axle switch - does it have pictures of circles on it
One of the things I tried was to raise the suspension before dropping the legs. Then I flicked the switch to lower the suspension thinking that’s going to give me more room. But it doesn’t seem to go down very much . Im wondering now if I’m not giving it enough time.
Doesn’t seem to lower as fast as the other units I’ve driven. I’ll try giving it more time on Tuesday 'cos I’ve got the same one again.
Those Scania’s will take about 4 to 5 times longer to lower then a DAF for example. They are a real pain if you are doing Wag and Drag box swaps purly because of the time it takes to dump the air out. They also dont like not having a load to help them dump the air out.
every company or boss has a pet hate, ours is anyone scraping the mudguards when dropping trailers or running round the yard with the tyres rubbing the mudguards.
There is no need to do either, just lift the suspension up before dropping the legs and drop the suspension on the unit before you reverse up to the pin.
If you cant get the height correct by using the wander lead, drop or raise the trailer suspension, it does the same thing.
We dont have run up ramps, I cant remember the last time I had a truck with them. Maybe DHL, but as we never dropped the trailer, it wasnt a problem.
I think this post was originally about a Scania, but air bags are the same whatever method of operation, wander lead or rocker switches is the same
there is a difference the ones with the wander lead have ecas electronic air suspension the ones with the rocker switches are not ecas and take around 3 times as long to drop one tipp is to leave the park brake on as nyou dropping the air then take the brake off and the back ot the unit will drop
Rob K:
Assuming the suspension is working okay, get your trailer in the position you want to drop it, grab your air control (suspension control pad thingy on the wire down the side of the seat) and raise the suspension a few inches then go and wind the leg downs all the way to the ground, do all the other stuff involved to drop the trailer off then put it in first gear, pull forwards about 1ft to disengage the pin, grab your air control again and press the button to drop all the air out - give it 15 - 20 seconds for it to work properly and then just pull out, job done.
Sounds to me like you’re not winding the legs down fully OR you’re dropping the air out before winding the legs down which would also produce the problem you’re having.
Yeah Rob this is the point. Whenever I drive a unit with suspension control pad thingy I have no problems but this Scania doesn’t have one and I’m assuming that the switch down by my right knee does the same thing! But not a lot seems to happen when I switch it to the down position. As I say maybe I’m not giving it enough time.
I’m definately winding the legs down fully and definately not dropping the air before winding the legs down.
Try inflating the air before you wind the legs down then, but don’t let it go too high or else the next person that picks the trailer up will not be your mate because it will be too high for him to ‘catch’. Wind the legs down fully then, and then pull forward to release the pin (after pulling the lever), then dump the air out. Some wagons are really slow and it could take best part of a minute - I used to have an FH12 like that - it was a bloody nightmare, especially as it was used for shunting too .
(and yes, I do know how to work it before anyone 
.