Dump air??

Hello all, new to driving, new to Roro wagons, chatting today and long story short, what is meant by Dropping air from rear axle?? I know to lift axle when empty but don’t understand dropping air when loaded or how to do

HIscrapitjack,
This could be a [wind up] however i maybe 18 years out of date, but the practice i would imagine is the same. if your collecting trailers off the dock ie ro-ro, the practice is that tugs collect the trailers from the ship drive them on to the dock ie dump them and clear off to the ferry and collect another,they have no care if a driver will be able to pick the trailer up if its dropped high or low ,

however, if you know an ordinary unit is picking up the trailer like yourself and the trailer is heavy,or it is different units some with lift up axels or 6 wheel unit there is always a difference in turntable hight,well there used to be …so you drop the air out of the rear axles to take a bit of weight off the legs,that is if if you are dropping the trailer, then wind the legs down but not to the deck, leave a gap to the deck so when you drop the trailer it bangs on the deck, then when someone goes to pick that trailer up it is easy to wind the legs up as the weight is on the three aexels not on the legs.

There used to be a lever on the chassis at the rear of the trailer it moves left or right iie] one way to lift the air bags[ up] puts weight on the legs or the other to blow the airbags down…takes weight off the legs …you need to get around and get to a proper haulage job .or ask its easy …if its a wind up at lest if has given me something to do…but ask…remember everyone has been shown what to do by some one you will never find that someone but they are around good luck.dbp…

You can drop the air on the unit using the remote, also on the trailer using the colas valve at the rear of the trailer. Generally used for coupling or to level the trailer when unloading/loading

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Are you thinking ro-ro as in
ferry drop trailer? Or drop skip bodies? Both get called ro-ro.
.
If the latter what type of vehicle 6x2, or similar with a trailing axle?

Dumping air is is were you lower the rear axle on the unit or trailer sometime you will need to do it to level the the trailer for loading or unloading, for example at all aldi’s there is a steep ramp going down to the bay doors so you need to try and level the trailer or everything will roll out the back so to help stop that you lower the rear axle on the unit (dump air) and raise the trailer axle as far as you can keeping in mind the height of the bay ramp when its lowered down into the trailer, hope this helps

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I usually refer to dumping air from an axle in order to gain extra traction on the drive axle.
If there’s an axle next to a single drive axle, the weight imposed on that extra axle (on a tractor unit it’s usually a mid lift axle, but could be a tag axle behind the drive axle, less common) will not help the drive axle to get some grip on a slippery surface, so one dumps the air from that extra axle in order to transfer the weight onto said drive axle and get some grip.

This seems to be incredibly complicated these days, i’ve lost count of the number of drivers who struggle trying to reverse up a slight slope and turning the trailer (Magor services a prime example) at the same time, with the tractor drive axle constantly starting to spin, thereby cutting power*, rinse and repeat,when if they simply dumped the mid lift air the vehicle would increase grip massively.

Some might be using the term dumping air when one lowers the vehicles in order to slide under a body, or to get a fifth wheel under a trailer without scraping all the grease up the rubbing plate, but that should be termed lowering suspension, not dumping air, could be a local colloquialism at play here.

  • we’ll not mention the merits of switching off TC/ASR in order to stop power being cut when the vehicle senses wheelspin :laughing:

scrapitjack:
Hello all, new to driving, new to Roro wagons, chatting today and long story short, what is meant by Dropping air from rear axle?? I know to lift axle when empty but don’t understand dropping air when loaded or how to do

Im guessing, with your user name, your talking about hook loader roll on roll off skips with scrap in? I youve got stabiliser leg or axle locks, dumping the air make the truck sit solid on them when loading/off loading.
With out leg or locks, without dumping the air, as the skip slides back the truck increases the pressure in the air bags to try and keep the truck level, potential to cause damage with the large loads on the rear axles, if the skip touches the ground quickly the truck will then try and rise up quickly with the extra pressure in the air bags, then sensing its too high will release the pressure to bring the ride height down, and the top of the hook getting hung up on the eye of the skip, as you pull forward you either wheel spin because the air bags have now deflated, and you not got enough weight on the tyres, or you pull forward and the back end of the truck drops to the stops, (this is all extremes).
Some manufactures/installers program the truck to dump the air automatically when the pto is engaged.
There will usually be a remote control on a curly lead, turn it on and press and hold the down arrow, or maybe a preset button to dump the air, or the may be a button on the dash, Remember to reset the ride height when finished.
If your not driving a hook loader please ignore me :laughing:

6 replies to scapitjack and he has not commented, where has he gone, [wind up]?

peggydeckboy:
6 replies to scapitjack and he has not commented, where has he gone, [wind up]?

Probably got a job, and a life? Dunno, beats hanging around this place all day every day

mardybum,
you sound as if you are ,once you have done your full years up the road you will get to like hanging around doing sweet F-all it seems from all of your posts you have had plenty of jobs and experience.
we will keep a seat for you for 20 years time lol.air bags or not.

scrapitjack:
Hello all, new to driving, new to Roro wagons, chatting today and long story short, what is meant by Dropping air from rear axle?? I know to lift axle when empty but don’t understand dropping air when loaded or how to do

If you mean roll on off then don’t dump the air as it’s possible that with a fully weighted body you could eventually rip the rubber bump stops of the rear axle as in break the bonding .

Punchy Dan:

scrapitjack:
Hello all, new to driving, new to Roro wagons, chatting today and long story short, what is meant by Dropping air from rear axle?? I know to lift axle when empty but don’t understand dropping air when loaded or how to do

If you mean roll on off then don’t dump the air as it’s possible that with a fully weighted body you could eventually rip the rubber bump stops of the rear axle as in break the bonding .

Well said there Dan The Man, Hope you are keeping Well My friend, Regards Larry.

Don’t roro skip wagons still have the stabiliser wheel at the back, should be no need to drop all air with the stabiliser dropped.