Just started driving an 8x2 Volvo FM bulk animal feed lorry with a lifting rear axle and wanted to pick your brains about it. After getting stuck in snow a few times this week Ive had to lift the rear axle whilst loaded to ‘weight’ the drive axle, now while shes loaded (or even with only 3 ton spread evenly over the body) the rear wheels dont actually lift completely off the ground… it seems like when I hit the lift axle button, it only lifts so far then cuts off. Then when the body is empty I hit the button again (still with the axle supposedly in the up position) the axle then comes the whole way up. I just wondered what stops the axle coming the whole way up when part loaded (Id assumed it would lift completely after the first half load was delivered)?
It will be fitted with a load sensor valve which will tell thetruck if it has weight in therefore dropping the axle to add to stability and to help with stopping overloading on axles
sometimes you have to wait a little while.
you lift the axle, but the excess weight on the drive axle air bags lowers the drive axle until the air builds up. scania and volvo are a pain for this, daf usually seem ok though.
Used to be called a 10 second button the first hit is to put more load on the pusher axle if it starts to spin second application is to lift the axle into the stow position.
Usually have a load sensor on third axle which operates the bags automaticaly to stop you overloading the bogeys.Most 6 legger tractors use two buttons on the dash now.
not sure about volvo ,but as mentioned some makes have a button to enable you to lift the axle for x amount of seconds so you can get drive ,also they are also speed dependent ,where for certain applications ie forrestry work the axle can stay up longer ,but when when you hit a predetermined speed on the road the axle drops ,obviously this is in a loaded condition
Usually you have to ask the Dealer to enable axle lift in “any” occasion via the ECU. Sometimes a valid reason has to be given (depends on your relationship with the Dealer) so as they are not implicated in any axle overloading case.
