We have a daf 6 wheeler rear lift which was a stretched 2 axle tractor unit with Granning rear lift,it was done for the previous owner by a well known converter ,I weighed the axles before it goes on the road with a nice palleted load taking it to 24’500 gross so just a bit light,the front axle is near max not that it’s the issue here ,the drive was 8900 (11’500) and the rear lift 8300 max(7100) ,the problem is there is no manual adjustment of the air to the bags in either axle.we contacted the converter and said I think we need to fit a manual pressure reducer with quick release valve,he said no you don’t it’s a laptop job,so we contacted Granning who said we do need to fit a valve ,I am wondering how many more of these conversions are running about like this ,I heard of one similar .obviously if it was a factory build it would be adjustable via the laptop,if you have a converted 6 wheeler it could be worth a quick check weigh.