I would try cycling it a few times to see if it helps. I have an older style Brandt that has a valve on top of where the boom pivots with a lobe which stops the boom from going out too far. When the boom gets to that position it trips the valve to stop the boom from going out further. The boom must then come all the way back in to reset before it will go out again or you can manually trip the valve on top to get the boom to go out if it is in more than you want. Mine was not wanting to stay where it should a week ago so I took some WD 40 and sprayed the valves and the roller down and it has worked properly since. Maybe chemical has drifted up and made yours sticky if you have that setup. The newer Brandts from what I understand did away with the valve and have a different setup to stop the boom in position so I am not familiar with how they work.