If the kit is the type using pneumatic hose, the elbows are likely to be to replace the existing axle breather valves. Unscrew the valve and screw the elbow in. Run the hose along the axle (using the ever present cable ties!!) to a suitable point to 'jump' across the the chassis. Make sure there is enough slack for full axle articulation. Then as high as you think necessary. Mine ends at the top of the engine bay with the gearbox breathers.