The question usually applies to the following Malabar mobile axle jack models: 50P9AR, 60P9, 60P10, 65P9AR and 65P10AR. On models manufactured prior to September 1995, the jack reservoir was bolted to the frame. Over time, this configuration may loosen due to towing or other in service conditions causing the air pump/reservoir gasket to fail. On current models, the reservoir and frame are welded together, eliminating the use of bolts. For all units in service prior to September 1995, we recommend welding the connection. For additional information, please contact email@example.com.