Read Screen-All, Seal kit for hydraulic shaker motor, part number 77801, used only on the RD-40 screen.Read Screen All, Seal kit for the hydraulic shaker motor, Part number 77801. This part is not listed in the Read parts manual but is for item number 1 in the parts drawing. Pay close attention to the drawing, the drawing is very true to the shape, thru the years as these machines get older hydraulic motors and pump have been changed out to other brands your motor should look like what's in this drawing otherwise its a good chance that this seal kit