1.  Field of the Invention
The present invention relates to a method for coating automotive vehicle bodies and, more particularly, to a method for coating an automotive vehicle body with a floor member mounted to a reverse bottom surface of an upper vehicle body section. 
2.  Description of the Related Art
As disclosed in Japanese Patent Laid-open Publication (kokai) No.  61-163,297, automotive vehicle bodies with their floor member mounted and connected to a reverse bottom surface of their upper vehicle body section are conveyed in a coating line section of vehicle body assembly line by the aid of conveying means such as hanger conveyors or the like and immersed in a paint vessel, containing an electrodeposition paint, to form an undercoat, such as electrodeposited coat film, on the surfaces of the vehicle bodies.  The vehicle bodies are then subjected to the formation of an undercoat member as a protective coat member with an undercoat member material on the reverse bottom surfaces of the floor members, as disclosed in Japanese Patent Laid-open Publication (kokai) No.  61-4,562. 
In coating the vehicle bodies with an undercoating paint and with an undercoat member material in the coating line section of the vehicle body assembly line in such a state that their floor members are connected to the reverse bottom surfaces of the upper vehicle body sections, this arrangement suffers from the disadvantage that the upper vehicle body sections covering the top surfaces of the floor members may interfere with the operations for covering holes formed in the floor members with hole covers, for coating connections of panel members constituting the floor members with a sealer, and for setting a melt seal member on the top surfaces of the floor members. 
It is considered, hence, that the operations required to be conducted prior to the conveyance into the coating line section, such as the operations for setting the hole coverings for the holes and so on, can be performed with ease by conveying the upper vehicle body sections and the floor members separately during the period of time when mountings including interior units, such as seats and interior trim members, are to be mounted to the vehicle bodies in a unit assembly step after the upper vehicle body sections and the floor members have been molded.  The separate conveyance of the upper vehicle body sections and the floor members into the coating vessel containing the electrodeposition paint for undercoating presents the drawbacks that the coating operations become complex and coating costs become expensive.