The side panels are not properly attached with the proper pivot bolts. These are a special shoulder bolt. They normally wear and break and were often not replaced with the correct replacement part. Because they are the hinge pins that the hood tips on, they must be tight enough to pull the side panels together against the ears on the front axle support and yet allow the hood to tip. I always tighten them till there is some binding and then back off just a bit. I have seen regular bolts used with a jam nut between the side panel and the ears of the front axle support. Naturally this increases the width at the bottom of the grill opening.
The ears on the front axle support where the side panels attach are too far apart. Because the ears are vulnerable to front end damage either from collisions or loader installations, they break off. If a repair did not replace them exactly as they were originally, they could be too far apart which increases the width at the bottom of the grill opening.
The side panels are distorted. Again, damage from collisions, failure of the pivot points form wear, etc. will cause the edges at the grill opening to be wider than original. Repairs could have been made that distort the original position of the side panel and thus the opening for the grill. Just like in body panel repair on cars, the repairs have to be made to restore original dimensions.
Intentional modification to accommodate implement mounting. Numerous loaders, blades, fork lifts, sweepers, mowers use the front axle support to mount their frames, drive units and pumps. It is possible that the installation of one of these items at some point in this tractors history required that the opening at the bottom of the grill area be widened. I’d look for washers or spacers inserted between the pivot points of the side panels and the mounting ears on the front axle support and remove them to restore the original dimensions.
By Robert Sybrandy