Posted by Clint Dixon on Tuesday, August 14, 2001 at 8:40PM :
I was outside earlier today crawling around under my '47 WDX and '51 B3PW comparing the minute differences between the two trucks. I have owned several Power-Wagons spanning these general years of production and have been well aware of the differences in the way the cabs mount to the frames.
On the earlier trucks, the cab mounts at each front corner to the corresponding frame mounted cab hold down bracket using, as spacers between the cab and bracket, one 1-9/16" wooden block and one 3/8" fiber pad per corner. The rear cab corners simply rest on their corresponding frame mounted cab hold down brackets using, as a spacer, a single 3/8" thick fiber pad per corner. All corners, except for the driver's side front, use a spring loaded mounting bolt to allow for flex between the cab and frame. The driver's side front corner uses no spring in order to provide for a rigid mount at that point. This rigid corner mounting is designed to prevent binding and flexing of the steering column, brake, and clutch pedals as the truck traverses uneven terrain.
The later cab mounting system employed the use of cylinderical shaped rubber insulators with bushings through their centers and flat washers at their ends as cushions between the cab and cab hold down bracket. These were used both front and rear. The spring was discontinued at this point with the rubber insulators now providing the needed flex.
Today, for the first time, I noticed that the rear cab hold down brackets on my '47 mount with their lower edge approximately 1-5/8" above the lower flat of the frame rails. The rear cab hold down brackets on my '51 mount 3/4" lower on the frame rails. This difference allows for use of the thicker rubber insulators in place of the earlier fiber pads. The change was made possible with the relocat1on of the holes in the frame side rails. The later holes being stamped 3/4" lower than the earlier ones. My '51 parts manual confirms this. The frame rails changed at serial #83919652 Detroit built and #88766163 San Leandro built. Also changed at this time were the cab hold down brackets. I have yet to determine exactly what changes were made in these at that time.
I have owned Power-Wagons for over 20 years, and continue to find details on them and in the manuals that I have never noticed before.
Grandpa told me that I would learn something new every day!