BUICK Dealer Pinion Depth Setting Tool. 1930's and Up. Tool #J-681-A.

[Jolly_John]

This is an original BUICK Dealership Service Tool for rear end work. It enables the mechanic to set the depth that the pinion engages the ring gear. This is BUICK service tool #J-681-A. It uses a built-in micrometer to gauge the setting. Very well-built.

 

This tool has a brass plate on it covering the specs for 1931 to 1936 BUICK's. However, I looked in a few late 1930's BUICK shop manuals I have, and the same tool was shown in the rear end section. The depth specs were covered. So, this tool should be usable on a wide range of BUICK years. I spotted a very similar-looking tool online that was being used on a 1953 BUICK. I've included a photo from the 1938  BUICK shop manual showing this exact same tool.

 

This original BUICK pinion depth setting tool looks to be complete, and in useable condition. However, because of its age, it is being sold "as-is".

 

The price is $125, plus the shipping. Thanks for looking. John

Edited July 3, 2020 by Jolly_John (see edit history)

[old-tank]

1955 service manual references the same tool.

[Jolly_John]

Thanks for chiming in with some good info old-tank. And Lamar, instead of all of this "like" stuff you've been doing.....why don't you step up and buy something I'm selling?!!!  A happy Fourth of July to all. John

[Bloo]

I also have one of these tools. While it is true that you can use this clear up into the 1950s (or more), there is another piece, a hypoid adapter, not shown in the photo needed if you are setting up hypoid style gears.

 

To the best of my recollection, the tool will work as shown on all up through 1936, and through 1937 on Roadmaster and Limited only. Anything newer would need the adapter.

 

My tool has update sheets in the box up to 1941 or so. This info is also in the shop manuals and goes much much newer, as previously pointed out. Buick also had a newer design tool later on, but the only real difference was the micrometer counted the opposite direction, so you add where you would have subtracted and vice versa. The newer service manuals explain it all. Either tool requires a hypoid adapter to set up Buicks newer than the 1936-37 era.

 

 

[Jolly_John]

Thanks for checking in with that good information, Bloo.

 

I just looked at the 1938 BUICK shop manual, and the 1939 supplement shop manual again, and now see the written reference about use of the hypoid gear adapter you mentioned. However, the adapter is not pictured. It would be interesting to see what this adapter looks like. Perhaps it could be easily made, which would extend the useful year range of the BUICK pinion depth setting tool I'm selling. John

[Bloo]

Here is the doohickey used on the newer cars. It's dimension is 0.888" between flats if you want to make one.

 

 

 

Edited July 6, 2020 by Bloo (see edit history)

[Bloo]

There are a couple of ways a pinion can be marked. Buick's way was to mark the pinion in (+) and (-) thousandths of an inch from the default measurement. A common way aftermarket manufacturers do it is to mark the pinion with the actual distance from the center of the carrier bearings to the face of the pinion.

 

Aftermarket tools for this job (about $600) have a dial indicator, making it easy to use the markings on an aftermarket ring and pinion. To use Buick's parts with the modern tool you would have to know the actual dimension. Maybe it is in the service manuals, but I don't recall seeing it. When I bought my J-681-A I was trying to set up an aftermarket gear set in a Pontiac. I had a machinist verify that it still agreed with it's test stand (thats like the other piece in Jolly_John's pictures), and then measure it to get the basic dimension of the tool at zero. That dimension is 4.176" from center of bearings to the face of the pinion. Using the hypoid adapter (0.888"), it would be 3.288".

 

With that knowledge and some math you can use this tool on aftermarket gears, and also non-Buicks, as long as the carrier bearing outer diameter is 80, 90, or 100 millimeters.

 

Edited July 6, 2020 by Bloo (see edit history)