Mystery Solved: Rear Wheel Cylinders 65-69 vs. 70-75
The model years mentioned in the title of this thread call for different part numbers but all the specs (including hydraulic specs) are identical in each piece.
Today I attempted to replace a rear wheel cylinder on the '65 Formula S where a previous owner swapped in a 489 case 8 3/4 differential. Although the wheel cylinder indicated for the '65 looked identical to the wheel cylinder I removed, I ran into one subtle difference: The fastener bolt diameter in the cylinder I removed was 1/4" and the threaded holes for the '65 wheel cylinder are larger. Fortunately, I had ordered a pair of rear cylinders for each production period and found the 70-75 version has the smaller (correct for me) diameter threaded hole. Hopefully this information will help another Mopar brother some day.
The model years mentioned in the title of this thread call for different part numbers but all the specs (including hydraulic specs) are identical in each piece.
Today I attempted to replace a rear wheel cylinder on the '65 Formula S where a previous owner swapped in a 489 case 8 3/4 differential. Although the wheel cylinder indicated for the '65 looked identical to the wheel cylinder I removed, I ran into one subtle difference: The fastener bolt diameter in the cylinder I removed was 1/4" and the threaded holes for the '65 wheel cylinder are larger. Fortunately, I had ordered a pair of rear cylinders for each production period and found the 70-75 version has the smaller (correct for me) diameter threaded hole. Hopefully this information will help another Mopar brother some day.
