500 MILES WEST OF FLINT
By Al ‘Junior’ Malachowski
The next time you find yourself crawling around under your Skylark or having it serviced on a lift, spend some quality time checking out the results that thermal expansion of the rear axle gear oil might have contributed to around the rear differential carrier, axle housing, and rear wheel backing-plate assemblies. Notice any oily wet films or caked-on road dirt accumulating after losing some of the four pints of 90W gear oil? Just a heads-up: before you attempt to verify the gear oil level, be aware that a stinky oil shower is predictable and avoidable unless precautions are taken to remove the pressure buildup before removing the filler plug or one of the cover bolts completely. Think of the assembly as a whistling tea pot on two wheels that can’t whistle. In short, the gear oil volumetric size changes with a change in temperature, thus creating a built-up pressure that needs to find relief somewhere. Repeated heating and cooling cycles don’t help on the serviceable parts either.
Telltale signs around any of the twenty-five bolts (lacking a thread sealant?) securing the torque tube to the differential carrier to the axle housing to the housing cover, pinion bearing sleeve lock screws, gaskets, mating surfaces, filler plug, or rear wheel oil seals could confirm that some type of pressure relief for all 1953 and early-1954 Skylarks may be a good idea after sixty-something years. After building seven million-plus Buicks, the engineers at Buick Motor Division finally came to the conclusion that it would be a good idea too. Starting around June 1, 1954, about the time 1954 Skylark Body #672 rolled off the Flint assembly line, a change in production of the rear axle housing incorporated a bobble-head type breather vent above the left rear axle, topside of rear axle housing, 14” maximum from centerline of the housing cover. This change is addressed in the Buick Product Service Bulletins and pictured below, suggesting the following procedure for adding a breather vent to your already-assembled rear end assembly: removal of the left axle and ring gear then stuffing a greasy rag in the housing to catch the metal shavings while drilling and tapping the hole. Can’t find the OEM part? Similar aftermarket breather vents from Dorman (924-262) or Currie Enterprises (9028) should do the job and are available from your FLAPS. Maybe a better idea yet and an easier install would be to replace one of the 3/8-24x1/2” axle housing cover bolts near the 11, 12, or 1:00 locations with a 90°-elbow fitting and breather vent if you could find the right combination of parts; maybe not. After all is said and done and cleaned up, refresh the OEM car look by spraying another coat of red oxide primer on the differential carrier while you’re under there.