Genuine Buick Century Crankshaft Seal

Buick Century Crankshaft Seal Parts Questions & Answers

• Seal Assembly, Crankshaft Rear Oil
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  Q: How to remove and install the lower half of the rear main bearing seal on Buick Century and Regal?

  A: To remove and install the lower half of the rear Crankshaft Seal on Buick 231, 252, and 350 engines and Oldsmobile 307 engines, first remove the Oil Pan and rear main bearing cap. The old oil seal should be taken off from the cap of the bearing by applying a sealer to its groove. Thereafter use a suitable instrument to roll a new seal into the groove with both ends extending above the surface where cap parts. The working surface of the rope seal should be coated with thin film of chassis grease before being driven into the groove using a smooth tool or hammer handle such that it is not more than 1/8 inch (1.5mm) above this groove. Slightly rotate the tool to cut off those ends of seals which are flush with surface of caps using a razor blade. Soak new neoprene side seals for Buick 231, 252 and 350 engines in kerosene for five minutes, then place them in grooves on bearing caps without cutting them to fit. A sealer must be applied to mating surface of bearing cap between it and block around sealing groove. Reverse steps of removal when installing pan and cap back on. At first run engine at low rpm after new seal is installed. For upper half replacement of oil seals on Buick engines, though advised that crankshaft be removed, crankshaft may remain in place during their replacement.Loosen other crankshaft bearings so that crankshaft comes down about 1/8" (0.062 mm).Lube new seal with oil (for 1975-84 vehicles) or chassis grease (for 1985-87 vehicles) lubricate an old one.Remove excess seals if necessary.Pull each side equally.Replace all bearings; tighten all bolts according to specifications before attaching rod bolts.Chevrolet engines' oil pans, pumps and rear main bearing caps are all removed.For instance, tap upper seal slightly, and pry lower seal out through it.Clean all mating surfaces before installing new seals using a lubricator to place the lip of the seals forward.The installation tool should be used to prevent damages upon the seal by guarding the crankshaft while working around it. No oil should be present on mating surfaces so that one can replace oil pan, pump, and run engine in order to break in new seals.In case of 265 and 301 Pontiac engines, this involves removing the oil pan and baffle, rear main bearing cap, and forming a new seal in the cap.After driving the upper seal into groove on each side until it is packed tightly.Afterwards take pieces from new seal, cut them into lengths slightly longer than required to fill gaps at end of block's portion of said seal; then insert them packing these tightly.None must be trimmed. Apply a 1/16 inch bead of silicone sealer from center of gasket across to external gasket groove.Reassemble the cap and tighten bolts according to specifications before refitting oil pan.Finally run engine slowly for first few minutes so as to break in new seal.The upper oil seal can be replaced without removing crankshaft on 263, 350 and 403 Oldsmobile engines.Drain crankcase; remove oil pan and rear main bearing cap.Therefore drive upper seals on both sides till they are tight.Then cut these pieces little longer than necessary for filling grooves and stuff them into these grooves.Place shim stock between the seal and crankshaft before trimming any protruding material from surface of bearing without leaving scratch marks.Put another one in cap.Reinstall this alongside its bolts that will need specified torque values.Last but not least, refit oil pan.