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rear main cap, side seal, rear seal question

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Apologies if this post is redundant, but I couldn't find a clear answer when I did a topic search. My '72 Z has had a small, but steady oil drip from the plate separating engine and transmission (4-speed)ever since the engine was rebuilt and re-installed two years ago. The oil pan gasket was seeping a bit on the right rear corner (a popular spot, I guess), and further bolt-tightening did not resolve it, so I dropped the pan. I did the best I could to flatten out any dimples in the flange, checked it with a metal straight-edge, applied Permatex Hi-tack gasket sealer to both sides of a new Fel-Pro gasket, and torqued all bolts to 3 ft.lb.. I also slid the two rear main bearing cap side seals out (easily), coated them lightly with the same sealer, and reinserted them beforehand. Still leaked. Further torquing to 6 ft.lbs. did nothing.


Next was pulling the transmission so that new front and rear shaft seals could be installed along with a new front cover gasket and a new rear engine crankshaft seal. Still leaking.


The oil pan is off again, as there was oil seeping from the same corner as before. I pulled the two side seals again, and have new ones to insert. But, these side seals (and the ones I pulled from the engine) do not have the thin metal stiffening shim that have been discussed in other threads. They are just firm rubber, and the new ones do not even have the same stiff wire embedded in them that the originals had. MSA, where I bought them, insists these are the genuine Nissan parts, and they had never heard of the stiffening shims. Am I missing something here?


My oil pan did not have the Nissan stiffening braces that were introduced on later cars to spread the bolt torque over a broader area. I have made some of my own, encircling the flange of the oil pan, and they will be installed the next time around.


The final issue is the rear main bearing cap. Previous postings mentioned the possibility of oil leakage along the uppermost seam where the base of the cap seats against the engine block, unless this area is properly sealed with a "jointing compound" of some sort. I can't tell if this might be a source of the leak, but should I consider pulling the rear bearing cap off to re-seal it anyway? Can this cap be removed and re-installed without risking damage to the rear crankshaft seal itself? I really don't want to drop the trans again if there is a decent chance the rear seal will be displaced or damaged in the process. Any advice on this question? What material should I use to re-seal the surfaces of the bearing cap?

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