I know theres been threads about rear main leaks but when I want to re read them I don't find them.
I'm just about ready to give a truck back to the customer after  a restoration and the rear main decided to leak more than a drip or two,its a 312 with a fresh overhaul it had a rope in it the first go round, that leaked just on start up and I didn't like the road draft tube so I got the valley cover from John with the pcv set up in it and a best seal for the rear main, installed all of that and its been so so the rear would drip a little,I took it on a 100 mile road trip last week and it seemed to quit, bitchen, till today 4 inch puddle on the floor,I'm wondering about the pcv valve I believe I have the number written in the parts book if that could be a problem or just go back underneath and put another seal, any tips on what to do.

Thanks  Aaron

At the Top of of the Page click on Links. Click on Ted Eaton Balancing. At the Top left of His title Page there is a link for "Articles".Click on and go down the List to "Install Neoprene Rear Main Seal".The original "Best"  rear main Neoprene Seals were Orange.They were no good and had short Life. They were replaced by a Black Seal. There are still some Orange Ones floating around. Make sure the One You used was Black.

  

Thankyou
I used the black seal when I put one in and did it per best gasket directions which I think look to be the same as Teds,but I'll check to make sure, a drip or two I could live with but the small puddle is unaccetable, why it would start that I've no idea.
Thank you.

The PCV valve could be contributing to the problem.  Most of the valves used to retrofit Y-Blocks were not designed for them, so functionality is suspect.

That said, there are many places that a leak can originate and appear to be a rear main leak.  Be absolutely certain it is coming from within the bellhousing before going through the trouble to replace it again.  Those places include the oil pan gasket, oil pump pickup tube at the pan and oil pump, the oil pump, the studs in the rear main seal retainer, the oil filter or oil filter base plate, valve covers, valley cover, bolts missing from the rearmost holes in the intake flange of the head, distributor, cam plug, oil galley plugs, possibly others I'm forgetting.


Lawrenceville, GA

i recently had what i thought a rear seal on a fresh 292. TURNED OUT TO BE THE SEAL RETAINER BETWEEN THE PAN AND RETAINER. MY CURE WAS FOLLTHE RETAINIG BOLT HEADS WITH A HIGH TEMP SEALER,ALSO MADE A PLATE TO GIVE BETTER SQUASH OF GASKET(MADE SOME LONGER STUDS FOR SEAL RETAINER TO ACOMIDATE THE TICKER PLATE,ALSO GROUND PLAT TO MAKE EVEN CRUSH) IT WORKED.) THE RETAINERS WHER POORLY MADE AND HAVE LITLE SURFACE  TO SEAL BACK OF PAN. OIL RAN BACK TO CLUTCH COVER AND DRIPED OUT THE CLUTCH COVER HOLE

I have an idea.  Why not put the oil pump inside the pan?  I guess Ford eventually figured that out...

Thanks Gents, I did check pan bolts but do need to look between pan and flywheel cover,I did check all around the oil pump and fittings not that either, the pcv is kinda suspect to me because I had the engine on some abnormal high revs in the shop,this may have contributed to the leak,I don't normally run it up to  4800 rpm as its in a truck and usually I'll run it around 35 to 3800 that gives it 65 mph and I set red line on the tach at 3800.
  The bolts are in the last holes in the head,that is an odd thing, and the valve covers are sealing well they are the cast alum bird covers, but I'll recheck everything before I head for the seal.

Thank you

Looks to be the seal with the flywheel cover off I have oil flinging off the back of the crank when running,I'll also see to the pan bolts on the retainer, this engine has about 200 miles on it and last seal change I went to Delo 400 15/40 and some Lucas Zinc plus, what are you guys using for oil, multi vis or a straight weight.

20w50


Hyvinkää, FI

The retainer should have studs and the threads need thread sealer.

You will get all sorts of answers about oil so to keep it simple, just about any oil will do, with a little due diligence on your part.  If you use an oil with less than the suggested amount of zinc and phosphorous, either halve the oil change interval or use an additive.  If the oil already has adequate levels, do not add a zinc and phosphorous additive - more is not better.  You can usually find the product information sheet, which will tell you the amount of additives that are in the oil, on the manufacturer's website and if you can't find it there, you can email and ask for it.  Possibly the easiest thing to do is ask your favorite brand what they suggest.


Lawrenceville, GA