Replacing my first 40 clutch and ordered a new rear main crank seal to put in while I was at it....got it in and it fixed the leak there but I still have oil around one of the bolts on what I guess is the crank bearing cap bolts? What's the best way to fix this leak? Safe to remove the bolts without f'in anything up? Is there a gasket underneath I can replace or use gasket maker?
More fixin oil leaks!
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M5driver
MUD Addict (Ret.)
Have you looked at the metal core plugs that are hidden by the bell housing? I have had the leak you describe for a couple of years and could not figure out where it came from, until someone on this forum mentioned it. I looked at mine while i have the engine out, and sure enough, two tiny leaks. These plugs will be replaced before everything is buttoned up back there, and maybe I'll have a leak-free 40 again. For awhile
Just a thought...
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- #3
Have you looked at the metal core plugs that are hidden by the bell housing? I have had the leak you describe for a couple of years and could not figure out where it came from, until someone on this forum mentioned it. I looked at mine while i have the engine out, and sure enough, two tiny leaks. These plugs will be replaced before everything is buttoned up back there, and maybe I'll have a leak-free 40 again. For awhile
Just a thought...
Nope I didn't, do I have to remove the bell housing to see them? There isn't any oil inside the bell housing though, but one bolt head just below the rear main crank seal always has oil dripping from it. Tried to tighten it up a bit but couldn't really get much of a turn on it at all.
M5driver
MUD Addict (Ret.)
Yep. Bell housing has to come off to check them.
This sounds precisely like what I have going on. As soon as I have the engine back in my chassis and get it home, I'll be changing those plugs. I have all the other leaks at the rear buttoned up. I still need to replace the timing gear cover gasket, too, but I guess I can't complain, since it lasted 30 years
I am confused about your reference to the rear crank cap bolt dripping. Those bolts are enclosed/covered by the oil pan. They should drip oil.
Here's some pix. I had leaks from both plugs.
Ed - in the picture you can see one of the the bolt heads on the right. What he's talking about really holds the rear main seal. My oil pan is still on - you can see the red jack holding up the back of the engine.
Also - while you're in there, drop the engine down and check on the freeze plug that is between the firewall and the rear engine block. Mine was nearly rusted through - I got it just in time.
Ed - in the picture you can see one of the the bolt heads on the right. What he's talking about really holds the rear main seal. My oil pan is still on - you can see the red jack holding up the back of the engine.
Also - while you're in there, drop the engine down and check on the freeze plug that is between the firewall and the rear engine block. Mine was nearly rusted through - I got it just in time.
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- #7
In the last pic, the 2 bolts that point down just below the fly wheel bolts .....thats where I have oil dripping from, particularly on the one in the bottom right corner (passenger side). I guess I will pull the bell housing and take a look, see if it's coming from the plugs you mentioned. Thanks.
Hopefully that's my problem.
Hopefully that's my problem.
OK, I'm with you now. Those rear-most two of the 4 main cap bolts are outside the oil pan, the rear of which rides in a groove in the cap.
I suppose you could retorque those bolts, but I would bet that your leak is the pan gasket itself. It could also be coming from above, of course.
I suppose you could retorque those bolts, but I would bet that your leak is the pan gasket itself. It could also be coming from above, of course.
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- #9
Yep! Those are the bolts right there!! I have a strong suspicion the leak is from the oil pan gasket right near those bolts now. But I will still check the plugs you mentioned behind the bell housing while I have it all apart. How hard is it to change a pan gasket with the bellhousing and transmision in place?? I might button everything back up to get her rollin again and just change the pan gasket later on because I will definitly have to order one.
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- #10
Found the sources of my leaks, turns out it's coming from my side engine cover bottom left corner. Managed to tighten a few screws on it and we'll see what happens. If that doesnt fix it I guess I will have to replace the gasket. Also seems to be a slight leak from the base pan gasket right under the rear main engine seal. At least i fixed the rear main seal! Thanks for the help guys!
M5driver
MUD Addict (Ret.)
If you have it apart still, it is worth checking those plugs. I fought the "must be the rear of the pan gasket/rear main seal" leak for 2 years, and would never have thought to check those plugs if I had not seen it here. After replacing the rear main twice, the pan gasket twice, and the pan, I still had the leak. Now I know where it was coming from, and it will be fixed before everything goes back together. YMMV.
I'd be suspicious of the cam plug there with the oil puddle in it, too. And, you can have oil leaking down from the rear of the valve cover easily enough as well. It's a booger to tell if that's leaking when everything is back together.
I've had the side cover leak (along with all of the others) as well. It can be frustrating to get it closed, because those covers get bent.
As far as changing the pan gasket, the hardest part often is getting it off, since that cork can really get stuck. Once you go to replacing it, as long as the oil pan isn't warped, the most important thing is keeping the sealing surfaces oil free until you get everything together.
There's a nice writeup on side cover and oil pan gasket replacement from Steve/Poser here:
https://forum.ih8mud.com/40-55-series-tech/78749-oil-pan-side-cover-gasket-stuff.html
I've had the side cover leak (along with all of the others) as well. It can be frustrating to get it closed, because those covers get bent.
As far as changing the pan gasket, the hardest part often is getting it off, since that cork can really get stuck. Once you go to replacing it, as long as the oil pan isn't warped, the most important thing is keeping the sealing surfaces oil free until you get everything together.
There's a nice writeup on side cover and oil pan gasket replacement from Steve/Poser here:
https://forum.ih8mud.com/40-55-series-tech/78749-oil-pan-side-cover-gasket-stuff.html
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- #13
Cool link, will come in handy for sure! I am still gonna check those plugs behind the bell housing like you suggested......might actually pull it off today and look. The rear screws on the side cover were pretty loose too, managed to tighten them up almost a full turn. I doubt that will make a big difference though. If I get a chance I will snap a couple of pics.
