rear main sealant

[Dave WM]

https://www.permatex.com/products/gasketing/anaerobic-gasket-makers-flange-sealants/permatex-anaerobic-flange-sealant/

for this the two places one on the block where the rear main bolts and some on what looks like the inside groove of the bearing cap where the rubber side seals go. Not it give very specific coverage areas, but the illustration leave a bit unclear on the bearing cap, I ASSUME its just applied to one side of the groove.

 

I search and search and searched, seems so many conflicting info, thought I would bring it up again.

Edited November 21, 2016 by Dave WM

[gwri8]

I haven't ever used any sealant for the main seals,  a little grease maybe when you tap them in, but not anything extra. Then again, my rear seal leaks a little, not much.

 

[Zed Head]

Are you replacing the rear main bearing cap seal, or just the round crankshaft seal?  Or both?

[Dave WM]

Zed Head, I have a leak, seems like it could be pan gasket, but not sure. Its the pass side, rear of the pan, does not look to be from the weep hole of the bell housing but not sure about that.

I have ordered the rear main seal, the side seals, and a pan gasket (all OE Nissan). should be here in about a week.

Since I plan to pull the trans anyway to swap in the 5 speed, I was thinking the seal maybe the source of the leak. Much of my research has folks saying replace  anyway if I am already pulling the trans. So the rear main for sure. I was thinking as long as I am pulling the pan to see if the gasket is the issue I may as well replace the side seals. So I do plan to do all but maybe not a the same time.

I was thinking of the pan and side seals 1st just to see if that stops the leak. When I pull the trans it would be a good time to inspect the clutch/flywheel/rear main, I assume I will be able to look at it and determine if the seal is leaking but as mention before even if not I suppose it makes since to replace it, unless it looks brand new. I figure I will know better once its apart.

the plan is to replace the clutch and get the flywheel machined or replace with new.

found these videos that were helpful.

clutch

rear main

 

 

[Dave WM]

Note for some reason he does not use the lithium grease but rather just reg motor oil. I would follow the FSM and use the lithium grease. the video is good as a reference for what it will look like once I get in. the FSM has illustrations I prefer seeing actual pictures or in this case video.

I also edited my orig post to make it easier to see the specific area I am trying to get the sealer for, added the pic instead of the link.

 

Edited November 21, 2016 by Dave WM

[sweatybetty]

my 2 cents.... you need some sealer where the main cap meets the block, between the side seal and the crank case, just like the pic you posted.

[Diseazd]

Dave....The flange sealant you showed should work perfect for where the rear main bearing cap meets the block. But, IMO the side seals never leak if properly installed in the first place with proper sealant on the flanges. Besides, that's a PITA job with the motor in the car. The most likely source of your leak is the rear main seal......an easy installation......you can use oil, grease or lithium grease to install the rear seal. Rotate the seal clockwise slightly while pushing it on the crank .....make sure it is perfectly square to the crank journal when all the way installed.

 

 

 

[Dave WM]

if the source of the leak is more likely to be the rear main than say the pan/side seals, then it would make since to alter my order. I will do the trans swap and replace the rear main.

Only if the leak persists will I then do the pan/side seals. This order makes since as I KNOW I have to pull the trans for the swap, good time to do the rear, while the pan gasket/side seal is optional.

[Diseazd]

You got it......that's exactly what I would do....I've never had the side seals leak in all of the Z's I've owned and built. The rear main seal is the culprit almost always, followed by the pan gasket. Good Luck ole boy!

[Dave WM]

hope to get to it in the next month. Been waiting for cooler weather. the attached video above really showed me just how badly the seal can leak.

Edited November 21, 2016 by Dave WM

[Zed Head]

Check the mating surface on the crankshaft for wear.  I have an old 240Z propeller shaft with a groove worn in it from a bad seal that didn't get replaced.  The metal spring inside can actually break through and contact the sealing surface if it gets bad enough.

[Dave WM]

will do ZH. If that is the case I understand there are two options:

1. Displace seal slightly so lip rides on undamaged part of crankshaft (fabricate a spacer wire to hold off lip just a bit, sounds dicey, or perhaps a fixture that would allow for incomplete but accurate driving in of the seal to displace outward slightly with out a wire to act as a spacer). Not sure about either of these approaches as the need for the seal to be driven in square could be comprised.
2. Use a crankcase sleeve.

Lets just hope it does not come to that.