Leaking rear main seal

[Bryce Mcclintock]

Hi guys I have a 52 plymouth has a later 230 with the 3 speed  Trans . I've just done 200 miles since a rebuild and it's going well apart from a heavy leak from rear mains seal . This motor was done by a shop and I'm sure they would probably fix it if I tore engine out and took it back . Thing being I simply don't want to go to that extent if I don't have too . My question Is if I take of dust cover and oil pan and undo the rear main cap can I have a go at putting a fresh set of those rubber ear pieces try seal it up I'm sure the upper and lower halves will be fine they are the push in neoprene type not bolted in . Is this an ok thing to do am I going to upset anything buy removing that rear main ? Thanks 

[Dartgame]

I'd try and confirm if its the small rubber pieces that are leaking. It could be the split seal. Or it could be end rail gaskets (the C shaped part).

 

Yes you can drop the pan in the car and remove the rear main bearing cap. If you decide to replace the split seal, loosen the rest of the main caps to allow a little wiggle room when removing and replacing the seals. You will need to replace the oil pan gasket as well. Your leak may actually be the end pieces on the pan. Most folks that dont have a service manual dont know to leave those end rails long, I dont recall the actual length but they are supposed to sit up on each side by an 1/8 inch or so on each end.

[DJ194950]

I would do nothing until I took it to the rebuilding shop and push them to do the diagnosis of the leak. Show them the leak/leaks.

 

If It is something on the easier side then get them to at least provide the parts. Be sure that it is easy!

 

If it is the seal/s in the main cap then this is a Big job!!

 

Look at options after some more checking?

 

My 2 cents.

 

DJ

[Bryce Mcclintock]

3 hours ago, Dartgame said:

I'd try and confirm if its the small rubber pieces that are leaking. It could be the split seal. Or it could be end rail gaskets (the C shaped part).

 

Yes you can drop the pan in the car and remove the rear main bearing cap. If you decide to replace the split seal, loosen the rest of the main caps to allow a little wiggle room when removing and replacing the seals. You will need to replace the oil pan gasket as well. Your leak may actually be the end pieces on the pan. Most folks that dont have a service manual dont know to leave those end rails long, I dont recall the actual length but they are supposed to sit up on each side by an 1/8 inch or so on each end.

Ok this could make sense as in the end of pan because there is a small leak at front too perhaps they cut those rails off too short not knowing?  I did notice those pieces appeared to be too long when I ordered the pan gasket set and had a look at it before I gave it too them 

[9 foot box]

    I put the oil pan on my 57 D-300 yesterday. Dodgeb4ya posted about 5 years ago, about using short straight pins to keep the gasket oriented to the front and rear seal. I did that, with a small amount of gasket maker at 4 points under the gasket and seal. These are the old seals, you can see why they added length to the end of the seals for squish, needed for a proper seal. Rick D.

[Sniper]

I was watching Hot Rod Garage yesterday.  They had a turbo Buick Regal that was leaking oil under acceleration.  They used a smoke machine to find it.  I think when I get my 230 built I will use a smoke machine to look for leaks before I install it.  Might be a good idea for any engine build.  Heck, it might even be a good idea to test your trans too.

Edited March 12, 2023 by Sniper

[keithb7]

Many of us have had issues with the rear main seal. I've been reading threads on them for years here. After rebuilding my engine I too have a leaking rear seal.

I paid extra attention and followed steps I read about on here. I did not trim the oil pan gasket seals too short. I put a dab of silicone where the oil pan gasket side gaskets meet the rear. I pre-oiled my crank surface. I lubed the seal up. The crank seal area was polished up. Nothing worked. It leaks. I do plan to go back in there and look around again at some point.  Take another crack at it. I am intrigued by the smoke machine idea. Hook it up to the oil fill tube and force the smoke down into the crank case? Create a slight positive pressure in there (2 psi maybe) watch where and if any smoke comes out?

[Sniper]

49 minutes ago, keithb7 said:

I am intrigued by the smoke machine idea. Hook it up to the oil fill tube and force the smoke down into the crank case? Create a slight positive pressure in there (2 psi maybe) watch where and if any smoke comes out?

 

Pretty much, but don't forget to seal up the road draft tube and dipstick tube as well.

[Bryce Mcclintock]

16 hours ago, 9 foot box said:

    I put the oil pan on my 57 D-300 yesterday. Dodgeb4ya posted about 5 years ago, about using short straight pins to keep the gasket oriented to the front and rear seal. I did that, with a small amount of gasket maker at 4 points under the gasket and seal. These are the old seals, you can see why they added length to the end of the seals for squish, needed for a proper seal. Rick D.

I see yours are made of rubber or neoprene?  I'm sure the ones in my set were made of cork as well as the side pieces maybe the cork doesn't seal as well? 

[The Oil Soup]

On 3/12/2023 at 3:00 PM, Bryce Mcclintock said:

I see yours are made of rubber or neoprene?  I'm sure the ones in my set were made of cork as well as the side pieces maybe the cork doesn't seal as well? 

His look like oil soaked cork.

[9 foot box]

   They are cork and the side gaskets were probably originally .045” thick and more like a card stock or layered paper. My new gaskets and seals are cork, Fel-pro OS 4250 C. Dodgeb4ya posted this Nov.15,2018, I used 4 guide pins with a slot for a screwdriver. One hole over from end, hung the pan with a few longer bolts, then put the guide pins in the corners. If I have to do it again I will taper the ends of the pins. It will make placement of the pan easier. Rick D.

 

Edited March 17, 2023 by 9 foot box
More information

[Labrauer]

I think the pan gaskets are cork but the ones that go on the ends of the oil pan are the rubber ones. Be sure not to cut them off even if they look like they are to long. When you tighten your pan they will squeeze down into the Grove at the ends of the pan. If I remember right there is an upper one and a lower one. They are not that hard to change but can be time consuming to get them done right. Even though you may put new ones in it won't be long before the leak starts all over again. Out of all the ones I have had the pleasure of changing they all leak over time. Good luck with yours 

[Bryce Mcclintock]

17 hours ago, Labrauer said:

I think the pan gaskets are cork but the ones that go on the ends of the oil pan are the rubber ones. Be sure not to cut them off even if they look like they are to long. When you tighten your pan they will squeeze down into the Grove at the ends of the pan. If I remember right there is an upper one and a lower one. They are not that hard to change but can be time consuming to get them done right. Even though you may put new ones in it won't be long before the leak starts all over again. Out of all the ones I have had the pleasure of changing they all leak over time. Good luck with yours 

Yes seems from what you guys are saying it may just be the nature of the beast and something I'll have to just live with . Thanks again for all your input.