Rear Main Rope Seal

[Racerstev]

Hi all, been chasing some small leaks on my 39 P8. Seems I have 2 to either deal with or live with. 

 

1st off is the rear main. For sure someone has been in there, seems to have some black and red silicone up there around the sheetmetal 

retainer. I have never done a rope seal so looking for advise on the replacement. 

 

I'm a tech at a Toyota dealer so I have some knowledge and experience, just not with anything this old. From what I can tell the pan comes off,

the rear cap comes off, you remove the upper seal with the crank in place with a "corkscrew" tool (Lisle 27000 sneaky pete tool). Reinstall with a long cable with a clamp on the end. 

For the cap it looks kinda straight forward, just seat the seal in the groove, cut the seal flush with the cap and seal with sealer.   

 

Ok sounds easy right? Please any tips would be a huge help! 

 

2nd leak is the trans, seems were the shafts come though the case there is no seal, oil just slowly oozes out. 

Is it safe to put a sealer on these holes? 

 

Steve 

[andyd]

Welcome aboard from Oztralia...when I did the rear seal on my 1941 Plymouth 10 yrs ago I had a nice complete Best gasket full gasket set that had the 2 type of neoprene seals so thinking that it had on the original 1941 engine the rope seal I obtained one.......when i got into the job I discovered that the car had one of the neoprene seals but more importantly a previous owner had not installed the small side seals that go between the main cap & block...........lol.......just a small gap but enough for oil to weep out............lol.........there are two different shaped side seals .. .............If at all possible I would actually check what is there first then order what you need, also when installing the sump pan seals do not trim the front & rear pan gaskets as they are supposed to be left a little longer than what you might think to allow for compressing the gasket when the pan is bolted up........I installed the side seals & most of the leak stopped.........lol..........andyd

[Sniper]

 

[Sniper]

Some thinking or replacing a rope seal

 

 

[Racerstev]

Good reading and very helpful. Seems the large cookie sheet is the answer! I have 1 smallish drop on the garage floor from both the engine and trans after a hour drive. I can live with it, if the engine ever needs to come out i’ll deal with it. 
 

i’ll try a little rtv on the shafts of the trans. 
 

Steve

[Sam Buchanan]

One drop???? I wouldn't touch that rear seal!  ?

[Racerstev]

Sometimes it's hard to figure out what to chase and what is just a 30's thing. One of the reasons I love this old girl, 

I learn everyday!

 

Steve 

[LeRoy]

14 hours ago, Sam Buchanan said:

One drop???? I wouldn't touch that rear seal!  ?

I've got a coffee cup under mine that holds most of what drips out overnight.

Edited February 15, 2023 by LeRoy

[Booger]

Speedee sleeve and new seal should fix the shaft leak

[Racerstev]

Do they make 2 piece sleeve's? It  would need to fit around the flywheel flange. At this point I have no idea if the crank is worn or not. 

 

Also, can I use the newer rubber seal instead of the rope seal? They look to have the same bolt pattern.

 

 

Steve

[Sam Buchanan]

5 hours ago, Booger said:

Speedee sleeve and new seal should fix the shaft leak

 

If you are referring to the crankshaft that ain't a possibility. The flywheel flange makes it impossible to use a Speedi-sleeve, which are only one-piece.

[andyd]

Racerstev..........my 1941 Plymouth should have had a rope seal.....the rear main was leaking badly and all I had was a nice new Best brand full gasket set with both types of neoprene seal.......so I bought a rope seal.......then pulled the sump & rear main cap off only to discover that this 1941 P11 stamped 201 cube engine that should have had a rope seal in fact had a neoprene seal, which didn't appear to have much wear on the seal edge..........BUT it had NO SIDE SEALS, there are 2 different shaped side seals that fit between the main cap & block......my engine had neither.....lol...........so I installed the right pair and whilst the engine still marked its territory a bit, the side seals stopped the majority of the leak.........I would check whats actually there first.......lol...........andyd.

[Racerstev]

So it seems the 2 seals can interchange. I saw the 2 side seals that come with either main. From what i can see the oil seems to be passing the main not the side seals. But still room is limited so i can’t be sure they are there. 
 

i think i need to investigate. At best i would need to remove the flywheel to replace the upper seal, bolt access looks very limited with it on. Btw, the engine number indicates mine IS a 1939. 
 

steve

[Booger]

On 2/16/2023 at 8:24 AM, Booger said:

Speedee sleeve and new seal should fix the shaft leak

refering to tran leak

[Sniper]

There is no seal on the input shaft.  I posted a link to how it is addressed.

[DonaldSmith]

Rear seals are far from perfection.  My dad had a new 1952 Cadillac that dipped a little.  Cadillacs were not supposed to leak.  He complained to the dealer, but the dealer showed him that every car in the showroom had a pan under it.  

[andyd]

As I mentioned I'd drop the pan & main cap and only then decide which part it should or does have.......lol............andyd 

[Racerstev]

10 hours ago, Sniper said:

There is no seal on the input shaft.  I posted a link to how it is addressed.

Mine is leaking from 3 places. In the rear at the 2 shafts with the bolt in retainer. The front were one of the 2 shafts come though. And the top were the shift cable and linkage go in, the gasket is leaking. I’m very pleased that the input and output shafts are dry. 
 

Going to drain the trans, clean things up, seal the shafts and replace the gasket.  Ordered 2 quarts of stalube gl4 140 weight oil. 
 

Steve

Edited February 19, 2023 by Racerstev
Oil update

[DJK]

11 hours ago, Racerstev said:

Mine is leaking from 3 places. In the rear at the 2 shafts with the bolt in retainer. The front were one of the 2 shafts come though. And the top were the shift cable and linkage go in, the gasket is leaking. I’m very pleased that the input and output shafts are dry. 
 

Going to drain the trans, clean things up, seal the shafts and replace the gasket.  Ordered 2 quarts of stalube gl4 140 weight oil. 
 

Steve

GL1 is required in these transmissions to protect the brass components.

[Sam Buchanan]

And an even better oil than GL1 is Redline MTF or MT90. These make the syncros work the way they were intended and won't degrade them like a modern GL oil.

 

[Racerstev]

I read though the debates on Gl1 vs Gl4 vs Gl5. What I learned is Gl4 can be used in cars with brass synco’s. 
 

I agree Redline MTL and MT 90 is awesome , I use it in my MR2 and it made a huge difference. Now on my old girl I don’t see shift speed being an issue. I was trying to get a modern lubricant with close to the right weight. The book calls for 175 wt. 

 

Now just to confuse us some more…

 

 

[Racerstev]

So, we have a GL5 that’s made for manual brass tranny’s. Have the same weight GL5 that’s for rears and a GL4 that for brass tranny’s… 

 

I like the 175w140ns.. but $24 a quart is tough..

 

steve

[Sniper]

I changed out my rear and trans oil not so long ago.  I have no idea when it was last changed, but the old stuff looked good coming out.  As rarely as the stuff needs changing I don't think $24/quart would bother me. 

[Sam Buchanan]

First time I changed transmission oil in my '48 P15 I used whatever was on the shelf at the local auto parts store, think it was GL4. Then the shift from 1st to 2nd with a cold trans got crunchy. That is when I did some homework and found the modern GL oils are too "slippery" for good syncro ops. In spite of being skeptical of "repairs in a bottle" the switch to RedLine instantly solved the shift issues, it is now smooth at all temps. Knowing the syncros are also happy is worth the extra $$$$'s to me.

 

The diff has GL4 oil, no brass parts or syncros to worry about there.

Edited February 20, 2023 by Sam Buchanan

[DJK]

On 2/19/2023 at 2:37 PM, Sam Buchanan said:

And an even better oil than GL1 is Redline MTF or MT90. These make the syncros work the way they were intended and won't degrade them like a modern GL oil.

 

That is what I use due to the GL 1 rating.