rear main seal info

1941 - 1945, MB, GPW Technical questions and discussions, regarding anything related to the WWII jeep.
fiveftsix
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Re: rear main seal info

Post by fiveftsix » Sun May 17, 2015 3:12 pm

Having got to the stage of driving a GPW so as to eliminate any issues now find it has a leaking rear main,it also had the pistons and rods and the oil rings incorrectly installed too, which I corrected earlier.
On pulling the crank I have found it to be fitted with the dreaded 800093 seal lucky it had done no heat damage, however it appears to have been installed the wrong way around with the writing and crank rotation facing inwards rather than as noted on here.
Maybe a good thing it did leak so it seems or the fact it was installed incorrectly.
Now when correcting the rods an pistons I purchased a full rebuild Felpro gasket set which included a rear main rope set among everything else.
In-fact there are what appears to be two sets of rope seals two very long ones and two shorter plus of course the rear side main cap seals.
But after reading this thread where it appears a rope seal maybe more available than a Payen lip seal I read that the later Felpro one is regarded as garbage ?
How do I best proceed from here Guys ???
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Re: rear main seal info

Post by cjv-35 » Mon May 18, 2015 9:59 am

I bought the two piece rubber seal from Midwest Military and my mechanic installed it last week. So for no leak. It is made by Best Gaskets, but I forgot to write the number down which is on the seal. It is a wiper type as on the seal for the diffs and transfer case. :D

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Re: rear main seal info

Post by Sean Collins » Fri May 22, 2015 8:20 am

cjv-35 wrote:I bought the two piece rubber seal from Midwest Military and my mechanic installed it last week. So for no leak. It is made by Best Gaskets ...
Good to see these new seals getting some attention!

It appears to be a clone/knockoff of the old National 5585 lip seal (no longer made), and if made with good quality material, should prove to be the best modern alternative to the old school rope & wiper seals.

Don't have one in-hand yet to examine (some day), but snagged a photo (links to larger):
  • Image

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Re: rear main seal info

Post by artificer » Fri May 22, 2015 9:48 am

That 'lip' seal is not dissimilar to the Payen & should work great on a good running crankshaft surface.
Doing this without being too tight or producing the excessive heat, eventually seizing up.
That was/is the issue regarding the 800093 seals that have been giving some folk grief over the last decade or more.

The benefit of this type seal will show up with a re-built engine not nearly locking up &/or being extremely hard to turn over, after the rear main is installed.

I would offset these 10-15* when fitting up so the butt joints are made inside the block & bearing cap plus use assembly lube on the crank journal & lip to prevent seal damage on startup.
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
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Re: rear main seal info

Post by cjv-35 » Fri May 22, 2015 11:52 am

One week and a day and so far no leak. I looked up the number on the Best Gasket site, at the time I received the seal, but the number did not come up. Special production run ? I believe the Dealer in New York sells this seal also. Artificer, I would think you are correct in that the crank seal surface has to be in smooth, good condition or this type seal would probably leak also. Sean , never heard of the National 5585 seal.


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Re: rear main seal info

Post by Sean Collins » Sat May 23, 2015 7:55 am

cjv-35 wrote:.. Sean , never heard of the National 5585 seal.
It was a true lip seal made back in the day, out of production for many years now, so it doesn't get much exposure or comment. It's a better design than the Victor, so don't know why it didn't make it.

The Midwest/Best seal appears to use the same lip style, w/slightly different groove fit molding.
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John Bartons engine rebuild series showed one installed in the main cap (but backwards :-))
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Re: rear main seal info

Post by Ben Dover » Sat May 23, 2015 8:01 am

Has anyone attempted to index the Jeep rear main seal?
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Re: rear main seal info

Post by artificer » Sat May 23, 2015 2:35 pm

YES.
I practice what I preach & actually still get my hands dirty.
The following link says it all so why waste time re-hashing again & again.

viewtopic.php?f=105&t=180588&hilit=pete+silfven+index

That story is ancient history, but always gets raised, & I don't know why the protagonist has never tried, but keeps asking the exact same leading question of others.
Indexing is common sense & can easily be done with any 2 piece solid seal, but not the woven rope type.
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Re: rear main seal info

Post by Ben Dover » Sat May 23, 2015 4:24 pm

Has any G-503 member indexed a molded rear main seal in their Jeep engine as John has suggested? it has been 4 years since the method has been suggested and no one appears to have done it, or at least mentioned that they have tried it.
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Re: rear main seal info

Post by bootsperformance » Mon Nov 09, 2015 7:47 am

Ok guys add me to the list of guys looking for the Payen seal. Tried contacting them with no response so far. My jeep has 700 miles on it now since I put it together. I had no leaks for the first 300 miles then a small leak developed and this past weekend I took her to a veterans display and now she's dripping quite a lot leaving a puddle. I'm going to pull the engine as soon as I find a good lip seal. I'd rather not go with the rope seal again. Anyone have another source for these seals?
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Re: rear main seal info

Post by artificer » Mon Nov 09, 2015 10:20 am

Are you sure it is engine oil?
Smell & rub between thumb & index finger.

The edge or lip type neoprene seal you are looking for is very good, but it will not fix a rear main leak that a rope style won't if fitted properly.

The reasons the rear main seal leaks are:
1. Worn main bearings [this is the primary cause on a tired engine that is leaking & fitting a new seal of any type won't fix this leak].
2. Grooved/rusted/pitted crank journal sealing surface [the rubber lip or edge type seal performs worse in this scenario].
3. Improperly fitted seal.
Here is how to do it right:
http://www.youtube.com/watch?v=kSQWlnvAIbI

With a fully machined/overhauled engine one must be looking @ 3 & perhaps @ a stretch 2.
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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Re: rear main seal info

Post by bootsperformance » Mon Nov 09, 2015 5:52 pm

good video. Thanks
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Re: rear main seal info

Post by bootsperformance » Wed Dec 02, 2015 5:42 am

I got my seals from Joop yesterday. Compared to the others a bought they look to be what I want. I have a few events to attend in the coming weeks so while I'm on my Christmas break I'll swap the rear seal out and give you guys an update. :D
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Re: rear main seal info

Post by Chevy427z » Mon Dec 28, 2015 6:16 pm

Hi folks.

I have finally gotten around to working on my rear main seal. Getting it out was a piece of cake. Getting it back in has been another story. Both new and old are neoprene, so someone's been in here before.

I have done this job hundreds of time on late 60s GM vehicles and never had a lick of trouble. The new neoprene seal slipped right back into where the old one came out. I had nothing but absolute grief trying to get this new seal back in using that method and completely destroyed it in doing so.

I have been scouring every post in here with the search words "rear main seal" to learn about dropping the crank slightly to ease the installation and come up blank. All I see are posts referencing "If you have difficulties, the engine must be pulled and the crank must come out. My question is, is it possible to drop the crank just 1/16" (even 1/32" would help) to ease the installation without further engine disassembly? My concern is tension on the seal in the timing case cover and/or pressure from the clutch end keeping anything from moving downward. Obviously, I have the main caps loosened.

Additionally, I have a question about "indexing". In my searching, I've yet to find the definition. All I read about is people arguing over it. If it's what I think it is, it has to do with cocking the seals slightly so their flat portions aren't even with the block/bearing cap surfaces? If that's the case, I've also done that hundreds of times while working on the aforementioned GM products, with great success.

To make the night a complete failure, just as I was attempting my final installation of the night, I got stung on the elbow by a freaking hornet. Dec 28. A freaking hornet. Aside from the searing pain at the point of impact, my hand started to tingle so I called it a night.

Any advice y'all can offer will be greatly appreciated! many thanks!

Mark
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Re: rear main seal info

Post by artificer » Mon Dec 28, 2015 7:13 pm

Of course most mechanics that have been around the block know of & practice offsetting neoprene rear main type seals. Offsetting or indexing about 7* is what I practice & it is a piece of cake.

Someone who has led a very cloistered existence & has never tried or been shown how to, wants others to do it or experiment for him.

I suggest before going further it would be advisable to post a picture of [or link to] the type of seal you are attempting to use.
That will be a requirement to answer appropriately.
John GIBBINS Member Institute of Automotive Mechanical Engineers [Ret], ASE Master Medium/Heavy Truck & Auto Technician USA -2002 Licensed Motor Mech NSW MVIC 49593 Current 2015
TO DIAGNOSE, TROUBLESHOOT OR FAULT FIND ANY AUTO SYSTEM....
Understand how system parts interact with one another. GOOD parts can then be established & the NOT GOOD problem/s part/s isolated for repair or replacement.

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