The Official Rear Main Seal replacement thread

themechanic

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Please post quality information here on replacing the rear main seal.
 
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themechanic

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silicone side seals instruction sheet.jpg
 

khryslerkid

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That's the instructions on their site. I liked the ones they sent me with the seals. A lot more detailed with measurements and pictures. I'll have to see if I can find them. They should be online somewhere.
 

themechanic

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That's the instructions on their site. I liked the ones they sent me with the seals. A lot more detailed with measurements and pictures. I'll have to see if I can find them. They should be online somewhere.

I bought the one from Mancini Racing.
 

themechanic

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Yes, but they are not very detailed either.


Mancini Rear Main Seal Instructions.jpg
 
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khryslerkid

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Well I looked and couldn't find the instructions that came with the one I bought from 440 Source. Must have thrown them out.

They had pictures, they showed how to measure the distance between the bearing cap and seal cap, showed how much side seal to leave, ect. Maybe I'll contact them in the next day or two and see if they can email them to me. They would make the perfect "sticky".
 

themechanic

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Well I looked and couldn't find the instructions that came with the one I bought from 440 Source. Must have thrown them out.

They had pictures, they showed how to measure the distance between the bearing cap and seal cap, showed how much side seal to leave, ect. Maybe I'll contact them in the next day or two and see if they can email them to me. They would make the perfect "sticky".

Here is the file. You will need Adobe Acrobat Reader or a similar program to view it.
 

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  • Rear_Main_Seal_Installation_InstructionsJune2006.pdf
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Fran Blacker

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A little off topic. A few months ago I saw in a magazine someone came out with a "one piece" seal for BB/Hemi's.
It only had one opening so you could put it on crankshaft it in the block. Be damn if I can find the article or the name of the guy who makes them. Anyone know?
 

khryslerkid

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Here is the file. You will need Adobe Acrobat Reader or a similar program to view it.
Thats the one! Good job Mechanic :thumbsup:

I was waiting to contact 440 source (different time zone) but you saved me the trouble.

What do you think about useing it for a sticky? Someone can copy each page as a jpeg. I tried but I'll have to send it to my computer.
 

khryslerkid

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A little off topic. A few months ago I saw in a magazine someone came out with a "one piece" seal for BB/Hemi's.
It only had one opening so you could put it on crankshaft it in the block. Be damn if I can find the article or the name of the guy who makes them. Anyone know?
I remember seeing one too. Don't know how good a seal it was or if it was available because I ended up going with the 440 Source one.
 

khryslerkid

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Best that I can do with coping pages from the pdf. Actually took screen shots on my phone and resized. My computer wouldn't save any pages as a jpeg. If these aren't sufficient maybe someone with the advanced Adobe Acrobat Reader could help us out.
20170320_162613.png

20170320_162700.png

20170320_162742.png

20170320_162858.png
 

coloradodave

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The above ^^^^^^^instructions (posted by khryslerkid) are from Hughes Engines. I had the Mancini seal retainer and always had a small leak. I bought the Hughes retainer, which is slightly different, installed it per the above instructions, and finally got a leak free motor.
 

Cornpatch MO

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The above ^^^^^^^instructions (posted by khryslerkid) are from Hughes Engines. I had the Mancini seal retainer and always had a small leak. I bought the Hughes retainer, which is slightly different, installed it per the above instructions, and finally got a leak free motor.
I am glad to hear that. After comparisons, I too, ordered the kit from Hughes engines. It is on it's way. First, I down loaded the instructions ( the ones Kryslerkid posted) and they were very thourough with several pictures. I expect some of the other sources are the same kit. ................MO
 

Challenger340

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The 2nd thread over at Dodge Charger . com was mine.

The problem with leaky mains in BB Mopars, more often than not, is the Groove that holds the seal in the Block is machined "offset" to one side from the Crank centerline....
meaning....
the lip on the seal is NOT COMPRESSED on one side..... and drip.... drip.... drip.
Worse on some Blocks than others.
It never mattered from factory as ALL BB Mopars used a rope seal that would expand/absorb oil on the loose side and seal up
but,
nowadays using neoprene seals..... you get the picture !

The way to check:
* with the Engine upside down on an Engine stand
* Install upper seal half in Block flush with the Block/Main Cap Parting line
* Install Crankshaft
* VISUALLY inspect both sides..... to SEE if the seal Lips have equal compression against the Crank on BOTH sides !
usually this inspection will verify what is quite common on many Blocks.... that one side of the lip is compressed against the Crank, and the other is barely touching/sealing.

* The "Fix" is to offest the non-contacting side approx 1/4" above the Main Cap/Block parting line.... and offset the other seal half the same reverse amount in the Seal Retainer
* Gently work/wiggle the Seal Retainer down into place, do up bolts lightly finger tight
* Then using a screwdriver on the NON-Contacting seal side..... gently apply pressure to the Seal Retainer to move the offending seal side over into contact with the Crank as you tighten down the retainer bolts. Unfortunately, this is a by "feel" type thing ? I can't relate a quantitative amount of sideways pressure to apply on the Seal Retainer as you tighten the bolts.... but just a very gentle sideways pressure to drag the lip seal into contact.

I have been dumb-founded over the decades at the plethora of aftermarket wiz-bang CNC Billet shiney-shit seal retainers being marketed.... all professing to "cure" the problem.... when the Seal Retainers themselves NEVER were the PROBLEM in the first place ?

I'm out..... but next time you are assembling the Crank in a BB Mopar have a close look... you'll SEE what I am talking about.
 

wyrmrider

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The 383 mentioned would be the large main RB motor not the B motor
you still need to center the seal retainer as stated above
 
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