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Replacing RB's rear main

beanhead

beanhead

May I Land My Kinky Machine
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Ok..for starters, yup I've read the sticky and just about every other thread on just about every other site. I'm going to replace the seal myself. Engine is out but I don't want to completely remove the crankshaft. #5 cap is off for access. The builder offered to redo it but I said I just assume do it to save the hassle of transporting it, waiting for the shop etc..knowing full well any future failure is on me...(he, in return, gave me two new superformance pan gaskets, new viton seal, a case of Gibbs break-in oil and a couple of good filters..I was good with that.) So, just to run this by those more 'in the know', I'll put a very light smear of rtv on the block and retainer seal surfaces, (not on the crank/seal surface obviously). On the Mancini retainer with the two small side seal slots, I plan to just use rtv...let the seal locate the retainer after getting things lined up. The block-half seal looks to have good contact on both sides of the crankshaft but I think it's still a good idea to offset the parting lines a bit as described by 340challenger and others? And a very small dab of that red permatex stuff on the seal ends, yeah? Your advice is appreciated!
 
Sounds about right and just read that link Justin supplied to refresh my brain.

As for "advise appreciated".... I'd be letting the guy that f'd it up the first time do it again!
 
dadsbee said:
Sounds about right and just read that link Justin supplied to refresh my brain.

As for "advise appreciated".... I'd be letting the guy that f'd it up the first time do it again!
Click to expand...
^^^^^
In bold nailed it!
 
moparnation74 said:
As you stated use a light coat of RTV sealant......I too stagger the ends and use red loctite sealer.

This is a very good article and what I follow...
http://www.hughesengines.com/Upload...in_Seal_Installation_InstructionsJune2006.pdf

Once complete let it "set" for 24 hrs before messing with the engine again....
Click to expand...
Thanks! It will have more than 24 hrs to cure...I gotta do some more post-flame cleanup and get some wiring replaced.
khryslerkid said:
Read the sticky again, download the pdf in post #10 and follow it to the letter.

https://www.forbbodiesonly.com/mopa...-thread-on-rear-main-seal-replacement.127618/
Click to expand...
Did that the other night, it's a good guide!
 
beanhead said:
Did that the other night, it's a good guide!
Click to expand...

One more thing I didn't do and wish I did, fill in the seal retainer bolt holes level with sealer when putting the pan gasket and pan on. Some gaskets don't totally cover the holes and it leaves a void. That can allow oil to seep past the gasket.

I learned this from one of our great engine builders on here after the fact. I'll only get a small leak after jacking up the front for a period of time, then letting it back down. Wipe it off and it will stay dry until I jack it up again. Weirdest thing I ever saw until it was explained what was taking place.

20190601_001754.jpg
 
khryslerkid said:
One more thing I didn't do and wish I did, fill in the seal retainer bolt holes level with sealer when putting the pan gasket and pan on. Some gaskets don't totally cover the holes and it leaves a void. That can allow oil to seep past the gasket.

I learned this from one of our great engine builders on here after the fact. I'll only get a small leak after jacking up the front for a period of time, then letting it back down. Wipe it off and it will stay dry until I jack it up again. Weirdest thing I ever saw until it was explained what was taking place.

View attachment 775422
Click to expand...
Roger that...I did that before as well. That always seemed like another possible trouble spot..
 
The Mancini billet rear seal is a nice piece. However, the two rubber side seals tend to slip when being installed. I found if you use a drop or two of super glue on the ends it keeps the rubber "o" ring seals in place. Stick the seals in the two holes with a drop of super glue. Let it set up. Use a little rtv, and wrap the seals around the billet and slide it into place.
 
just went through this two years ago after driving on it a season and totally soaking the under side of my 67 GTX I finally decided to have at it on my back under the car !!pulled tranny...
From the research I've done
The rear main seal retainer part of the block is not machined at the time it is machined for the mains from what I've read, and a lot of the blocks were machined off center of the crank centerline. this is not always the case.

I've built and have had built maybe a dozen 440 in my lifetime and this was my first leaker. it being a stroker there has been a lot of speculation about the aggressive knurl on the Eagle stroker cranks that the oil was getting under the seal.hopefully you just have a bad seal.
my fix
1, clean the **** out of everything, then clean again.
2, stock retainer drill out the retainer bolt holes slightly oversize
3, Install felpro PO-5818 rear main seal half in block, off set so 1/4" in 1/4" out at the parting line.
4, use locktite 5699 grey, my engine builder swears by this stuff, a dab on the butting ends and the receiver groove for the seal.
a little on the retainer cap ends were they meets the block.
5, Install retainer, allow the cap to center it's self on the crank, making sure that either side of the retainer is not touching the side walls of the block at this point (if so stop, mill.. the offending side a little for clearance.)
6,now that the cap is centered snug up the retainer bolts
do not use retainer side seal inserts, o-ring pieces, pipe cleaners, wood, .... use locktite 5699 grey and fill the voids and anywhere oil mite try to get by, pan side / outside, retainer to block parting lines ...
(double check the two bosses on the back of the block where the retainer bolts screw into the block I've seen them chipped, (humps broken off)
7,Torque retainer to factory specs
8.let this dry real good I gave it 48 hrs., them installed pan gaskets, windage tray do not over tighten bolts it distort's pan rails, more locktite 5699 all the way around the edge of the pan rail to block, let dry overnight
its' been two years now going on three. leak gone.this worked for me. good luck.
upload_2019-5-31_23-54-16.jpeg
IMG_8377.JPG
 
MOPOWER871 said:
....hopefully you just have a bad seal...
Click to expand...
Thanks! I believe so because it didn't leak before the rebuild, and under close inspection there is good equal seal contact on the block side of the crankshaft. I found that the seal halves were right at the block/retainer line, and there was zero evidence that any sealer was used on the seal ends and that's right where the oil was coming through.. Likely the retainer didn't go down just right and that's all she wrote..
 
MOPOWER871 said:
just went through this two years ago after driving on it a season and totally soaking the under side of my 67 GTX I finally decided to have at it on my back under the car !!pulled tranny...
From the research I've done
The rear main seal retainer part of the block is not machined at the time it is machined for the mains from what I've read, and a lot of the blocks were machined off center of the crank centerline. this is not always the case.

I've built and have had built maybe a dozen 440 in my lifetime and this was my first leaker. it being a stroker there has been a lot of speculation about the aggressive knurl on the Eagle stroker cranks that the oil was getting under the seal.hopefully you just have a bad seal.
my fix
1, clean the **** out of everything, then clean again.
2, stock retainer drill out the retainer bolt holes slightly oversize
3, Install felpro PO-5818 rear main seal half in block, off set so 1/4" in 1/4" out at the parting line.
4, use locktite 5699 grey, my engine builder swears by this stuff, a dab on the butting ends and the receiver groove for the seal.
a little on the retainer cap ends were they meets the block.
5, Install retainer, allow the cap to center it's self on the crank, making sure that either side of the retainer is not touching the side walls of the block at this point (if so stop, mill.. the offending side a little for clearance.)
6,now that the cap is centered snug up the retainer bolts
do not use retainer side seal inserts, o-ring pieces, pipe cleaners, wood, .... use locktite 5699 grey and fill the voids and anywhere oil mite try to get by, pan side / outside, retainer to block parting lines ...
(double check the two bosses on the back of the block where the retainer bolts screw into the block I've seen them chipped, (humps broken off)
7,Torque retainer to factory specs
8.let this dry real good I gave it 48 hrs., them installed pan gaskets, windage tray do not over tighten bolts it distort's pan rails, more locktite 5699 all the way around the edge of the pan rail to block, let dry overnight
its' been two years now going on three. leak gone.this worked for me. good luck.
View attachment 775420 View attachment 775434
Click to expand...

The rear seal GROOVE in many of the Blocks in NOT machined concentric with the Crank Centerline, some are just worse than others but ALL to some degree, in which case if the Seal is just allowed to "SIT" in the factory Block Groove "UN-adjusted" side to side..... one side of the Seal in the worst cases barely contacts the Crank(ANY Crank) = drip... drip... drip....
In our experience only,
On Blocks exhibiting this Groove offset however slight, you have to offset the Seal Halves 1/4" from the parting line, then use the "side to side" clearance in the Factory Seal Retainer itself(all we ever use) once installed but NOT yet tightened.... to then DRAG the offending non-sealing side in the Block over into Crank contact... by applying light pressure with a small screwdriver on the side of the Retainer as you tighten/Torque the Retainer Bolts.
Typically we adjust the Retainer toward the Driver's side of the Block.

We then TEST all BB Mopar Rear Seals for leakage after we assemble the Engine, BEFORE we Dyno them, or Heaven forbid allow a leaky Main to get to a Customer
(NOT GOOD !)

I would suggest anyone else reading this should also TEST their BB Mopar Rear Main Seals BEFORE installing their Engines in the Car, because it's FAR EASIER to re-do the Seal if Required while it's still out ?
42 BB Mopars in the last 5 years.....
NEVER had a leak.....
NEVER used anything but a "stock" Rear Seal....
NEVER used anything but a "stock" Seal Retainer...
 
Last edited:
Challenger340 said:
The rear seal GROOVE in many of the Blocks in NOT machined concentric with the Crank Centerline, some are just worse than others but ALL to some degree, in which case if the Seal is just allowed to "SIT" in the factory Block Groove "UN-adjusted" side to side..... one side of the Seal in the worst cases barely contacts the Crank(ANY Crank) = drip... drip... drip....
In our experience only,
On Blocks exhibiting this Groove offset however slight, you have to offset the Seal Halves 1/4" from the parting line, then use the "side to side" clearance in the Factory Seal Retainer itself(all we ever use) once installed but NOT yet tightened.... to then DRAG the offending non-sealing side in the Block over into Crank contact... by applying light pressure with a small screwdriver on the side of the Retainer as you tighten/Torque the Retainer Bolts.
Typically we adjust the Retainer toward the Driver's side of the Block.

We then TEST all BB Mopar Rear Seals for leakage after we assemble the Engine, BEFORE we Dyno them, or Heaven forbid allow a leaky Main to get to a Customer
(NOT GOOD !)

I would suggest anyone else reading this should also TEST their BB Mopar Rear Main Seals BEFORE installing their Engines in the Car, because it's FAR EASIER to re-do the Seal if Required while it's still out ?
42 BB Mopars in the last 5 years.....
NEVER had a leak.....
NEVER used anything but a "stock" Rear Seal....
NEVER used anything but a "stock" Seal Retainer...
Click to expand...
Having read this advice(many times:)) would you still offset the seal ends even if the seal looks to have good contact on both sides of the crank? Just to help the seal halves line up with each other and the retainer better? Block side of the seal looked pretty good with a visual check, the .002 feeler slid in both sides with very close to the same amount of drag from what I could tell. Surely it's not perfect BUT it' didn't leak on the first build...I do believe this leak was a case of a flawed installation.
 
beanhead said:
Having read this advice(many times:)) would you still offset the seal ends even if the seal looks to have good contact on both sides of the crank? Just to help the seal halves line up with each other and the retainer better? Block side of the seal looked pretty good with a visual check, the .002 feeler slid in both sides with very close to the same amount of drag from what I could tell. Surely it's not perfect BUT it' didn't leak on the first build...I do believe this leak was a case of a flawed installation.
Click to expand...

YES, ALWAYS offset 1/4" the Seal ends from the parting line, as mentioned to keep the half-ends aligned.

Common sense Tech Tip:
rmp engines BB Mopar HANG Test
When we are assembling a BB Mopar here,
we usually install the Rear Main Seal & Crank ONLY, then install the Oil Pan(No Rods &Pistons), and fill with Oil.
then....
we HANG every Engine up to overnight if necessary, and turning the Crank periodically while it's Hanging to make damn sure it ain't going to leak !

If the Rear Main Seal is going to leak ?
Then it will do so when completely submerged in Oil with the Engine HANGING !
usually you will see it within a few minutes, and FAR BETTER to re-do it at this Stage before the Rods & Pistons are installed, or Heaven Forbid in your case having re-installed it in the Car and have to pull it AGAIN !

Remember here: Oil Pan gaskets are CHEAP ! HANG the dam Engine and CHECK the Rear Seal is go to go BEFORE re-installing OK ? might save yourself a Ton of aggravation.
 
Challenger340 said:
YES, ALWAYS offset 1/4" the Seal ends from the parting line, as mentioned to keep the half-ends aligned.

Common sense Tech Tip:
rmp engines BB Mopar HANG Test
When we are assembling a BB Mopar here,
we usually install the Rear Main Seal & Crank ONLY, then install the Oil Pan(No Rods &Pistons), and fill with Oil.
then....
we HANG every Engine up to overnight if necessary, and turning the Crank periodically while it's Hanging to make damn sure it ain't going to leak !

If the Rear Main Seal is going to leak ?
Then it will do so when completely submerged in Oil with the Engine HANGING !
usually you will see it within a few minutes, and FAR BETTER to re-do it at this Stage before the Rods & Pistons are installed, or Heaven Forbid in your case having re-installed it in the Car and have to pull it AGAIN !

Remember here: Oil Pan gaskets are CHEAP ! HANG the dam Engine and CHECK the Rear Seal is go to go BEFORE re-installing OK ? might save yourself a Ton of aggravation.
Click to expand...
Hopefully you put a drain pan underneath! A little oil goes a long way on the floor!
 
Challenger340 said:
YES, ALWAYS offset 1/4" the Seal ends from the parting line, as mentioned to keep the half-ends aligned.

Common sense Tech Tip:
rmp engines BB Mopar HANG Test
When we are assembling a BB Mopar here,
we usually install the Rear Main Seal & Crank ONLY, then install the Oil Pan(No Rods &Pistons), and fill with Oil.
then....
we HANG every Engine up to overnight if necessary, and turning the Crank periodically while it's Hanging to make damn sure it ain't going to leak !

If the Rear Main Seal is going to leak ?
Then it will do so when completely submerged in Oil with the Engine HANGING !
usually you will see it within a few minutes, and FAR BETTER to re-do it at this Stage before the Rods & Pistons are installed, or Heaven Forbid in your case having re-installed it in the Car and have to pull it AGAIN !

Remember here: Oil Pan gaskets are CHEAP ! HANG the dam Engine and CHECK the Rear Seal is go to go BEFORE re-installing OK ? might save yourself a Ton of aggravation.
Click to expand...
OK I will offset the ends thank you! And yessir, hanging the block nose up is how I confirmed it was the seal that was leaking...took about 90 seconds to run out once the oil was sitting on it. Thanks again!
 
Hemirunner said:
Hopefully you put a drain pan underneath! A little oil goes a long way on the floor!
Click to expand...
Yeah, right? Especially this gooey, slimy break-in oil...it's like syrup with a layer of bacon grease!
 
Hemirunner said:
Not the rear main but a mess none the less!
View attachment 776317
Click to expand...
Yikes. I used to complain how on-line places sometimes send things in such ridiculously oversize boxes; not anymore..I flatten them and use them for drip pans, to lay on, whatever. Hey at least that wasn't ATF...that crap will run all the way to the street if you let it!
 
I have a buddy that hates the feel of ATF. I once asked him..."What would be worse...Being neck deep in ATF for an hour or being boned in the *** by 5 men?"
His strange response:
"Can I kill the men afterwards?"
Uhhh, what ?
 
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