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Rear Main Seal Question

Mikey

NAXJA Forum User
Location
Sacramento, Ca
Whats up guys!!!

I am replacing the rear main seal (I am actually doing more, but this is a "Since I am there" kind of thing) in my 97 XJ 4.0L (180,000 miles). I pulled the oil pan off and it was surprisingly clean. I was expecting a lot of sludge build up on the bottom.

Anyway, I was looking at the crank and noticed that there is a piece that bolts to all of the caps on the underside of the crank. What is it? Do I have to remove all of the caps? Is this something standard on the motor? I was just hoping to get in there, pull the rear cap off, and replace the seal. Now what?

Here is a pic of that piece:

97XJCrank1.jpg
 
Hmm, I've done rear mains on 3 4.0Ls....and I definitely do not remember seeing a piece like that under there.

It looks like you must have to take the whole thing off to do the rear main! How thick is the metal? Could you just get the rear main cap off and bend it away?? If it's for strength, then I would guess no.

If you have to take the whole freakin thing off, you might as well just replace all of the crank journals while you've got every freakin cap off!! You'll have to retorque them anyways...
 
Mikey said:
Can I remove it without removing all of the caps?
yes the caps are double nutted just make sure you torqu them on good and tight when you replace it.

the brace is only on newer 4.0's

might wana replace the oil pump while your in there.......It's standard practice for me if I pull the pan I replace anything I normally wont have access to
 
IIRC it's a windage plate. It's designed to keep the oil in the pan from coming up at hitting the crank while it's spinning. Some people put these in when they are trying to make a performance gain.
 
The brace is common on all '96 and later 4.0L engines. It isn't a windage plate, but is a heavy, thick piece designed to add even more rigidity to the block. Search 'NVH' in posts by me in the last two years and there's more explanation, but they are designed to reduce Noise, Vibration and (Harshness?)

Jim www.yuccaman.com
 
...and yes, the whole plate has to come off. When it does, you remove the bearing caps as usual.

Jim
 
Yucca-Man said:
The brace is common on all '96 and later 4.0L engines. It isn't a windage plate, but is a heavy, thick piece designed to add even more rigidity to the block. Search 'NVH' in posts by me in the last two years and there's more explanation, but they are designed to reduce Noise, Vibration and (Harshness?)

Jim www.yuccaman.com

I guess that makes sense, since the newest 4.0L that I've ripped apart was a '94.
 
Thanks. I will pull it off and get started soon. Just struck me wierd. I pulled the pan off and expected to get started by pulling off the rear cap and then saw that piece:doh: ...WTF??? LOL...

Do I make sure that the nuts on both sides of that piece are torqued down to the cap torque specification or just the ones that have direct contact with the cap?
 
I don't recall the torque specs, but I believe it was less than the bearing caps...if I could find my FSM that's one more thing I should look up.
 
IIRC it is called a girdle....something you young whippersnappers wouldn't know about.
 
old_man said:
IIRC it is called a girdle....something you young whippersnappers wouldn't know about.

I played football, girdles hold your tailbone pad and hip pads in place. In the summer time, not 100% necessary though.
 
I had already looked through my FSM, but nothing is mentioned about that piece. Common sense says to have it all torqued to spec (80 ft lbs), but I just wanted to know if anyone had done different or had encountered this before.
 
I have combed through my FSM and only found something in the torque specifications that mentions a "Main Bearing Brace". First it states the "Main Bearing Cap Bolts" should be torqued to 80 ft lbs. Below that, it lists the "Main Bearing Brace Nuts" to be torqued to 35 ft lbs. That is the only part of my manual that mentions this brace. Can I guess that this is the correct one since it list the caps as having bolts and then the brace as having nuts?

hasta
 
old_man said:
IIRC it is called a girdle....something you young whippersnappers wouldn't know about.

Or a "stiffener"....Again something the young whippersnappers wouldn't know about.
 
I think I may fall into the young whippersnapper category!:rattle:

I am just a whippersnapper in love with my XJ...don't tell my wife:shhh: .
 
Mikey said:
I have combed through my FSM and only found something in the torque specifications that mentions a "Main Bearing Brace". First it states the "Main Bearing Cap Bolts" should be torqued to 80 ft lbs. Below that, it lists the "Main Bearing Brace Nuts" to be torqued to 35 ft lbs. That is the only part of my manual that mentions this brace. Can I guess that this is the correct one since it list the caps as having bolts and then the brace as having nuts?

hasta

That sounds about right, and I think it's what I listed for the brace stud nuts as well...
 
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