Rear main seal
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CF Veteran
Joined: Oct 2011
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From: Summerville, South Carolina
Year: 99
Model: Cherokee
Engine: 4.0
Originally Posted by 90_cherokee
Don't fret...it took me a week to do mine,only because it was my first time doing a rms. The longest part was scraping the gasket off the block and pan. I did get pretty frustrated when the upper portion wouldn't come out. I was using a brass probe used for metal detecting and kept mushrooming the tip. Used a regular punch and it came right out.
My pan was STUCK upon disassembly,and I had to pry and pry. Finally got it to break free. Before I installed the new gasket,I did a test fit of the pan,found out the flanges needed straightening,which I did by bolting the pan back in,and going along the bent flanges with a drift and a hammer. It still leaked when I started it up,so I took a short piece of steel,drilled holes in it in the bolt pattern of the oil pan,and bolted it up with the pan bolts.
Be careful when installing the upper portion of the RMS. Use either the shoehorn provided(stick the skinny end in the hole) and lube the seal with soap. Follow the curvature of the crank as you feed the seal in. It can be stubborn going in but just be patient.Do not take the shoehorn out until the seal is all the way in. If you do,you run the risk of gouging the back of the seal against the edge of the hole your feeding the seal into,and it won't be any good,its guaranteed to leak. So maybe buy 2 rear main seals in case you screw up the first one. The seal goes in with the groove towards the engine,make sure you note this or else you'll get to do it all over again.
Do not forget to install the lower portion of the seal in the bearing cap. Put some oil on the bearing before you put the rear main bearing cap back in. Don't forget to install the main bearing cap either. Im willing to bet there have been some that have been so focused on R&R of the upper portion of the seal,that they either forgot to reinstall the lower seal into the bearing cap,or forgot to install the bearing cap all together prior to installing the oil pan.
If you loosen any other main caps,check and recheck them several times. Torque them to 80 ft lbs.
My pan was STUCK upon disassembly,and I had to pry and pry. Finally got it to break free. Before I installed the new gasket,I did a test fit of the pan,found out the flanges needed straightening,which I did by bolting the pan back in,and going along the bent flanges with a drift and a hammer. It still leaked when I started it up,so I took a short piece of steel,drilled holes in it in the bolt pattern of the oil pan,and bolted it up with the pan bolts.
Be careful when installing the upper portion of the RMS. Use either the shoehorn provided(stick the skinny end in the hole) and lube the seal with soap. Follow the curvature of the crank as you feed the seal in. It can be stubborn going in but just be patient.Do not take the shoehorn out until the seal is all the way in. If you do,you run the risk of gouging the back of the seal against the edge of the hole your feeding the seal into,and it won't be any good,its guaranteed to leak. So maybe buy 2 rear main seals in case you screw up the first one. The seal goes in with the groove towards the engine,make sure you note this or else you'll get to do it all over again.
Do not forget to install the lower portion of the seal in the bearing cap. Put some oil on the bearing before you put the rear main bearing cap back in. Don't forget to install the main bearing cap either. Im willing to bet there have been some that have been so focused on R&R of the upper portion of the seal,that they either forgot to reinstall the lower seal into the bearing cap,or forgot to install the bearing cap all together prior to installing the oil pan.
If you loosen any other main caps,check and recheck them several times. Torque them to 80 ft lbs.
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Joined: Jul 2011
Posts: 322
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From: Sierra Vista AZ
Year: 1990
Model: Cherokee
Engine: 4.0
To get the proper torque on the main caps is critical. You'll need to purchase or borrow a click style torque wrench. Auto parts stores sometimes have a free loaner tool program. You pay a deposit,use the tool,when you return the tool you get your money back. Almost like buying and then returning the tool for a refund. If you don't return the tool...you own it,and they keep your money.
If you've never used a torque wrench,ask the counter person at the store how to use it. When tightening the main cap bolts,don't Jerk on the wrench,use smooth steady pressure or else you'll get false readings. Oil pan bolts...tighten them till they are snug and put just a little more into it. Too much and you'll snap the bolt. Use a criss cross pattern when tightening the pan bolts.
If you've never used a torque wrench,ask the counter person at the store how to use it. When tightening the main cap bolts,don't Jerk on the wrench,use smooth steady pressure or else you'll get false readings. Oil pan bolts...tighten them till they are snug and put just a little more into it. Too much and you'll snap the bolt. Use a criss cross pattern when tightening the pan bolts.
Last edited by 90_cherokee; Nov 20, 2011 at 08:08 PM.
Seasoned Member
Joined: Jul 2011
Posts: 322
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From: Sierra Vista AZ
Year: 1990
Model: Cherokee
Engine: 4.0
Originally Posted by zombie jeep101
Wow, thanks for taking the time to write that! It helped a lot! But one question, how do you check how much you torqued down the bolts??
Senior Member
Joined: Oct 2011
Posts: 689
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From: Longview, TX
Year: 1998
Model: Cherokee
Engine: 4.0L
I literally finished getting my new seal in 20 minutes ago and ran into every problem you did. The one thing I can say is, get a medicine syringe and squirt some dish soap in the groove for the upper seal. This was something I saw (and I'm sure you've seen on YouTube). This made the upper half slide right in.
One question, does anyone have a diagram of where each oil pan bolt goes? My neighbor, who is extremely helpful, but a little over zealous, got all of mine out of order when he was handing them to me. So I'm a little stuck on some of them.
One question, does anyone have a diagram of where each oil pan bolt goes? My neighbor, who is extremely helpful, but a little over zealous, got all of mine out of order when he was handing them to me. So I'm a little stuck on some of them.
CF Veteran
Joined: Nov 2010
Posts: 1,275
Likes: 2
From: North Carolina
Year: 1999
Model: Cherokee
Engine: Gas
I don't know if it was said, but to get the upper seal out, have a friend turn the crank with a breaker bar on the harmonic balancer while you tap it in the same direction with a punch.
Thread Starter
CF Veteran
Joined: Oct 2011
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From: Summerville, South Carolina
Year: 99
Model: Cherokee
Engine: 4.0
Originally Posted by HCCAFan
I don't know if it was said, but to get the upper seal out, have a friend turn the crank with a breaker bar on the harmonic balancer while you tap it in the same direction with a punch.
Thread Starter
CF Veteran
Joined: Oct 2011
Posts: 2,613
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From: Summerville, South Carolina
Year: 99
Model: Cherokee
Engine: 4.0
Originally Posted by 98XJ40K
One question, does anyone have a diagram of where each oil pan bolt goes? My neighbor, who is extremely helpful, but a little over zealous, got all of mine out of order when he was handing them to me. So I'm a little stuck on some of them.
CF Veteran
Joined: Nov 2010
Posts: 1,275
Likes: 2
From: North Carolina
Year: 1999
Model: Cherokee
Engine: Gas
Senior Member
Joined: Oct 2009
Posts: 537
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From: NW Florida
Year: 1999
Model: Grand Cherokee
Engine: 4.0
Seasoned Member
Joined: Jul 2011
Posts: 322
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From: Sierra Vista AZ
Year: 1990
Model: Cherokee
Engine: 4.0
Personally I just put the studs in a where the tranny line brackets "should" go. There is only one stud and one bolt with 1/2 head... 3 studs that are 7/16 and the rest are regular bolts with a 7/16 (on mine at least) and other than being in the correct place for the tranny line brackets... I believe the bolts/studs can actually go anywhere in any order.
Senior Member
Joined: Oct 2011
Posts: 689
Likes: 2
From: Longview, TX
Year: 1998
Model: Cherokee
Engine: 4.0L
Originally Posted by 4Doors
Watch part 1 of my video (on the 1st page of this thread) and I mention where the bolts go. 
Looks like I'll be going back to it again at least once.
Thread Starter
CF Veteran
Joined: Oct 2011
Posts: 2,613
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From: Summerville, South Carolina
Year: 99
Model: Cherokee
Engine: 4.0
Does the oil pump Absolutely NEED to be replaced while I'm changing the seal?? Because I really dont want to have to buy a new one right now... =(
Last edited by zombie jeep101; Nov 21, 2011 at 04:20 PM.