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Rear Main Seal DIY Question


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Can someone recommend a good video that details this job? I've seen a few and they all seem to differ slightly on where and how to apply RTV to the seal area. I just want to do it right.

 

And, yes, the back of the valve cover and the oil filter housing are both dry.

 

Thanks

 

 

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4 hours ago, RG67MA said:

Is that diagram from the service manual?

 

on the topic, I just now successfully freed up the upper half using a 3# sledge and maybe 10" of a 3' bar of 1/4" brass I picked up at my local ACE hardware for 10 bucks.  :L:  I whittled the end a bit to fit and drilled a "nail set" cup into the end (that may or may not have helped).  the dang thing started bending after a couple good whacks, but I bent it back straight and 2 more whacks and the seal came free. :D  

 

IMG_20240908_111943_661.jpg

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more tips:

 

-have a spare new RMS on hand.  if you hurt the new upper in any way shape or form, abandon it for a new new one.

-I use a smearing of petroleum jelly to aid in inserting the new one.  other things can be used here too, but the lesson is that lube is important. 

-putting in the new one sucks.  put the new one up against the crank and fiddle it in to get it started.  then ya gotta push the opposite end with one hand while simultaneously pushing the middle of the seal against the crank with the other hand to get the force of your first hand to translate into a force pushing the seal into the hole. 

-wear goggles. 

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It's not a bad idea to loosen the main caps.  That lets the crank drop just a hair and gives you a little more wiggle room.  Be sure to have a good torque wrench and torque them to spec after.  And then double check them.

 

OEM recommends soap as lube but petroleum jelly probably is good too.

 

And yes, have a couple because you may shave some seal off putting it in if you're not careful.  Those machined faces are a little sharp.  Ask me how I know.:brickwall:

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also, also, if you use a reusable rubber oil pan gasket, take great care to make sure the rear most arch is properly located.  it likes to scoot around because it doesn't fit very snug to the engine.

 

be sure to let the sealant cure before testing out your efforts by firing up the engine.

 

oh, and I bought studs for the rearmost bigger bolts so as to help with initial alignment. 

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2 hours ago, fiatslug87 said:

When I purchased the RMS it came with a little plastic “shim” to protect the seal from getting nicked during installation and is then removed.

This was my experience as well. Wasn’t there someone on here that posted some sort of carbon paper trick with rear main seals? Seems like maybe a few years ago?? It was a nifty trick for installation. 

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  • 3 weeks later...

Thanks for all the helpful responses.

 

After work today, I started this project by draining the oil and pulling the starter.

 

I have another question before I drop the oil pan.

 

My MJ has a Rusty's 4" lift and the factory front skid plate. Do I need to pull the front wheels and jack up the MJ by the frame to let the suspension to droop to get the pan out? It looks tight, but possible without that step.

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1 hour ago, robfg67 said:

Thanks for all the helpful responses.

 

After work today, I started this project by draining the oil and pulling the starter.

 

I have another question before I drop the oil pan.

 

My MJ has a Rusty's 4" lift and the factory front skid plate. Do I need to pull the front wheels and jack up the MJ by the frame to let the suspension to droop to get the pan out? It looks tight, but possible without that step.

The more room the better.  The pickup tube makes getting the pan out difficult.

 

Last time I dropped the oil pan was when I was swapping the axle.

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I’ve never changed an RMS with the engine in the vehicle. I’ve always installed everything with the engine out (typically during a rebuild) and never had one leak. I can see how it would be extra tricky trying to do this with the engine still mounted. 

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And full droop it is.

 

Was the oil pan sealant from the factory RTV or a gasket? 

 

Mine has RTV and I cannot for my life get the pan detached. I looked on YouTube and found a guy who recommended the Lisle 50210 Gasket Separator. I ordered it from Amazon, so this project is on hold for a couple days.

 

Anyone used it before?

 

61Kdx6kGIxL._AC_SL1500_.jpg.38d1d3d3309879b121dd82fbe5181c0f.jpg

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I used a small hammer, 5-way and a straight razor scraper to get the old stuff off.  always a fan of new ideas though, so keep us posted on how that works out. :D   make sure you have goggles and ear plugs so the yucky stuff doesn't get into any of your face holes.  :L: 

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5 hours ago, robfg67 said:

And full droop it is.

 

Was the oil pan sealant from the factory RTV or a gasket? 

 

Mine has RTV and I cannot for my life get the pan detached. I looked on YouTube and found a guy who recommended the Lisle 50210 Gasket Separator. I ordered it from Amazon, so this project is on hold for a couple days.

 

Anyone used it before?

 

61Kdx6kGIxL._AC_SL1500_.jpg.38d1d3d3309879b121dd82fbe5181c0f.jpg

Make double sure all the bolts are out and drive a scraper or small screwdriver in between the pan and It will be stubborn if the rtv job is decent.

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What a brutal job it is when the pan is attached with RTV. I'll have this tool on Monday night, so I'll report back after that.

 

There is not a lot of space to swing a hammer, so I'm hoping this tool will be the one.

 

I thought about using a Dremel cutting wheel-a thin one, but I'm too afraid of damaging the bottom of the engine.

 

 

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