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258 Rear Main Seal

7K views 7 replies 2 participants last post by  LEVE 
G
#1 ·
I just recently purchased a 1983 CJ7....and the rear main seal seems to be leaking.

There's a good amount of drippage from between the bell housing and the engine. I read through two different repair manuals, and the 258 I6 seems to have a two piece seal that can be replaced without removing transmission etc.

My questions, (I know that you have to remove the oil pan and the seal flange (or whatever it's called) and then slip out the old seals and in with the new ones...Sounds simple enough..but we all know how that goes.) ;O)
How drawn out is this task? How hard is it really? Any special tools? Do I need to jack up the vehicle? And do you have to be jacking up and down the engine to get the proper alignment for the upper seal to slide in? And lastly, is taking off the oil pan a non-trivial task?

Thanks everybody...Hope to hear from ya!

Gil in New Mexico

 
G
#2 ·
Replacing the main seal is no big deal, if you do it just make sure it is straight and you don't nick it. BUT, before you go thru all that trouble, make triple sure it is not the valve cover gasket leaking and running down. That is probably the source of 90% of 258 oil leaks. Clean it real good, drive it, see where the oil is really coming from. Just my 2 cents from a fellow NM Jeeper!

Brad
ORC Land Use Section Editor
http://www.off-road.com/land
 
G
#3 ·
i agree w/ brad/wwwthreads_images/icons/smile.gif

check your valve cover bolts and see if they are loose. if so, tighten snug . don't know the torque but i go by feel.

car wash underside and wait to see if leak stops.

clean around the valve cover also to keep an eye out there too.

this happened to me and i also thought rear main seal. discovered loose valve cover bolts and there you have it!/wwwthreads_images/icons/smile.gif

doesn't leak a drop.

call us in the am!
 
#4 ·
if it is the rear main seal.. you have to take out the engine cross member.. pull pan off.. pull old seal out.. to get the upper part out you might have to drive it out.. DO NOT use something hard.. use a brass punch.. or aluminum.. you want it softer material than the block.. that way you dont damage the block.. drive it out some.. and get the pliers on it.. and before you put the new one in.. put alittle bit of oil on it.. then push it up and in.. make sure everything else is clean and dry.. and then.. put oil pan back on.. might need new gaskets there.. and in the corners.. put a good glob of gasket sealer.. RTV.. or whatever you call it.. tighten it up.. let it dry over night.. then drive.. should be good.. /wwwthreads_images/icons/wink.gif
took me 2 tries to get mine.. ugh.. just remember that rtv is your friend..

survival is instinct, but living takes guts

http://www.jeepgod.net
 
G
#5 ·
I had to use a motor puller to hold up the pass side of the engine because you need to remove the pass side motor mount to get that 1 bolt and to clear the pan out but my seal was dry as a bone and brittle the front one too

85 CJ7 very rusty
SE Wisconsin
 
G
#6 ·
Thanks guys...I might go ahead and give it a try, that is after I make double sure that the leak is coming from the seal(s).....I already checked up near the valve covers a bit and did not see anything jump out at me, but I'll clean everything up, drive, and make double sure....

RTV = Friend (Got it!!!)

 
G
#7 ·
Thanks guys...I might go ahead and give it a try, that is after I make double sure that the leak is coming from the seal(s).....I already checked up near the valve covers a bit and did not see anything jump out at me, but I'll clean everything up, drive, and make double sure....

RTV = Friend (Got it!!!)

 
#8 ·
If you do decide to replace the seal.... just a tip...

Loosen the crankshaft cap bearing bolts, just a small amount. This lets the crankshaft drop down a little and makes installing the new seal a little easier without having to redo the job. When you're done, just retorque the cap bolts back to specifications to raise the crankshaft back into place

Good Jeepin'

Larry
 
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