Author Topic: rear main seal  (Read 1099 times)

Offline 72cudaguy

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rear main seal
« on: March 15, 2010 - 07:31:35 PM »
can a leaky rear main seal be fixed with out taking the engine out of the car?




Offline Glennster

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Re: rear main seal
« Reply #1 on: March 15, 2010 - 08:50:57 PM »
I've never done it, but I was told it could be done on a small block. I think there's a special tool that makes it a little easier. I looks like a difficult job, but it beats the heck out of pulling the engine.
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Offline quagmire

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Re: rear main seal
« Reply #2 on: March 15, 2010 - 09:14:35 PM »
If it is a two piece neoprene seal it's relatively easy.  Drop the pan and yank the rear most main cap.  Use a plastic or wooden pick to push the upper half out.  You may need to loosen the other main caps slightly to allow the crank to drop.  The replacement upper half can be pushed around the journal into place.  I've heard that the chinese finger tool helps, but I've probably done a hundred two piece seals on various motors without ever using one.  Oil or grease the seal lips that contact the journal to prevent them from burning up on first start up.  Use a little sealer across the main cap surface and flat part of the seal to prevent oil leaks.  Don't let it get on the sealing lip.

Offline 72rtchallenger

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Re: rear main seal
« Reply #3 on: March 15, 2010 - 09:34:20 PM »
I have done it on a 340,,its not to bad ,,but to get the pan off you have to remove headers in my case or at least take them loose,,and its easier if you remove tie rod ends that go thru the center link and idler arm an swing the center link out of the way,,then after the pan is off you can remove the rear main,,I used a punch to get the upper seal to start moving then it turned right out,,oil the new one good and get it started and it will roll most of the way in,,I did have to tap the end alittle to get it all the way around,,just be careful,if it seams to bind when going thru stop an back it out an oil better,,once in just seal the ends good as stated before and torque the rear cap back on,,I didnt have to loosen any others but that could make it an easier job  :2cents:
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Offline Chryco Psycho

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Re: rear main seal
« Reply #4 on: March 16, 2010 - 01:51:49 AM »
It can be done & I have done it but it is somewhat difficult to do properly , if it is a rope seal it is very difficult to do

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Offline Bullitt-

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Re: rear main seal
« Reply #5 on: March 16, 2010 - 08:58:25 AM »
Make sure it is the rear main...I had 2-mechanics tell me it was & I discovered it was coming from the back of the intake.  :2cents:
Wade  73 Rallye 340..'77 Millennium Falcon...13 R/T Classic   Huntsville, AL
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