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Discussion Starter #1
I am getting ready to change my rear main seal(motor pulled, yay). I bought a new one before realizing I already had one. The thing is that it's 16 years old but has been sealed in the bag the whole time. I pulled it out and the rubber feels as soft as the new seal I bought. Would you use it or just go with the new one? Also the instructions for the old seal say to soak it in motor oil before installing, I thought I just needed to smear some grease on it.
 

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The seal might feel soft, but it's still not as pliable as a new seal. Even sealed in a bag rubber does degrade. For the cost of a new seal, why mess with the old one?
 

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The old seal is probably fine, but considering the small price, I would use the new one. Follow the install directions. Do it right the first time. Take your time.
 

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Don't do this on a rear main seal. Use a fresh one.
You really don't want to do this job again or frequently.
 

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Discussion Starter #5
Ok, will toss the old one. Thanks.
 

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I'm well aware of the degrading rubber discussions. For many years tires have been date coded/labeled etc.
Unless seals, parts, assemblies etc are labeled with born on or expiration date how do you know the "new" bought seal or whatever isn't older than the one in hand?

Just askin!
 

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By the way seals, O rings etc. don't use an EPT compound similar to tires. Also over the years tires have used many rubber like compounds nothing like true rubber.

If you browse an O ring cat you'll notice that there are several EPT available for your selected O ring seal, don't recall any listing life expectancy.
 

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EPT??? :shrug:

 

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I am getting ready to change my rear main seal(motor pulled, yay). I bought a new one before realizing I already had one. The thing is that it's 16 years old but has been sealed in the bag the whole time. I pulled it out and the rubber feels as soft as the new seal I bought. Would you use it or just go with the new one? Also the instructions for the old seal say to soak it in motor oil before installing, I thought I just needed to smear some grease on it.
syco,
I agree with others that have said to get a new seal but I am just curious - is this a 289 or early 302 with the two piece seal or a later 302/5.0L with the one piece seal?

Paul
 

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EPT??? :shrug:


When in doubt dismiss it with a funny! A synthetic rubber. Tire rubber is harmed by oils, brake fluid not lkely candidate for seals. Ethylene Propelene Terpolymer.
 

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Discussion Starter #12
syco,
I agree with others that have said to get a new seal but I am just curious - is this a 289 or early 302 with the two piece seal or a later 302/5.0L with the one piece seal?

Paul
Sorry, I never got a notification that anyone else had replied on this post.

It's a 1969 351W with the 2 piece seal. I guess it used to be a rope seal motor as I saw the pin on the main cap had been ground off. I installed the newer seal, and it went way to easily which is a sure sign for me that it will leak.
 

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Sorry, I never got a notification that anyone else had replied on this post.

It's a 1969 351W with the 2 piece seal. I guess it used to be a rope seal motor as I saw the pin on the main cap had been ground off. I installed the newer seal, and it went way to easily which is a sure sign for me that it will leak.
Fingers crossed.


Z
 
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