rear main seal


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By DualQuad312 - 12 Years Ago
Hello and thanks for the help and input over the yrs.

I've decided to replace the rear main seal on my 312 engine. I, rebuilt the engine about 3yrs. ago. If you had the choice of rear main seal black rubber (neoprene) or the softer orange type (silicone?) which would you use? Both are from best gaskets. In fact the now synthetic rope seal is made by best gaskets. But any way I'm leaning toward the orange silicone seal as I, just ordered one on e-bay....I, hope I'm right :-) The leak I'm fairly certain was because I, used permatext II and it looks as though the hot engine oil dissolved it. This time I'm planning to use RTV. The side seal retainer and the bolts I, used permatex II. It failed

Jeff
By NoShortcuts - 12 Years Ago

I don’t know, Jeff. I had an an acquaintance install three (3) neoprene rear seals in a 312 engine rebuild this summer. On the fourth try, he resorted to using a rope seal with success. OUCH!


Ted Eaton has an excellent step-by-step article on his website about rear main neoprene seal installation.


In looking at Ted’s web site this evening, I did this to locate it.

- Google www.eatonbalancing.com

- On the Eaton web site listing, toggle the heading, ‘Y-Block’

- On the web page that opens, in the column on the left titled,‘Recent Posts’ toggle the heading, ‘Quick Index for Eaton Balancing Articles’

- Scroll down the list of topics to the 19tharticle…

- Toggle the topic, ‘Ford Y-Block Neoprene Rear Main Seal Installation’

- http://www.eatonbalancing.com/blog/2008/09/10/neoprene-rear-seal-installation-for-the-y-and-others/


Hope this helps. Smile
By Ted - 12 Years Ago

The Best Gasket ‘black’ seal for the 312 engines supercedes the ‘orange’ seal. The orange seal has proven to be too soft and simply wears out without many miles on it. The ‘new’ black seal fixes that problem as it’s made from material similar to that which is used for the 272/292 neoprene seals. Unfortunately there’s likely an inventory of the orange seals sitting on vendor shelves which is going to be a problem for awhile as both seals carry the same part number on the boxes. Once you have the orange seal in hand, you might give Best Gasket a call and see if they will swap out the seals for you.
By DualQuad312 - 12 Years Ago
Hi Ted,

Thanks for the reply and to the other Gentleman for his input. I, to have heard that sometimes the rope seals are the way to go... but unfortunately with the engine in the car It's not feasible. I, should of waited another day till u had time to respond...Lol Sometimes impatience gets the best of me! I, do have the black seal and I had ordered it from a reputable dealer. I'll just send the orange one back when it arrives. I'm hoping I'll have better success this time around....I'm pretty sure using the RTV over the Permatex will make a noticeable difference. at least now I, know the orange seal is too soft. funny thing I, thought it would of been a better seal...

Jeff
By DualQuad312 - 11 Years Ago
Hi Ted,

I, wanted to let you know I, received the rear main seal today in the mail. It turns out it's the black type. I, decided to keep it for another 312 I, have. I, guess the orange type is used up or at least taken off the market?
How ever The picture is Still being used for advertising.... But I, think it's less frequently then in past yrs... I, really had to search to find a picture of this "orange style" which isn't available anyway....

Jeff
By Lanny White - 11 Years Ago
I read the previous posts about the best seals to use and wonder if it is possible to do the replacement with the engine in the car? Several attempts, each necessitating engine removal is a ton of work!
By Hoosier Hurricane - 11 Years Ago
Yes, it can be done in the car. Birds and trucks are a lot easier than passenger cars, but all are doable.
By DualQuad312 - 11 Years Ago

Jon, is correct. I, posted a question about what type of neoprene seal to use (orange or black) about a month ago. All though I, haven't driven the car, I've ran it for about an hour or so with no leaks thus far! Knock-on wood..... It wasn't too bad, I, have a'57 ford Ranchero with a 312.....The part that stinks working on your back and of course being upside down! I, had to jack the engine up about an inch to give better clearance when reinstalling the oil pan but other then that it was pretty smooth....If you have any questions, let me know :-)

Jeff