Replacing 87 F150 4.9L rear main seal

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  #1  
Old 10-18-07, 09:48 AM
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Replacing 87 F150 4.9L rear main seal

Can someone tell me how big of a job it is to replace the rear main seal on a 87 Ford F150 4.9L six cylinder. Can I do it without removing the engine. How long should it take to do the job, the reason I ask is I will have to do it in my driveway and don't really want to have it setting there for a long time and the weather is going to get cold soon. Any help or suggestions will be appreciated. It didn't leak when I bought the truck last year but after I changed the oil it has started leaking bad, so the guy I bought it from must have had some "shade tree" magical stuff in it, which I would replace if I knew what it was. Thanks and have a good one. Geo
 
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Old 10-18-07, 10:53 AM
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The magical stuff is easier, but you can get get it done.

There are two types braided fiber and neoprene (with the lip). The braided fiber probably is not in the picture in the year you have. It seems those went out in the seventies.

What you would have to do is take out the motor mount bolts, raise and block the front of the engine. Keep checking while you do this so you don't destroy anything on the top rear of the motor.

Pull the pan and loosen all the main caps about 1/4 inch at the front one and a little more as you go to the rear. The last cap should be the one that holds not only the bearing but the rear seal. Take that one completely off. Your crank should come down enough to take the pressure off the upper half of the seal. Use something made of hard plastic (nothing made of metal you'll scratch the seal surface) to push the upper half around the crank to the point you can remove it completely.

Lube the new half seal, make sure the lip is pointing toward the oil and install it. It's usually a good idea to raise the crank into place just enough to leave room to put the seal in. That helps to guide it into place.

Put the other half in the bearing cap and put it all back together. Torque all the caps down to specs.

If everything works like it should about three hours.

Hope this helps,

Bob
 
  #3  
Old 10-18-07, 06:09 PM
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Check it might be a one piece seal... Look it up before you pull it down. If I get a chance later I'll see if I can find it in the manual.
 
  #4  
Old 10-18-07, 07:05 PM
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Thanks guys, I really appreciate the feed back. When I was younger this would have been fun, now it is just a necessity. I put some Bar's Rear Main Seal Repair in it, which says the leak will stop in 100 miles or 2 days driving, the way this thing is leaking, I doubt it. I drove 25 miles and lost a quart of oil. Oh well guess I got what I paid for. Thanks again, have a good one. Geo
 
  #5  
Old 10-18-07, 07:20 PM
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Geo:

The engine you have does have the one piece seal. Sorry. You could do that one in frame, but the tranny/flywheel would have to come out.

Back to the pour in sealer.

Later,

Bob
 
  #6  
Old 10-19-07, 10:03 AM
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Does anyone have any ideas for a pour in sealer that would stop the leak or at least slow it down some. It would be pretty tough to screw up the engine any more than it already is it has 185,000 on it and has almost no oil pressure which is why I changed the oil and put in 20w50. Thanks and have a good one. Geo
 
  #7  
Old 10-19-07, 11:39 AM
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Not if you are losing a quart every 25
That's huge
Anything you pour in will pour right back out again

Anything that could stop a leak that big (if it existed) would be too thick to lube the engine...it'd block all the pump parts and drain back holes...everything else...pour in is not an option at this point
 
  #8  
Old 10-19-07, 03:33 PM
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I'm afraid with the low oil pressure you're headed toward an overhaul or replacement on that one. You could fix the rear seal, then the rod/main bearings, but with 180,000 it will keep coming at you a little at a time.

Before I put any more money into it, I would think about another engine or a major on that one.

Later,

Bob
 
  #9  
Old 10-19-07, 05:01 PM
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I hate to dump $$$$ into it, I use it very little, 350 miles in the last year, it only gets used if I need to haul something. It's a 4 speed with granny low, at idle it could pull a house down. lol Have a good one. Geo
 
  #10  
Old 10-19-07, 05:31 PM
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Yeah those 4.9 sixes are little torque monsters
 
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