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Rear Main Seal - Pull Engine or Tranny? 
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Post Rear Main Seal - Pull Engine or Tranny?
I mentioned this in another post, but I thought I would throw it out as a new topic. My rear main seal is leaking like a bucket, so I'm going to have to replace it soon. What do you guys think is easier/faster, pulling the engine or transmission?

My thought is that the enginer is easier because you're working above the car, but it's more time consuming because you have to take a lot more stuff apart to get it out. The tranny might be faster, but more cumbersome because you're working under the car with the big tranny balancing act.

THoughts?


Thu Oct 19, 2006 2:00 pm
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Hate to be the bearer of bad news but I think you'll have to pull the engine. The crankshaft has to come out. Sometimes you can sneak the seal out by removing the oil pan, then remove the rear main cap, loosen all the forward main caps to lower the crankshaft, slide the old seal out and the new seal in. There used to be "Chinese handcuffs" and corkscrew tools to remove the old seal but it's pretty far up in the block so I'm not sure how easy it would be to access. It's a rope type of seal and may have to be cut to fit too. Hope the info helps.

Lou


Thu Oct 19, 2006 10:33 pm
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Post rear main seal
Lue is right it is a rope seal I have tryed to pull or push one out did not work had to take the engin out I have heard you can push a wire behind the upper seal loosen all the mains so the wire will go in I have not tryed this I think would try do pushing a wire be hind th seal in the cap first it would be easer then under a veh. ED


Sat Oct 21, 2006 11:22 pm
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If you can get your vehicle up high enough to work underneath you can change the seal without removing the engine or trans. Drop the pan, pull the flywheel bottom cover if a stick shift. Remove the rear main cap. Inspect the bottom rear main bearing. If it is worn very much you will have to decide whether to live with it or replace the bearing. Seals do not seal well on a shaft which is slopping around in the bearing that locates it. Loosen the four center main cap bolts about one turn to allow the crank to drop down ten to twenty thousandths. Now is the fun part. If you are lucky, it will have a rubber seal and jou can just push it out with a brass driver like a one eighth gas welding rod. If it is a rope seal you could still be lucky. If it is leaking real bad it could have kind of rotted out or decomposed. I think that some of the newer additives eat them up. If it is still hard use a set of needle nose pliers and gently pull down on it. If it doesn't come down try rotating the crank while pulling. If no luck try loosening the main cap bolts a little more. Do not!!!! do anything to scar up the seal surface on the crank!!! A thin brass stiff wire can be flattened on the end and pushed up on both sides of the groove in the block to free up the seal. One quarter circle on each side of the crank. Try to take the seal out in one piece rather than chewing it up. If you can get it, Use a rubber seal for a replacement. In any case clean the groove in the main cap and block carefully. Some main caps have a small pointed stud in the Main cap groove to prevent rotation of the rope seal. Leave it if you use a rope seal, remove it if you use a rubber seal. Try your utmost to get a rubber seal for a replacement . They probably still make them. They did for 292 v 8s and the six may use the same seal. They are much easier to install and seal better, especially in engines with main bearing clearance on the loose side. Remember that if the bearings are real worn, that replacing them with new bearings will position the crank a few thousandths higher in the engine which in a worn engine will force the rings up against the ledge worn by the rings in the top of the cylinder. This can break the land between the top and second rings. Better not to replace the bearings. I recommend using brass wires for tools because they come in a variety of sizes and are softer than the crank or block and will not cause scratches. If using a rope seal and you can get it in you will have to install and remove the rear main several times to make sure that some of the seal material has not squashed out to between the main cap and block which will "censored" the cap and cause looser rear main bearing . Good luck!!!! Please post your results.


Sun Oct 22, 2006 12:42 am
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Hard to believe this was all the way back in October when I posted this! I've been tied up on other projects and been driving the Fairlane with a case of oil in the trunk. The leak is REALLY bad now, so it's time to tackle it this weekend.

I am going to try flatford6's method first. Might as well because it would be nice not to have to pull the engine or tranny, even if it takes longer. It was a bear getting them mated up last time.

If anyone has any last minute advise or pointers, post them here soon because I'm goin' in!


Tue Feb 27, 2007 11:49 pm
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Quick follow-up.

The seal that I bought several months ago is rubber, so that should hopefully make things a little easier. The directions in the post above are great. If you want to elaborate with even more details and a "rear seal replacement for dummies" approach, feel free! BTW - mine is an automatic tranny. This is somewhat uncharted territory for me, but I really want to do this one myself.

I haven't looked at the new seal since I bought it back in October. I am assuming it's just a rubber donut?

Also, since I am dropping that pan, should I go ahead and replace the oil pump and pickup or just not worry about that?

I am taking the day off work Friday to get a head start on this for the weekend. The transmission pan gasket is leaking, too, so I'm going to replace that while I'm under the car, too.


Wed Feb 28, 2007 10:57 am
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Got it done today. Not quite as bad as I expected. I had to remove the steering stabilizer to get the oil pan out, but that was just 8 bolts. There isn't much room to get the oil pan out! It barely fits out and that was after having to unbolt the oil pump pickup tube and let it drop in the pan to buy a few more inches.

The existing rear main was a 2-piece rubber seal. I was having a hard time getting the top one out. I tried a welding rod and a punch to get it started and it wasn't moving much. I then had the idea to take the old lower seal and flatten it out with a hammer. Since it's the exact same profile as the upper half and the wire inside is the same, it mated with up with the top seal. I tapped it a couple of times with a hammer and it started working its way around. I cleaned everything up real good, installed the new seals and put everything back together. The oil pan gasket I bought was a 1-piece rubber one, so it was relatively easy to get back on, too.

I have never looking inside the bottom end of this engine before. When my original 223 blew, I found this one locally and was told it was in good shape so I just dropped it in. There was a tiny bit of sludge in the bottom of the oil pan, no metal shavings at all and everything looked surprisingly clean. The rear main that I took off and the oil pan gasket was rubber, so some kind of work was done to this thing at some point in the past...but it was most likely a while ago.

I am going to let it sit overnight and have the adhesive on the oil pan gasket cure before I pour in the oil and fire it up. All said, I had about 5 hours in the project. Not too bad. Now, I just have to cross my fingers and hope nothing leaks tomorrow!

I will post an update after I take her on a test drive tomorrow.


Fri Mar 02, 2007 8:06 pm
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Test drove it today. It's still leaking. Not quite as bad as before, but it's definitely dropping a fair amount of oil. I guess I have bigger issues than the rear main. Time for a rebuild...

I am going to try heavier weight oil to buy some more time, but it looks like I now have my summer project lined up for me!


Sat Mar 03, 2007 4:22 pm
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Is it still leaking out the rear main? You could try the technique WSA espoused, where the seal ends are offset by about 1/32" from the block/cap interface, and they're given the lightest dab of Lexus "FIPG" sealant.

I'd also wonder about trying to get a good dose of moly grease into the seal groove before bolting up, and also dry cranking a few times to spread the lube about before your motor fired.

Although it's backtracking to some extent, got to be better than a rebuild - if that's not due yet.

Cheers, Adam.


Sat Mar 03, 2007 5:28 pm
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It has to be the reat main. When I look underneath, it's dripping (almost pouring) out between the engine and tranny.

Where is in information about the "WSA" method? So, you rotate the seals so that they don't meet at the block/cap connection? Interesting. Any more info on that would be appreaciated.

The good news is that if I have to go back in there, it probably won't take as long. I know exactly how to get the pan down and all that other good stuff that slowed me down last time.

Thanks,
Dave


Sun Mar 04, 2007 12:37 pm
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I did a search and found some posts in other engine threads that said the flexplate to crank bolts were part of the cause of the leak - they need to be sealed. Is this the same on the 223?

Looking at other posts on rear mains, it seems like several folks had to try more than once to stop the leak. Should I try again???


Sun Mar 04, 2007 5:14 pm
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If your crank flange bolts are through drilled, then yes - even Ford used a Permatex type sealant on them when new.

WSA is one of our members - he used to be a Lexus tech and reckons their sealant is one of the best on the market. The offsetting of your seal faces is something Ford got into with the later engines that had 2-piece seals. It sort of makes sense in that any displacement of the seal ends due to clamp pressure, happens within the machined groove - rather than at the metal interface.

With the block in the ar, and your crank still fitted - it's always going to be fun getting the seal in a dry groove, lube on the seal running face and sealant on the butted ends! I think that's why many people have several cracks at it... A hoist would be nice, eh?


Sun Mar 04, 2007 5:48 pm
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addo wrote:
With the block in the ar, and your crank still fitted - it's always going to be fun getting the seal in a dry groove, lube on the seal running face and sealant on the butted ends! I think that's why many people have several cracks at it... A hoist would be nice, eh?


Very true! I bought a hoist today, so round two may involve pulling either the engine or the tranny. My initial thought is that I have some bearing/crank wear. I wonder if replacing the main bearings and installign a new rear main seal again would get me by for a bit longer.

Funny thing is, I bought a 302 and an AOD a few months ago and have been working on it with the intent od swapping it into this car. Working on the 223 again has me rethinking that. As quirky as some of the parts on this engine are, I still want to keep it original. I may sell the 302 and AOD to help fund a rebuild of my inline 6.


Sun Mar 04, 2007 9:00 pm
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I don't think that the leak is through the flywheel bolts, They do not go into the engine oil side of the flange like the bolts in the later small six, large six and small block v8. The flange on the 223 six and y block v8 are to the outside of the seal. The instructions for two piece seals usually state to offset the parting line of the seal from the parting line of the block to the main cap. I usually leave about 1/4 inch offset. The other question is did you replace the trapezoidal side seals on the rear cap. They need to be pressed in all the way up in your case. The last 1/4 inch is usually tighter than the first part. Some kits include side seals made of a paper material that gradually expands as it absorbs oil. It will not seal immediatly. If so, give it time, and it will seal. Did you have to cut off any of the side seals. Usually only a very little bit has to be trimmed. If you had to cut off more, the side seals may have not been pressed up to good contact with the block. Some kits have rubber seals that require a wire to be pressed into a groove in the seal after the rubber part has been installed. I had one groove seal (on a 427 Ford) where the groove was machined wrongly and was too wide for any standard side seal to work. I had to shim it with a razer cut piece of an extra seal. That was the paper expando type. It worked though. Good luck and please post your results.


Mon Mar 05, 2007 1:43 am
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I wasn't able to offset the seals (of course) because I replaced them with the engine and trans still in place. I also reaplced the trapezoidal seals. The Fel-Pro rear main seal kit came with the side seals and the litle metal pins. I didn't need to trim them because they were exactly the right length. IT actually came with two sizes of side seals - because t said that seal is used on multiple applications.

This time, I am goint to take a closer look at the crank to make sure it's not grooved where it meets the seal. I'll also look at the rear main bearing. Question - if the rear main bearing does need to be replaced, can I just replace the rear, or should I replace all of them?

I also ordered a BOL seal this time instead of a Fel-Pro just in case it's a slightly different shape.

Thanks again to everyone for the input and advise.


Wed Mar 07, 2007 10:52 pm
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UPDATE:

Round two began yesterday and I installed hte BOL rear main seal. I installed it per the advise in this, and a couple of other, threads and it went smoothly. The only thing I couldn't do is offset the halves of the seal because I did it with the engine and tranny still installed. The difference this time was that I put a small bead of Permatex #3 (I didn't have time to get the Toyota sealer) on the mating surfaces.

GOOD NEWS:
It worked like a champ. No drips from the rear main after about a 75 mile test drive.

BAD NEWS:
I am getting a ridiculious amount of blow-by so it looks like a rebuild is in order anyway. Bummer. I'm sure it was blowing my before, but the rear main leak was so bad, it all looked like one big leak.

Back to the drawing board...and bank!


Mon Mar 19, 2007 11:03 am
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What about trying the racecar technique of drawing a vacuum from the crankcase, with your exhaust? It might help for a while.

Glad the seal worked, though.


Mon Mar 19, 2007 5:38 pm
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