Accessing the Rear Main Seal

6

67-Conv-200

Active member
Hi,

I have a 200ci in my 67 mustang and I am rookie when it comes to motors. I have removed the oil pan and I'm trying to find out how to access the rear main seal. See the following picture.

IMG_5362.jpg


As you can see, I have the oil pan and flywheel cover off. What else do I need to remove so I can get access to the rear main seal? The new seal is 2pc rubber that I should be able to get around the crankshaft. I am expecting the old one to also be a 2pc rubber seal or a rope seal.

The Ford manual documents how to replace the seal with the engine out, I haven't been able to find how to replace it with the engine still in the car.

Thanks
 
Remove the rear bearing cap to access the lower half of the seal. You will need to remove several of the caps and loosen the rest to access the upper seal. I do not remember if there is a pointed pin to keep the upper from sliding out.
 
You're gonna have to get rid of that little "pointed pin" in that rear main cap. It's there for the rope seal and it will destroy the new 2-piece seal. Ask me how I know...

Some times you can knock them out, I think I used a cutoff wheel to grind it down smooth. Maybe someone has a picture they can post.
 
@ aribert
That is what I thought. I removed the 2 main bearing cap bolts, but the cap will not budge. This is what made me think I was doing something wrong. Is there a trick to getting this off?

@ Econoline64
Thanks, I heard about the pin and will keep an eye out for it. I am hoping, but not counting on, that it was already removed during the rebuild of my engine a few previous owners ago.
 
The cap is tough to remove - you need to put the bolts just into the cap and use them to wiggle the cap off. Don't use anything else, don't attempt to apply more force. It'll take some work.

I have done this job exactly once, and my rope seal was *brutalized*. I think it was installed using some sort of sealant or something. Getting it out was an epic struggle and basically required removing the crank. I'm sure it's a worst-case scenario, just be prepared and be sure you really wanna replace it. Once you start, you can't stop. :D
 
As thesameguy said, be certain that you really need to replace the upper half of the rear main seal. Depending on how bad it was leaking and how close you are to an engine rebuild, I would consider just replacing the lower half of the seal. I would consider pressing on the ends of the upper seal portion and cutting the lower half a bit longer for a good interferance at the joint and to put a little bit of extra pressure on the old upper half seal.
 
I wanted to replace both the upper and lower seals. I'd feel like I only did half the job if I hadn't.

The old seal was rope and the upper part wasn't hard to get out. I cut the tip off a nail, then used it as a punch and got one side out then pulled it with pliers. The new rubber seal slid right in. The cap had the spike which I punched out and filled with RTV sealant. I rubbed both parts with oil like I would a new filter and used RTV sealant on the ends of the seal only.

All said and done, yet the car still leaks. It is better, but it is still quite a lot. It looks like it is dripping down the inside of the flywheel cover. Did I miss a seal or is this still the rear main? I may try a rope seal if I go in there again.
 
thesameguy":zkbams7x said:
Did you remember to put RTV on the bearing cap mating surface? Perhaps you're getting a leak through there?
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Are you talking about the top part of the cap where the bolts go through? Basically on the tips of the U shape. If so, no I didn't, but it makes sense that RTV needs to go there now that I think of it. Is this significant enough to cause a 4-5 drop leak after I park?
 
One other area can leak and that is the oil pans end seal.
 
67-Conv-200":3swc2yvm said:
thesameguy":3swc2yvm said:
Did you remember to put RTV on the bearing cap mating surface? Perhaps you're getting a leak through there?
Click to expand...
Are you talking about the top part of the cap where the bolts go through? Basically on the tips of the U shape. If so, no I didn't, but it makes sense that RTV needs to go there now that I think of it. Is this significant enough to cause a 4-5 drop leak after I park?
Click to expand...

The mating surface between the block and the cap. It's always good practice to trace the edge of the cap with a small amount of RTV and then bolt it in place. Just be sure not to squish any into the bearing. :)
 
@bubba I don't think it is the rear seal of the oil pan gasket since I don't see any oil dripping on the outside of the flywheel. It appears to be dripping down the inside. This seal will be replaced anyway when I get back at the rear main seal.

@thesameguy Thanks, I'll try when I get some time. I want to drive and enjoy the car for awhile before I take it back apart again.
 
I'm not seeing the picture you're referring (I don't think, anyway), but the bolts in question are the ones that retain the flywheel or flex plate to the crank. If you haven't had the transmission off, then they should be fine. However, it's possible someone in the past may have forgotten! You can use RTV or something like Permatex thread sealant... I like the latter, but it's personal preference. In any case, removing/reinstalling those bolts does require separating the engine from the transmission.

Just throwing stuff out, but is it possible the oil pressure switch or head or valve cover is leaking, and dripping down the back of the motor?
 
thesameguy":3avdz898 said:
I'm not seeing the picture you're referring (I don't think, anyway), but the bolts in question are the ones that retain the flywheel or flex plate to the crank. If you haven't had the transmission off, then they should be fine. However, it's possible someone in the past may have forgotten! You can use RTV or something like Permatex thread sealant... I like the latter, but it's personal preference. In any case, removing/reinstalling those bolts does require separating the engine from the transmission.

Just throwing stuff out, but is it possible the oil pressure switch or head or valve cover is leaking, and dripping down the back of the motor?
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The transmission hasn't been off, but I do know that it was rebuilt back in 2010. I only removed the plate on the flywheel between the engine/flywheel and found oil trailing down the inside of it. I'll try the rear main seal again and hopefully that corrects the leak. If not, I'll look elsewhere.

Thanks.
 
67-Conv-200":1ecoxsfc said:
Do you mean the 4 bolts that are removed in my picture?
Click to expand...

thesameguy":1ecoxsfc said:
the ones that retain the flywheel or flex plate to the crank...removing/reinstalling those bolts does require separating the engine from the transmission.
Click to expand...

Yes sir...those are the ones I was referring to...you can see two of their threads coming through the crank flange just behind the bearing cap in your pic...or the half dozen holes seen here


Probably a less likely culprit than the rear seal or rear pan seal...but as sameguy said, 'just throwing out' another possibility. Good luck (y)
 
If I remember correctly those seals have a front and a back side- are you sure it was installed in the right direction?
 
mustang6":1dhcdx4i said:
If I remember correctly those seals have a front and a back side- are you sure it was installed in the right direction?
Click to expand...
That was the first thing I thought of when I saw it was still leaking. However, I followed the directions on the packages and the side with groves went toward the engine so I am pretty sure it is in their correctly.
 
The seal lip points toward the inside of the engine , also let the seal protrude above the edge of the cap on the mating end 3/8" and same on upper half so the butt ends are not even with the cap mating surface. This also minimizes leaks.
 
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