[klhansen]

My clutch blew up last week, so have the tranny out, and while I was fixing the clutch, I figured I'd replace the rear main seal as well, because it was drooling enough to wet the pan near the starter motor. It's NOT coming from the valley, although the EBP actuator seal is leaking a bit (not enough to drip).

Anyway, I was going to stop by the International place on Friday to get a new RMS, but had too many other things going to be able to get there. Ford was open today, so I went there to get a seal, and the parts guy brings out PN F4AZ-6701-A which he said was the newest part #, having superseded one that ends with AA. When I saw it I balked, because everything I've read about says the RMS comes with a wear ring, but this one was a standard rubber lip seal without a wear ring.

So my question is, have any of you guys replaced a RMS with that type, or have you always used the one with the wear ring? Is the standard type seal superior to the originals or the seal/wear ring package?

Thanks

on edit: the # on my original seal is 1823404C1, but that doesn't cross over to any Ford #, and it's a metal ring seal while the new Ford one is rubber coated on the outer edge and contains no numbers at all.

 

[ford_doctor]

Seals WILL wear a ridge in the crank. I would never consider replacing the seal without a new wear sleeve even on a low mileage engine which yours is likely not. I am amazed that they would sell one that way for these engines at this point. Without any documentation as to why this seal is sold this way or why a sleeve is not included I too would shy away.

 

[klhansen]

Thanks, Doc

I was definitely leaning toward your way of thinking on using the wear ring. I'm at 140k miles, which is neither low or high mileage, but I definitely don't want to have it start leaking because of a worn crank. When I replaced the clutch ~4 yrs/40k miles ago the RMS had a touch of oil around it, but left it in place. It's not going to get better, so I'm going to see what Int'l has on Tuesday, or maybe check the parts places today. Most likely I'll be tranny-less thru the weekend till I can get this sorted out. I have other things to fix, which should keep me busy.

 

[klhansen]

Followup

I was able to get the right seal at NAPA and got it changed out. The original seal rode right on the crank and had grooved it, so the wear sleeve was definitely necessary.

Turns out the seal that Ford sold me wouldn't fit at all. I also searched the Motorcraft site and came up with the same number that "just the parts guy" did, so it appears that Ford's data is messed up.

The good part is that I get to return the $68 Ford seal. I was thinking that the local parts stores would say "no got", but was pleasantly surprised when they had the correct one in stock, AND got it for under $20. :thumbsup:

So the moral of this story is don't buy a RMS from Ford.

Here's some pics of the differences. The last two compare the diameters of the original and Ford seal. I think the Ford seal would slip right thru the original.

 

[ford_doctor]

I wouldn't say "don't buy a RMS from Ford" just because you had someone make a mistake. I think the real moral of the story here is to know what you need and know enough to know when the part is correct or not which you obviously did. Now if you are shopping price I can understand your choice perfectly. For me I might have stuck with the Navistar part but that's me. Did the NAPA seal come with a tube of the Navistar RTV silicone like the Navistar/Ford seal does?

 

[klhansen]

I hear you, about getting the correct part, but when Ford's own site leads you to the wrong part, that's a problem. Wnen I questioned the seal at Ford, he said "I'm just a parts guy". He was just blindly following the book. I'm going to take the part back along with the original and try and improve his education.

No sealant with the NAPA seal. It included a gasket, but I used Ultra Black on the mounting flange rather than the gasket.

I would have gone with International, but they are only open M-F and I needed to get the work done. Riding with the wife is too stressful. :worried:

 

[ford_doctor]

Does the Ultra Black Permatex meet the specification for sealants required for Power Stroke Engines? Your 7.3L requires Silicone Sealant F5TZ-19G204-AB or equivalent meeting Ford specification NAVISTAR SLR. Using the wrong silicone may disrupt the anti-foaming additives in thew oil and cause ICP issues... but we all know this at this point. Right?

 

[DozerDan82]

I found this thread while searching on replacing my Real main. I have been told I need a special tool, and now reading this see mention of a special sealant.

Can anyone spread some light on this. I have the napa seal that is shown above already. Was planning on doing it this weekend, Trans is out and rms does leak, not horrible but its all apart so I figured I would change it.

Anyone have any input.

Thanks
Dan

 

[klhansen]

What I used to press on the seal wear ring was a piece of aluminum hat section ( _|-|_ - best approximation I could do on the keyboard ) that I had laying around. I drilled a couple holes to match the flywheel bolts and relieved the center section to clear the center of the crank end (higher than the bolt seat circle). It went on real nicely by tightening the bolts evenly. If I had it to do over, I would have used steel, or at least some steel to spread the load around. It now has a small groove where the seal wear ring rode against it, but seated the ring all the way to the end.

I'll try to post a picture of my rigged up tool when I get home.

The "crown" of the hat is about 1" x 1" and the "brim" about 2" wide.

The sealant you should really use to be sure it's right is available from either Ford or International. Alternate PN is Motorcraft TA-31. I came as close as I could with the Ultra Black, which said "Oil Resistant", but I didn't have the luxury of waiting till I could get the right stuff.

 

[DozerDan82]

Got mine on, but did not have the right sealant, I used RTV, but may re do it with the right stuff before the trans goes back in.

I just cleaned up the crank with some light sand paper and evenly worked the new seal surface on. The hardest part was cleaning all of the old sealant off.

 

[klhansen]

Got mine on, but did not have the right sealant, I used RTV, but may re do it with the right stuff before the trans goes back in.

I just cleaned up the crank with some light sand paper and evenly worked the new seal surface on. The hardest part was cleaning all of the old sealant off.

Did you use something (sealant or loctite) between the seal ring and the crank? If yours slipped on easily, that would be a leak path if you didn't use anything to glue it in place.

If you're going to redo it with the right sealant, I'd get a new seal as well, as the instructions say not to disassemble the seal from the seal ring.

 

[DozerDan82]

Did you use something (sealant or loctite) between the seal ring and the crank? If yours slipped on easily, that would be a leak path if you didn't use anything to glue it in place.

If you're going to redo it with the right sealant, I'd get a new seal as well, as the instructions say not to disassemble the seal from the seal ring.

I got the right stuff from ford today, I am going to pick up another seal ($16 from napa)

The seal ring was definatly a 'press' fit, I used a bore mic and then mic on it all, and its a tight fit. I did put some rtv on it once I had it seated square, then pressed it on the rest of the way. I am going to pull at least the seal off again. Might leave the 'ring' on, if the tolerances are the same from the new new one I am going to get.

I should have just waited to do it, but was impatient so now I will redo it before I throw the trans up, if the trans ever shows up.

I did put some start up lube on the seal, so taking it off should not be an issue, I am more worried about bending the flange while getting it off.

 

[klhansen]

I did put some start up lube on the seal, so taking it off should not be an issue, I am more worried about bending the flange while getting it off.

FYI, the original seal from my truck had "DO NOT PRELUBE" stamped on it.

As far as getting the flange off without bending it, I got a cheapo putty knife and cut it down to about 3/4" wide so it would fit between the crank and the pan flange. That did the trick as far as getting the flange loose.

 

[DozerDan82]

FYI, the original seal from my truck had "DO NOT PRELUBE" stamped on it.

So did mine, but the new one did not, and I have put a lot of seals on a lot of applications, and a light prelube will keep them from burning up on start up.

 

[losfinch]

I'm about ready to do this myself next weekend and I'm getting a little confused on the right steps. I'll have the AT-31 Ford sealant and the NAPA BS40436 rear seal. That's all I'll need to replace the seal, correct? (I've got the transmission out BTW.) What are my steps and where do I put the sealant...just behind the flange? The should I put some of AT-31 on the seal as well where it rides on the crank or do I use some other type of lubricant there? I'm sure its simple but I'm out in the middle of nowhere and I've got to have supplies brought in on a plane and I really need to get things lined up ahead of time to avoid more down time.

Related to this is in regards to the rear plate...If I take it off am I pretty much committed to then removing the actual oil pan as well in order to get a good new application of sealant between the round part of the oil pan and the rear plate as they go down around the crank?
Thanks!

 

[klhansen]

I put some locktite between the wear ring on the seal and the crankshaft, which I recall the instructions from the NAPA seal suggested. I don't think I'd use the RTV sealant there, as it'd probably be too hard to keep it from oozing on to the seal proper. Maybe the Permatex Anerobic Gasket Maker that Ford uses for other things like the ZF-6 transmission shift tower. The locktite I used was a pretty heavy bodied stuff and I put a light even coat on the crank. The Ford service manual doesn't say to do that, as I guess they assume the press fit of the wear ring on the crank will take care of sealing between the ring and crank.

The instructions show a special tool set to press on the wear ring and seal (Ford #303-S485 or OTC # 7835) which contains a ring and forcing screw used to push on the seal with wear ring as a unit. But I used a home built tool that I posted a photo of earlier in this thread. I wouldn't try to tap the seal/wear ring on with a hammer as it's sure to get crooked and messed up. Using the flywheel bolts with my fabbed up tool worked fairly well.

 

[ford_doctor]

Anerobic Gasket Maker :thumbsup: