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hutchjc1

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Discussion starter · #1 ·
65 Fastback with a 93 5.0 and a T-5, looks like the rear main seal is leaking, we replaced it when reassembling the motor and trans but it seems to be leaking. Can it be removed and replaced with the motor in the car and pulling the trans etc from below ? Not quite sure how we could have screwed it up but it seems we did, not looking forward to having to do this......Anything I maybe missing to verify the leak ? It dos not look like it's from the oil pan as the drip is running down the engine side of the block spacer. Any suggestions ?
 
Yes, this can be done in the car but it is a major PITA.

Before ripping in to it, I would be darn sure where the leak is coming from...

Oil from a valve cover can wick down that way for example. I would clean everything and then dust the back of the engine with baby powder. Often this will show up the source.

Is this a new style 1 piece rear main seal? If so, borrowing the proper seal driver can be quite helpful.

Good luck,
-Rory
 
Check ot verify with a local machine shop but, a rope type rear main gasket is easier to install (in place) as compared to a convemtional- but they do tend to leak a little tiny bit (just a drop or two).
 
If it is the one piece design - one thing to be aware of is the tension spring can dislodge from the seal lip during installation - a good way to avoid this is to pack the seal with some kind of assy lube first - I have always used trans assy lube because it has the consistency of thick petroleum jelly (vaseline) and it seems to work well.

As for doing the job in chassis - yes it can be done, but you should take the advice given above and do all that you can to be sure that it is the rear main first.

Rear of the lower intake, the valve covers, rear of the oil pan, and even galley plugs could all have the appearance of a rear main seal leak
 
+1 for checking the rear seal on the lower intake manifold. Very, very common place for a 5.0 to leak. Make sure you check this and the valve cover gaskets thoroughly before condemning the rear main seal.
 
Discussion starter · #6 ·
That's the advice I am looking for ! Last thing I want to do is have to replace the main seal. as I said it is new and was installed out of the car so access was good. This gives me a couple of places to check before as said I "condem " the seal. I remember thinking when I installed the lower intake manifold, did you used enough sealant ???? That would be much easier !

Thanks for the ideas,
Jim
 
I've changed a couple over the years, but as has been suggested, be sure it is the rear main leaking before pulling either the transmission or the engine to get to it.

Perhaps my next comment is not as valid as it was years ago, but I think it generally still holds true.

A rear main seal that leaks prematurely (Before 10 years or 100K miles) is a potential sign of bearing wear allowing the crankshaft to move excessively.

Therefore I consider signs of a leaking rear main to be very important to resolve-not because of oil on my driveway, but because they can be a warning of upcoming failure.

Personally I would pull the engine rather than do it in the car. This allows me to pull the oil pan and inspect all the main bearings at the same time.
But if you are certain it is the rear main, you are comfortable not looking at your main bearings and you have the desire to work under a car, by all means pull the tranny.
 
Discussion starter · #9 ·
The motor came from a wrecked 93 Gt convert. I bought it from the ins. co. The p.o. had left info in it so I contacted him about the car. He reported no issues at all with the car, he was the original owner and had maintained the car to pass down to his son, car had a fair amount of work done to it ( bolt ons only ) He owns a black top business and shares a storage facility with a landscaper. One night some kids tried to steal the car, when they could not get it started they took a bob cat and rolled the car 3 times then picked it up and put it on his boat. 300k in damages in about 2 hours. Car was considered totaled, so i have no reason to doubt what he tells me as he did not sell it to me. It had just under 100 k on it when I got it and we did not start it in the 93 because they had bashed the column trying to start it and then cut up the wiring to try and hot wire it.

While we had the motor out we did seperate from the trans and replaced the rear main seal, while we were there we also dropped the pan to relace with the one needed to fit the 65, all looked good, so if it is the rear main seal I would guess it was not installed correctly, not that hard an install but murphy's law. I did look at the rear of the intake and it is dry, there may be some oil on the pan mounting lip but I don't think it is from that as it ( the oil ) is on the engine side of the block spacer, I would think if it was the oil pan it would not be on the spacer, but drip down from the pan ? I have to look closer at the area to see if I can see anything before decieding what to do. There does not seem to be too many choices to consider with the engine and trans together. I may look into the dye and black light to see if I can get a better idea of where it is coming from.

Thanks again for your time,
Jim
Sucks to be this close and have to pull it back out.....(possibly ) maybe I will get luck and it's the pan or something easier...
 
One thought, was the seal lubed good where it goes around the crankshaft and RTV applied to the outside before being driven into place? And keep in mind there are two types of one piece rear seals. Standard and I think it is teflon. the teflon you have to install dry. Yea, this goes against all conventional wisdom about wetting a new seal.
Also on the seal surface of the crankshaft there are small groves cut into it the redirect the oil away from the seal. if these wear down from the seal riding on them, it will continue to leak with a new seal.
Two other areas not mention to look at if you do get this far is the cam plug on the back of the block and the oil gallery plugs. See if any oil is seeping around them too. If it is the cam plug, you have to remove the timing cover and pull the cam out or forward to get the plug out properly. I saw a post on Corral.net that did not end well from a guy trying to change his plug without removing the cam.
 
The Dude - that is a great thread with a lot of good info and an EXCELLENT write up by the OP. One problem that was all on a 2 piece rear main (which can be replaced through the bottom) and this thread is on a late model 302 with a 1 piece rear main which requires the engine and trans to be separated by removing one or the other.

(unless of course there is a way to use a 2 piece seal in an engine that calls for a 1 piece design....though I would advise against because in IMO the 1 piece design is a better design)
 
Just how bad is this leak? I think I could live with a few drops every day for a long time as opposed to the job of replacing the seal...

And as noted above, there are no guarantees that the new seal will not leak too. If you just put a new seal in under the best possible circumstances (e.g. engine out of the car), either there is something wrong with your technique or something wrong with the engine. The odds of the seal itself being defective are astronomically low.

Good luck,
-Rory
 
I can't see the big deal about this.
If it's a 93 5.0 it's a one piece seal,drop trans,flywheel pop out the old one and install the new one,essy.
We allways used the ones from Ford with just a wetting of the seal area on the crank end. No extra sealant.
BTW the ford tool works great but the shop I worked in didn't want to spend the money on it,we just tapped em in with a smallish hammer.
 
I can't see the big deal about this.
If it's a 93 5.0 it's a one piece seal,drop trans,flywheel pop out the old one and install the new one,essy.
We allways used the ones from Ford with just a wetting of the seal area on the crank end. No extra sealant.
BTW the ford tool works great but the shop I worked in didn't want to spend the money on it,we just tapped em in with a smallish hammer.

I was wondering the same thing because it's really no big deal at all, UNLESS you go to all that trouble only to find it was the lower rear intake manifold seal which it usually is! The intake leak is extremely common and and can easily mimic a rear seal leak so make sure you actually need that seal before tearing into that thing.
 
Discussion starter · #16 ·
I will have a chance to work on the car this weekend so I intend to clean the area as well as I can and try either the powder of foot spray and see if I can get a getter idea of where it is coming out. I did look at the manifold and it looks dry as do the valve covers. I did read the post refered to above and for the record the seal we replaced was a one piece seal that was tapped / driven in from the rear of the engine, not requiring the crank mains to be touched. We did this as a while your there you should replace it but I don't think it or anything else in the area was leaking at the time. I do not specifically recall weather it was a dry install or if we used a bit of oil, I would think we did use some oil for lube. I will update as I get a little more info.
Thanks for the replies,
Jim
 
Discussion starter · #17 ·
Update

Had a chance to work a little bit this weekend, I cleaned the area well and let the car run for about 15 to 20 minutes. It looks like the oil pan gasket is leaking and dripping onto the spacer plate, I did a little more reasearch and I think I may have used a late model one piece gasket on the pan, I went out last night and got the correct gasket for the early model motor / pan and will try it this weekend. Other than that I need to adjust the hyd. clutch linkage and finish a bunch of small stuff and it should be able to see daylight ! Car has been apart for giong on 2 years, took a perfectly good runing car and had to change it....this is a sick hobby, I need medication.
Thanks for the help I will let you know if the gasket was the real culprit, asap.
Jim
 
Thanks for the update Jim - hope the pan gasket works it for you.

Had not considered using a late model style gasket on a late model block with an early (front sump) pan.
Can someone else confirm if this causes a problem? I am planning to do the same with mine during assembly.
 
Discussion starter · #19 · (Edited)
Mako, I did a search on one piece oil pan gaskets and there seem to be two different part #'s one for the "old" style oil pans like is needed in a vintage Mustang and the "new" type made of the ribbed pans out of the newer 5.0's. I am not sure I used the wrong one but I do think it is leaking so I will replace it with the correct one to be sure. I did re use the one on the car now, it was on the 68 302 I have and it leaked on it also and that is partly why I believe I may have the wrong one installed. We shall see I hope to replace it this weekend.
Sounds like we are doing alot of the same mods, I am using a F.I. 5.0 out of a 93 with a T5 and narrowed explorer rear, 3.73's with posi 4 wheel disks , hyd clutch etc.etc. the money pit.......
Jim
 
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