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Discussion Starter · #1 ·
I'm in the midst of replacing the rear main seal on my '07 Duratec 2.0 ZX5. I have a question as to how the seal sits on the end of the crank. Does the edge of the seal's lip sit facing the engine block or facing the toward the flywheel | bell housing | transmission ? See my pics below.....

This is a picture of the new seal -- Motorcraft P/N: 1S7Z-6A321-B.
The image on the left is the front side - the side that faces toward the transmission. The image on the right side is the back side of the seal - the side that faces the engine block.


This is a picture of the old seal. The image on the left is the front side. The image on the right is the back side - the side that faces the engine block.


This is a picture of the old seal compared to the new seal. You see the lip of the old seal is facing back toward the engine block. Is this the correct way for the seal to be setting? The new seal's lip doesn't point either forward nor backward. I think after using the installation tool (OTC 303-328), the installation tool would push the lip's edge so it will face toward the engine block .


This is a picture beginning to explain my question. Is the old seal's lip facing correctly? When the new seal is installed, does the edge of its seal need to be facing in the same direction while it's sitting against the end of the crank?


The below picture shows the installation tool installed onto the old seal. Is this the correct way to use the tool (see the right image in the below picture)? When I do dry-run installs by "reinstalling" the old seal using the installation tool, it easily installs the seal by settling the edge of the seal's lip toward the engine block with the lip resting against the end of the crank. Is that correct way to install the new seal?

The below picture shows the front side of both the new and old seals. You'll see the old seal (left image) has a felt covering over the seal whereas the new seal (right image) doesn't have a felt covering. I assume not having the felt covering doesn't effect the seal's sealing capabilities??


If I use the installation tool and replicate what I've done with it during my dry-runs, will I be installing the new seal properly?


Thanks a bunch!!
 

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Put the new seal in the same way the old one was cooked to form a permanent shape to. Usually seal lip facing in. Why? Inside of engine is under pressure and with lip that way the pressure is trying to blow the inward bent edge inside out, thus making the sealing better. If the lip were out toward trans then pressure behind it would lift it up even easier to leak oil, The lip on a seal generally faces toward whichever side has pressure in it. That being the crankcase there.

That is on a single lip seal, some have two, an inner and outer and those can be more confusing.

Your tool there not only centers the seal plate, it also pre-sets up the required lip edge tucking in to face inside. Lightly lube the outer edge of tool that goes into seal lip to then be able to remove tool without pulling seal edge back out. If you can slightly spin the tool on the way out that will help too, it makes the lip release off tool edge somewhat to float on the lube to not roll back out.
 

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Discussion Starter · #3 · (Edited)
@amc49 You’re awesome!! Thanks for the detailed explanation and confirmation...you’re the best!!

In addition to lubing up the tool with assembly lube, should I also put assembly lube on the inside of the tool so it will leave some lube on the crankshaft as I remove it from the crank?
 

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When the seal edge slips off the tool it will do that with whatever is still on it. You can use a drop or two inside though if it makes you feel better. No great amount, just slick the edge up.
 

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Discussion Starter · #5 · (Edited)
Slow and steady wins the race!! I slowly, and seemingly successfully, worked through this job of changing the rear main seal to fix a small leak dripping through the weep hole. It took me almost two months of the car being up on blocks in my garage. I worked on it as I got time here and there.

The biggest set back in time was working to reinstall the transmission case. Although I didn't weigh it, the transmission seems like it weighs ~75-80 lbs. It's an awkward weight with very little room to fit it back up into the engine bay.

I have two pieces of advice for anyone jumping into this job.....
1. Bag your parts and thoroughly document your teardown. I did exactly this and found it invaluable during my reconstruction. The bell housing uses different size bolts depending on their location. It would've been quite frustrating to try and figure out which ones went where if I wouldn't have 'bagged & tagged' them. There are some brackets that need to be labeled as well as you likely will likely end up moving them away from their original location. Remember to mark your shifter cables relative to their brackets to ensure they are placed back onto the bracket properly.

2. Use an engine hoist/cherry picker to pull the transmission case up to the flywheel through the engine bay rather than a transmission jack to press the case up to flywheel from underneath the car. I suspect there are those who are skilled/patient enough to successfully use a transmission jack but I just couldn't get it to work. Once I got a cherry picker, I was able to successfully pull the transmission up through the engine bay to the flywheel rather than pressing it up to the flywheel with the transmission jack.

The thing that most surprised me during the reassembly was that the face of the bellhousing didn't naturally mate up against the face of the engine block after seating the transmission's input shaft through the pressure plate, clutch, and flywheel. After fully seating the input shaft, there was still ~1/2 inch gap between the two faces. I was easily able to get the two faces to pull together and successfully mate by fastening a transmission bolt onto the front side of the transmission (ie. front of the car side) and the back side of the transmission housing. Fastening those two bolts (hand tight) successfully mated the entire bellhousing to the engine block.

I dropped the entire steering rack with the subframe. I thought it was the less risky and easiest to do if I could get new seals when reconnecting the lines to the steering rack once the subframe was raised back into place.

Specialty Tools Needed....
I already mentioned the value of an engine hoist. An engine cross bar brace like this one was also essential to doing the job - at least if you don't want to have to contend with the space of holding the engine up from the bottom side. OTC 6895 crankshaft seal installer and OTC 6891 flywheel holder were also super helpful.

New parts I used during the reassembly:
  • Rear main seal: Motorcraft P/N: 1S7Z-6A321-B
  • Transmission motor mount: Motorcraft P/N: 5S4Z-7M121-A
  • Driver side ball joint pinch bolt: Motorcraft P/N: W712393-S439
  • Flywheel bolts (6): Motorcraft P/N: 1S7Z-6379-AAA (I put Permatex thread sealant on the threads prior to installing)
  • Power steering rack seal #1: Motorcraft P/N: 3L2Z-3F886-BA (this was for the silver / bottom line). The black steering line has a shield connected to it. The shield easily fits over this silver line when you button it all back up.
  • Power steering rack seal #2: Motorcraft P/N: 3L2Z-3F886-AA (this was for the black / top line).
  • Driver's side CV axle circlip: Motorcraft P/N: W700859-S403
  • Slave cylinder: Motorcraft P/N: XS4Z-7A564-AA
The power steering rack seals were more expensive than I expected. The were a little over $30 from one of my local Ford dealerships.

I used Permatex Ultra Grey RTV on the rear main seal. I ran ~1/8" bead of the RTV along the bottom, inside of the seal. I also ran a similar sized bead of RTV up along the inside, bottom-side of the seal. You'll be able to see how far I went up the sides in the first two pictures below.

One other thing..... I'm not sure if I lucked out on this but the shift arm on the top of the transmission was moved around quite a bit during the removal and install. I put the car in neutral prior to the teardown. When I buttoned everything back up, the transmission was still in neutral. I was able to successfully shift into all five gears and reverse. Was I lucky or does the shift arm not move anything inside the transmission? What's the role of the shift arm if it isn't to link the shifter inside the cabin to the gears inside the transmission?

Thus far I've put ~200 miles on the car with everything working as expected. Bleeding the clutch turned out WAY better than it did the first (and only) time I've ever done it before!! :)

 
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