Bell housing oil leak

[ChickenPinz]

I've had a slow drip at the bell housing weep hole for awhile. No signs of drainage down the side of the engine, so tonight I pulled the transmission to try to determine if it's the transmission input shaft seal or the rear crankshaft seal. Signs point to crankshaft seal.

Q: How hard is it to remove and replace that crankshaft seal once the flywheel is off?

Color points to it being Rotella 15W-40 engine oil versus the relatively pink MT-90 that's in the gearbox. I can't get much smell from the sample in the bell-housing, so that also points to engine oil, not gear oil.

Pictures below. More if people think it'll help confirm the culprit.

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[rmel]

Had to think about this one Although I've done this a few times,
I've always pulled the Valve Timing Housing off as well since there
were leaks near the starter motor due to the stress in that area.

So...when you pull the Housing off, the rear main seal comes with it.
That makes replacing a wee bit easier -but- then dealing with re-sealing
the housing a much bigger job.

If that housing seal is not leaking then to remove the rear main seal is
similar to the removal of the front seal which I did as well. All's that's
required is a seal puller with a paw and "flying" weight to whack it out
or wedge in a two leg puller with the paws facing out I've done it both ways.

Reseating a new seal can be a wee bit tricky, I did make a tool to "crank"
it in place on the front seal so it went in square and recessed the proper
amount. On the rear I did it in the housing via a press. But some sort of
Brass disk or some such to pound it in square is what I'd be thinking of.

[ChickenPinz]

Thanks for the insights. I'll pull the flywheel and see how things look. Sometimes it's tricky when something's been leaking for a bit to figure out where the oil might be coming from.

If you have more detail on the tools to remove/re-install the seal (or care to loan them for a day), pls let me know, either in-form or DM. Parts are on order.

Thanks!

[rmel]

Your more than welcome to borrow what I used to pull and replace.

However if you want here's the one paw puller ala AMZN https://www.amazon.com/gp/product/B008M ... UTF8&psc=1

The two legged puller was a kit from Hazard Freight.

I'll look in my "Makeshift" collection of hockey tools to see if what used on the front can be used on the rear -- stay tuned.

[rmel]

Found the "Installer"

Collars I used to "crank" in the front seal. More or less shims
with a thick Aluminum plate I placed a washer on and used
the threaded front crank to screw in place square. I don't
see why these can't be used with a rubber hammer to nudge
the rear seal in place.

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[ChickenPinz]

This was an interesting video: https://www.youtube.com/watch?v=vVDvEE_Hbm0 His technique is to screw a sheet metal screw into the old seal to remove it, and it looks like he didn't have much luck with the hook-style puller (like this: https://a.co/d/7iSEol9).

How have others pulled this rear seal?

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[rmel]

Having watched that video, IMHO DO NOT drill into the seal, any chips/debris
could end up in the sump or get into the front bearing journal, not to mention
the cam gearing.

Also it's far better to buffer knocking the seal in place with a ring or plate and
do NOT bang on it directly. If it goes in rod-eyed your more screwed than you
think. Proper seating is down "slightly" below flush -- in line with the slight
45 degree chamfer.

[ChickenPinz]

Does anyone have a photo of the area where the seal goes with the seal not in place?

[rmel]

Just a few more comments on this topic, having looked a little deeper into a few things
and realized some of my prior comments need a little clarification.

As I stated before I've done two of these rear seal replacements BOTH by removing the Cam Timing
Housing -- needing new gaskets. If you go that route extraction and insertion is easy. So I want to
develop my thinking here a little more on a "remove" the seal ONLY path.

The front seal is a SKF 75mm x 95mm x 10mm HMSA-10 RG. These are dual lip. One to retain oil the
other prevent dust/grime ingress. Once removed the gap from the outer seat edge to the crank flange
would be just under 10mm.

The gap between the Nitrile material skirt of the seal and the Crank flange is tight, more so than the
front Seal. The seal remover tool can't be too hefty otherwise you won't be able to squeeze it between
seal and crank flange.

What I'd be apt to do is get a Scalpel and cut the Nitrile skirt all the way around and remove it and the
internal expansion spring to allow a tool to be inserted with less interference, then yank at 12, 3, 6, and
9 O'clock until it pops. The seal is molded around a metal retainer so you can't cut that just the outside
part of the skirt that faces the Crank flange. I've also seen someone in the past use a dull Screw drive
in there and pry towards the crank flange, going around until it pops. I can tell you that having removed
two on the bench in the Can Timing Housing they are in there tighter that y'd expect.

In any case w.r.t. removal I'd also heat soak the Aluminum housing with a heat gun to a moderate temperature
to expand the socket the seal sits in as much as possible but not to the extent the Nitrile gets compromised.

With respect to insertion. Again I would avoid banging on the seal directly use something to spread the force
over a larger area. A 3" Schedule 40 PCV pipe has an OD=90mm and ID=77m, de-burred and square surface
could make a decent "whack it tool". Or at least to the point where the oil seal lip gets on the crank flange.
I don't recall if the flange has a 45 taper to receive the seal lip or not -- which may be insufficient to guide
it over the flange. I've used a tapered plastic cup cut to fit over the flange and greased up to the lip slides
in place. There are also seal skirt setting tools that are dull and won't do damage.

My remaining $0.02 on the topic.

[ChickenPinz]

I'll pull the flywheel in the next couple days and see how things look behind it. I picked up an induction heater for the bolts. Last time I used a torch and it definitely wasn't a fast process. It's partially an excuse to buy a new tool.

My biggest fear is that it'll be unclear if the leak is from the crank seal or the cam cover. All is TBD pending flywheel removal. I'll first photograph it and then clean it up before digging into the crank seal which arrives tomorrow along with the new bolts.

I ordered the Lisle 58430 - Lisle Seal Puller to give a try -- that's my first strategy. And I agree, that it makes sense to remove the rubber & tension spring beforehand. If that fails, I'll try other hook methods.

I've also mused about tack-welding onto the seal surface as a somewhat last resort. And I agree that drilling would be risky unless one could be certain that it wouldn't introduce any shavings into a place they couldn't be removed from with 100% confidence. I'm also tempted to use Freon to shrink the seal to loosen it.

Thanks for the extra notes!

[ChickenPinz]

For the curious, this is what the new rear main seal looks like. A magnet confirms there's ferrous metal under the plastic exterior.

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[ChickenPinz]

Flywheel's off. No bolt heating required. Used DeWalt DCF899H + 5Ah battery.

Bottom of the seal is wet, and the rest of things look dry (see photo), so I'm going to pronounce the seal as the source of the leak. And I see a drop of oil hanging on a casting boss on the right just to the left of a large nut, further incriminating this seal.

I'll try the Lisle #58430 puller first.

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[Puty]

I would recommend replacing the timing cover gasket (7101010141) as well.
This is a simple task and you don't need to purchase any additional tools to remove the rear main seal when you take the cover off.

Remember that there is an additional metal cover/thrower (7101020201) on the crankshaft. Just be careful not to damage it when removing the rear main seal.

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