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2002 BMW M5 E39 Dinan
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Discussion Starter #1 (Edited)
While I'm reluctant to post a full DIY due to me not being a professional mechanic; I did tackle the issue this weekend and got a little insight to offer. Figure more info out there is good, especially since I found limited information on 'front crank main seal' on the board/internet(s).

Removal steps: Undercarriage panels -> fan -> belts -> crank pulley -> harmonic dampener -> front main/crank seal

The beginning of the procedure is identical to changing the belts, you got to get the fan off, which there's plenty of DIY's for.
I removed the undercarriage panels for better access; I think it's a must.

For the fan, you'll likely need the BMW special tools-- the special long wrench to release the 32mm bolt on the fan and the 'water pump pulley holder' to hold the fan in place (prevent spinning) as you loosen the 32mm bolt. I used the 32mm long fan removal wrench and a really big screw driver, but it's tricky to wedge it there and I didn't want to hammer on the 32mm wrench to dislodge the bolt, since it's attached to the water pump and I don't want to damage the water pump. It is also reverse thread, so clockwise torque releases the tension.

To remove fan, I lodged the big screwdriver between 2x of the 4x bolts on the water pump pulley (seen on very top, in photo below).
Once the fan is off, it looks like this.


Follow the other DIY procedures to remove the belts, by torquing on the pulley tensioners (IIRC 13mm bolt) and belts can slide off.

Next up is the crank pulley, held by 6x hex bolts.

I marked the crank pulley position to harmonic dampener with a permanent marker. These bolts (after consultation with others mechanics) are said to be re-usable. During re-install I torqued them down on feeling until I got them little more than snug.

After the crank pulley is off, you are exposed to the harmonic dampener, which I didn't take a photo of. It's a solid metal heavy piece, it is not a wear and tear item. It's attached to the crank by 4 large reverse-torx bolts (you'll need reverse torx sockets and a breaker bar).

5x reverse torx bolts:

There's 5 bolts in the photo, because the 2nd bolt from the top is a NEW bolt from the dealer. On the new #2 bolt, you can see the washer is thinner and the thread part is shorter. I ended up re-using these old bolts because they are beefy, also consulted mechanics and they said they've never seen them stretch. During re-install I torqued them close to as hard as I could with a breaker bar (no extension) [ the engine started to turn over from the torque on the bolt], and called it a day; I didn't use a torque wrench since I shipped all my tools to Europe (where my car was supposed to be; a different story).

After removing the harmonic dampener, the front crank main seal is revealed, leaking like the Titanic (after Titanic cracked in half)..



Cleaned out the oil massacre with gasoline



So far everything's been easy; here comes the real challenge-- getting the crank main seal out (and then getting the new one back in).
Apparently there's a special tool for this, but I don't have it, or the patience to wait for it to arrive in mail.

The seal is real tight in there, being careful not to scratch or dent the engine wall or crank shaft, I tried couple things- First I tried prying the seal gently with a screw driver and the seal didn't budge. Tried cutting it with a razor knife, but that won't work because it's metal, coated with some hard plastic-y/rubber-y compound.

Here's the seal scuffed from my 'gentle' attempts.


I tried using these (paint can openers from Home Depot (free)) to try to pull the seal out but kept twisting the paint can opener's metal, seal is much tighter seated than this metal's resistance on the paint can opener tool.


This picture below isn't accurate 100%. The big screw driver was finally wedged in the 'rubbery' gap between the seal and crank shaft. Then the screwdriver's handle bar was twisted steadily, with force, still gently, toward the crank shaft and the seal finally popped out


I did scuff the edge of the crank shaft a little, with the screw driver. I would recommend using electrical tape (or something) on screw driver to prevent this. Should be OK though, nothing major.



Crank shaft with front main/crank seal removed.


The mangled old seal. The thing was in there tight.


Another random picture, for your enjoyment.




GETTING THE NEW SEAL IN:

Since getting the old seal out was a challenge, I figured using rubber hammer to get new seal in would be easier.. WRONG.
The seal offers serious resistance going in, even using Castrol Motorsport engine oil as lube, still could not get it in. Usually when the girls say "STOP", just reply with TAKE IT and thrust.. but the M5 wasn't having it; all the lube in the world won't help here, or even hammer in my case. There's not enough space to swing down there, where the sun does not shine This is a tight-*** hole.

Frustrated with bruises and cuts on my arms, I took a pause and went to chill out before I do something stupid (like scratch the crank or break the seal). Sat down for couple hours and smoked out and thought how to go about this the easiest. Then I found an old PVC 2-inch diameter pipe, which fits perfectly on the new seal, and cut a short segment off of it. Gears started grinding in my brain and was thinking how do I apply 'gentle steady strong pressure' to the seal, in order to push it in. Ran to the garage and created this improvised tool:



This solution, using the original bolts provide gentle steady strong pressure to slowly squeeze the seal in the hole. While Castrol Motorsport lube (around the edge of seal) is recommended, it is not necessary for this method (I think...).


The seal inserted properly, with no violence or screaming, cussing, etc.. no damage anywhere. Total control all the way in.


Another view of the 'gentle tool' for tight insertions.


Then it's the reverse of above procedure to put everything back together. Make sure you follow star pattern on the bolts carefully while putting on the harmonic dampener and crank pulley, and note there's a 'pin' protruding on the end of crank shaft, letting the harmonic dampener only go in one way. Also if you use a screw driver (& 32mm fan wrench) to remove fan clutch, check the water pump pulley bolt tightness)

Keywords: "I bought an M5, now its leaking oil, should I keep it?", "there's oil on the undercarriage panels, what do i do?", "help, oil everywhere", diy, crank, main, seal, front, leaking, leak, wet, wetter, wettest, oil, "can't get it in", "can't get it out", special tool, insert, remove, crank shaft, flux capacitor, "oil leak near where the food for the goblins that turn the flywheel around",

DIY at your own risk; life's a long game of risk.
 

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Nice job! One way of getting a tight seal out I've found is to CAREFULLY drill a small hole into the flat surface of the seal. Use a shop vac to suck away any swarf that maybe generated. Then screw in a small self tapping screw into the hole. Do this at two points on the seal ~180° apart. Then you can pry the seal out with pliers or such like. Great idea on putting the new seal back in!
 

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Nice write up.

I like it when someone with decent photography skills is capable also of writing a nice DIY, it looks so easy to follow.

Not like mine where i have zero camera skill or finesse and only i can just about see whats going on in the pics!!
 

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Nice work!! A real PITA job!

This is something I did recently--twice, because I mangled the installation the first time. Critical to use some sort of installation tool like the homemade one used here, the BMW version or otherwise. Otherwise it is impossible to get the seal in evenly.

Only point of warning: The harmonic damper bolts are stretch bolts and not designed to be reused. Moreover, they are installed with a combination of torque to a specific level (can't remember), then angle-torquing another 45 degrees IIRC.

--Peter
 

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Hi - Nice write up. When I did this, I got a seal puller ( Lisle part # 56920 - good to have around. ). It worked well - This was thin enough to grab from behind, and strong enough not to bend. I bought the press from BMW ( in my case a M73N v12 ). The press is also plastic like you used, and is a little easier, but that was a good solution.

RY
 

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RMS tools in action. Crank seal tools work in reverse, viz., slide seal over "nose" tool (installed in crank) first, then set depth with circular piece. With RMS, one installs the seal in the frame first, then slides over the nose tool. Made it all so much easier, particularly with the stiff Teflon seals.

--Peter
 

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