Oil covered Bell housing bolt

[Paulaner]

Hey there! I am in the process of refreshing my clutch and when taking off one of the 17mm bell housing bolts on the passenger side the longer one was covered in oil.

There are no visible leaks or anywhere...bone dry.

What could have possibly caused this?

 

[JMinPDX]

That’s weird. If the whole area is dry maybe it was put in that way during a prior service or seepage from an old leak from elsewhere? I realize that taking a “if it ain’t broke don’t fix it” approach is a good strategy, but while your in there at least inspecting the rear main engine seal is a good idea.

 

[Paulaner]

That’s weird. If the whole area is dry maybe it was put in that way during a prior service or seepage from an old leak from elsewhere? I realize that taking a “if it ain’t broke don’t fix it” approach is a good strategy, but while your in there at least inspecting the rear main engine seal is a good idea.

Already on my list of to-do while I'm in there. Seal already in hand. Will report an update once I get to taking off the flywheel

 

[e9Leveque]

Was it just the shaft of the bolt or was there oil along the outside? Perhaps an old leak that had seeped in, been addressed and had the external area wiped down but no one removed the bolt to clean the interior. I had a hose going to my oil pressure sender (I had mounted it remotely from the cylinder) blow and spray a bunch of oil along the side of the engine which dripped down. I cleaned everything that I could see but I suspect that there may be a few drops that made it onto some bolts that I’ll never find unless I remove everytjing

 

[Paulaner]

Was it just the shaft of the bolt or was there oil along the outside? Perhaps an old leak that had seeped in, been addressed and had the external area wiped down but no one removed the bolt to clean the interior. I had a hose going to my oil pressure sender (I had mounted it remotely from the cylinder) blow and spray a bunch of oil along the side of the engine which dripped down. I cleaned everything that I could see but I suspect that there may be a few drops that made it onto some bolts that I’ll never find unless I remove everytjing

Bolt shaft was wet with oil upon removal. Has me stumped as to the source. Will find out more once I remove clutch and flywheel.

 

[Paulaner]

Update: escaped for work briefly to zip off the pressure plate and flywheel. Leak seems to have originated behind the crank. Correct me if I am wrong but the rear main does not look to be leaking.
One of the flywheel bolts and back side of the flywheel also had some oil residue on it.

 

[e9Leveque]

Looks like old leak. If you’re changing the seals there that should take care of the problem since clearly not a massive leak currently. Make sure to grease the area along the release bearing mentioned in the blue book. I hadn’t done this first time and had to pull it back apart to lube that. Blue book says “lube to prevent seizing”. Not words you want to ignore.

 

[Paulaner]

Looks like old leak. If you’re changing the seals there that should take care of the problem since clearly not a massive leak currently. Make sure to grease the area along the release bearing mentioned in the blue book. I hadn’t done this first time and had to pull it back apart to lube that. Blue book says “lube to prevent seizing”. Not words you want to ignore.

Thanks for the reminder on the grease!

 

[Paulaner]

Thanks for the reminder on the grease!

Flywheel off to get resurfaced tomorrow. Excited to see it reconditioned.

 

[Pittraider18]

Looks like the rear of the m30 crank is not blind, meaning the holes go all the way into the crank case. Oil is likely slowly escaping thru the threads of the Flywheel bolts and leaking enough to cause discoloration. Doesn't look like nearly enough to warrant how much was on that bellhousing bolt you had removed though.

 

[Paulaner]

Flywheel is back from resurfacing. 0.75mm step. She looks pretty. Before and after pics.

 

[Paulaner]

Putting the little guy to work

 

[e9Leveque]

That’s a mighty clean-looking 4-speed there!

 

[sfdon]

Shade tree mini-mechanic!

 

[Paulaner]

Shade tree mini-mechanic!

He doesn't mess around! Next time we do this job hell be driving

 

[Paulaner]

Ready to start going back together. Shift tower painted and new bushings installed. Clutch slave cylinder rebuilt with BMW rebuild kit from my parts bin along with a new push rod, and shift selector refreshed with new ball cups and bushings.

Tomorrow will be pilot bearing, rear main seal, and engine mounts.

Then maybe clutch and final assembly over the weekend.

I have a metric mechanic "ultimate transmission" and apparently after speaking with Jim (owner of Metric Mechanic) these do not need new input, output, and shift selector seals. They were upgraded to viton ones at time of machining. These are lifetime seals from what I was told.

 

[e9Leveque]

Looks great! I put my 5-speed in last weekend, went easier the second time around. Good news for you about the seals, I guess that’s the benefit you get with a full rebuild. It will last the next 50 years

 

[Paulaner]

Looks great! I put my 5-speed in last weekend, went easier the second time around. Good news for you about the seals, I guess that’s the benefit you get with a full rebuild. It will last the next 50 years

I'm still suspect over the longevity of those viton seals but they are as advertised so far. Trans was sent to Metric Mechanic in 1984 and there are still no leaks so we'll see. If anything my son can deal with it when he is 12-15yrs.

 

[Paulaner]

New Genuine pilot bearing in clean. On with the rest of reassembly after the rear main