Main Seal Leak, Clutch Slipping

[vande17941]

My 230sl 4-speed has had a main seal leak that leaves a silver-dollar sized drip overnight after driving. The car use almost no oil, so the leak must be pretty much after I shut her down. It's no big deal to live with it.

I was pushing it about 80mph and got on it hard and had the clutch slip on me under max torque.

I DO NOT want to pull the motor to do the rope seal. How much of a chance is there that the clutch is oil-fouled or does the oil just drip out the bottom of the bell housing?

Someone with actual experience, please chime in. Thank you.

[Benz Dr.]

Your clutch plate is worn out or not adjusted correctly. You would need to remove the crank to replace the rope seal which means your engine has to be removed. I would live with the leak if it doesn't get larger.

[vande17941]

I really don't want pull the engine to do the seal...I can live with some drips for the next 20 yrs until I have to pull the motor.

How likely is it that a small oil leak would contaminate the clutch.  I figured it wouldn't because the flywheel is in the way...others tell me differently?

Also, when you say adjustment...you are just talkin about the usual slave and pedal free play, etc right? There isn't any magical adjustment to save me I'm guessing. Seems like it would just be a straightforward clutch  job.

[Tyler S]

A small rear main seal oil leak as you describe wouldn't be enough to contaminate the clutch to the point of it slipping. A failed trans input shaft seal could do that but then you would have trans fluid leaking. Not oil.
Yes check your pedal freeplay and where the clutch engages. Should be about half way in the pedal travel. If this checks out you are going to have to pull the trans and replace the clutch.

[ja17]

On your 230SL, you should have a bit of free-play adjusted at the clutch fork/slave cylinder rod when the clutch pedal is up. You may need to dis-connect the return spring to set the freeplay (2-3mm). Exact amount is not that critical as long as there is some free-play. If you have too much free-play the pedal may be slow or may not return at all. If there is no free-play the clutch may not fully dis-engage and the clutch may slip.  Later W113 engines with the later clutch and throw-out bearing design self adjusted themselves. These  had no return springs at all.

[vande17941]

Pulled the clutch....it was fried. And the flywheel had some hot spots. Replaced it all and resurfaced the flywheel. Luckly, no oil from the rope seal was anywhere near the clutch.

[Benz Dr.]

How did you resurface the flywheel? I prefer them to be ground and hope that's how you did yours.

[vande17941]

Heck if I know...I brought it over to the same machine shop I always bring flywheels to....he took a tiny bit of material  off....I guess it is like turning a brake rotor. I have never seen anyone do a flywheel any other way. Seems fine.

[Benz Dr.]

I only grind flywheels. Cutting one on a lathe will remove to much material because of hard spots in the metal. By the time you get into metal you can cut, there's nothing left to cut. 

[vande17941]

Uhhh ohhh......I guess it's too late now. But it feeels great and doesn't slip.

What exactly is a grind? And is that what should be done in all cases with all clutches?

[Tyler S]

A grind is done in much the same way a cylinder head is resurfaced. The flywheel is mounted horizontally and a tooling bit is used to machine the surface. Its a lot more precise as well   

[Benz Dr.]

The flywheel is mounted on a table that spins slowly. A cone shaped grinding wheel is lowered to the flywheel surface and one or two small cuts are made. The cone will grind the entire surface in one pass and it will also grind right though hard spots in the metal. A lathe will tend to bounce over these hard spots and too much material would need to be removed to get a flat surface in most cases. The grinder is also much faster.