broken key in chain drive gear on crankshaft
 

Greetings:

I have somehow been suckered into helping my brother with the re-assembly of his 91 560SEL after a botched chain replacement.(Yes I admire him for trying), but explained to him that beer drinking(with friends) and engine timing chains is not a good nor productive way to go about this amount of work.
He has proceded in breaking a chunk out of the front chain cover(from prying it off(over the phone I tried to explain that prying on aluminum sealing surfaces is never a good idea). It appeared that the oil pump chain was holding the chain cover on, and after removing that the cover was free to be replaced in the recycle bin.
The issue I noticed was that the crankshaft key that is keyed thru the chain gear(on the front of the crankshaft) and front hub(also keyed to the crank)is sheared/broken off very close to flush with the chain gear on the front of the crankshaft.
Is the toothed gear removable? If so, is there a recomended tool to facilitate removal at the home garage?
Thanks

OUCH!
 

If you're saying that the Surgeons broke the "Key" that fits in the semi-circular
slot cut into the Crankshaft for it,leaving a portion in the slot?
Aerokroil and a "Nail Tap" with a light hammer blows to try and drive the remains
out.BE VERY CAREFUL...You're skirting with buying a new Crankshaft if your
fingers slip!

There is a BOLT that holds the HUB onto the Crankshaft,
you have to first remove the bolt (Well,First you have to lock the Flywheel
with the proper tool)
I would follow MB's directions on removal of the HUB[Factory Service Manual].
The Sprocket can be pulled off with a gear puller.

All this assumes the Surgeons haven't Bunged Up both the Hub and Sprocket.

brainiacs....
 

The crankshaft keyway is fine, but the chain gear and hub should be replaced due to deformation of their keyways(in my opinion). The gear is easy to find along with "normal" repair and maint. parts from work.


I have suggested that he consider a used comeplete engine due to the damage to the hub, and lower chain cover(which my civilain work does not carry). Not to mention any other hidden damge that may have occured.

It is unfortunate, this was a very nice example of an older but not too old Benz.