I need to lock the crankcshaft on a 1989 420 SEL and takeoff that 27 mm bolt on the crankshaft!! It seems that last bolt on the water pump is behind the vibration damper, which is locked onto the crankshaft, at about 200 NM. I have the V-belt pulley off already.

Anybody have any ideas ?

Would a plate work from 1/2" plywood, and bolted on to the crank in place of the v-belt pulley. The plate would jam up against the top part of the oil pan.

I have read there are special tools but sirtools, samstag, don't seem to have one.


Help!!

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1989 420 SEL

here is a picture and part number of the tool. give mercedes a call or search on ebay, it may not be that expensive

I still haven't been able to find the tool or get the the harmonic balancer nut off. I saw that tool in the service cd but where do you put it to lock the crank?

Since I can't find the tool, I tried the starter method. I put a 1/2" drive 27mm (12pt) socket with a 48" black iron pipe on the harmonic balancer nut. I hit the starter, letting the pipe swing 1/4 turn until it smacked a 2x4. I had sprayed the nut with wd40 2 hours prior. First time the pipe went flying, and only hit the 2x4 gently. Second time I duct taped the pipe and wrench together. A real solid hit the second time, but it was still not enough to loosen the nut.

Has anyone loosened the big harmonic balancer nut using this starter method? Should I shorten the pipe and increase the swing to 1/2 turn? What's next?

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1989 420 SEL

Stupid question: I'm not familiar with your engine, but if it is similar to my 117 (560sl), the harmonic balancer is a chunk of iron that is NOT connected to the crankshaft, it is sandwiched between the pulley and crank flange and held in the sandwich by the pulley and bolts. It is "nasty" to get off, after a soaking in liquid wrench overnight, judicious tapping at 12,3,6, and 9 clock positions eventually persuaded it off (DON'T DO THIS until someone with better info responds!!). Anyone?

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86 560SL
With homebrew first gear start!
85 380SL
Daily Driver Project

http://juliepalooza.8m.com/sl/mercedes.htm

The last post is correct. The balancer is aluminum and is sandwiched between a shoulder on the crank and the belt pulley. Spray it with some penetrating oil and keep working it back and forth with a couple of pry bays being careful not to break anything behind it