Need to renew the front crank oil seal on a '91 350SDL.

M-B 602/603 Service Manual states the hub is pulled off the crankshaft journal with M-B tool # 103 589 00 33 00.

Is this tool an absolute must for this job?

Hate to start the work only to find that a special tool is required... but in many cases I've found that service can be accomplished without the special tools M-B lists in their service manuals.

From what my indy told me special tools are not needed. The issue is with the harmonic balancer, there is a dowel pin and it must be lined up correctly. Also, there must be a way to hold the balancer in a locked position. I believe an extension wedged against the the cover or oil pan would suffice. Torque on the front crank bolt is high, 320 Nm for a 602, not sure what it would be on a 603. I haven't done the job myself, so I'm going by what he's told me. It looks like I'll be doing this job soon on at least one of my three 60x engines.

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Brian Toscano

I am currently in rebuild mode on my 87 300D so my engine is out of the car. I had to remove the water pump pulley since the balancer slightly interferes when attempting to remove. The balancer/crankshaft bolt loosened easily with the right size socket and a long breaker bar. The threads were normal rotation. You must be able to hold the crankshaft in position when removing the bolt. I used a piece of wood to block the crankshaft journel, no problem. With the engine in the car, one way is to remove the starter and I believe MBZ makes a tool to lock the flywheel throught the starter hole. Otherwise, you may be able to go through the bottom of the bell housing cover and somehow lock the flywheel. Good luck!

FYI, I did not need a special tool to remove the balancer or the hub once everything was removed. The balancer came off by hand and with the hub I used a screw driver and tapped gently between the timing cover and the back of the hub. I was very careful and it worked OK. If you have access to a Kragen or Pep Boys they rent/loan tools and a universal balancer puller may work. You will have to use the balancer hex head bolts and I don't know if the there will be room between the radiator and engine.

I would not recommend prying off the damper. You can use a regular harmonic balancer puller with the correct metric bolt sizes. You remove the large bolt and the bolts that hold on the pulley. The generic puller has a cone bolt in the center and uses bolts through the outer holes of the puller threaded into the holes from which you removed the pulley bolts.

My puller I got from the Snap On man over 30 years ago. I simply use metric bolts in the pulley bolt holes.

If you don't have the puller, I expect AutoZone will loan you one for the deposit on the tool.

Replacing the balancer, as mentioned earlier, is a critical process and the pin holes must be lined up and then the pins tapped in place. Many an MB crankshaft has been ruined by cowboys that just slap them on and draw them in place with an impact wrench. This is a method that works on most domestic balancers, but often destroys the crank on an MB.

Hope this helps,

You're saying that after the hub is on there is a pin that needs to be tapped in? I know there's a key on the crank (or hub, can't remember which). Is that what you're talking about?

Thanks
David

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2000 Honda Accord V6 137k miles

1972 300SEL 4.5 98k miles

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