1976 300d front crank seal size is really weird - PeachParts Mercedes-Benz Forum

oilsucker · #1 07-04-2011, 01:22 PM

Please help, I'm almost freaking out with this. While doing my water pump replacement on my 1976 300d, I thought I'd do the front crank seal, too. After pulling what I'm assuming to be the original seal, the replacement has a larger diameter. The old seal is an elring with markings: 3 45 71 10/14.5 The new seal has a 74.5 diameter/old one 71. I have talked with a dealership, two independents, and Peachparts....everyone is showing the new seal is the right part. I looked at some gas engine seals around the same years and they look just like my old one but with different sizes. If anyone has a clue, your input would be grateful.

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engatwork · #2 07-04-2011, 01:26 PM

Is there a "lip" on the new seal? What is the smaller od of the lip and the rest of the seal. Did you get it from the dealer?

Stretch · #3 07-04-2011, 01:28 PM

Welcome to the forum oilsucker.

Can you make a picture of the hole at the crank?

Can you measure the hole at the crank?

kerry · #4 07-04-2011, 01:44 PM

Fastlane shows same seal on your engine as later 617's. Maybe try the MB Classic Center. Is it possible that the sealing surface on your crank was worn and someone added one of those retrofit kits which puts a metal surface over the crank before a new seal?

oilsucker · #5 07-04-2011, 02:04 PM

Army, boy, do I feel like a dumbass? Your post got me to look again at the crank hole. What had happened was the inside portion of the seal came out and the outside ring stayed in the engine...see in the picture. My old seal just has a lip half way around, while the new one is completely around its diameter. Most parts pictures are showing the half lip...the new one was purchased over five years ago and I'm just now getting after it. Does anyone know if the pulley to balancer bolts have to replaced or just lock-tited?

kerry · #6 07-04-2011, 02:09 PM

I haven't heard of those bolts being replaced. You MUST perform sacrifices to all your local gods and any distant god claiming jurisdiction to assure that the dowel pins line up and your crankshaft nose doesn't get buggered.

ROLLGUY · #7 07-04-2011, 02:18 PM

Quote:

Originally Posted by kerry

I haven't heard of those bolts being replaced. You MUST perform sacrifices to all your local gods and any distant god claiming jurisdiction to assure that the roll pins line up and your crankshaft nose doesn't get buggered.

There was a thread somewhere here that a guy sheared both pins, and was able to replace them with no damage to the crank (or dowel pins). Very useful info on installing balancer hub. I remember also seeing another guy do a how-to on replacing the seal using a cone shaped plastic drink cup to guide the seal over the ring on the crank.

tangofox007 · #8 07-04-2011, 04:25 PM

[QUOTE=oilsucker;2746476Does anyone know if the pulley to balancer bolts have to replaced or just lock-tited?[/QUOTE]

Assuming that "replace" translates to "replace with new," I would highly recommend that option. This forum contains numerous reports of pulley bolt failure. Given the very low cost of renewing the bolts, I would consider that course of action, along with some blue Loctite, to be a "no brainer."

Stretch · #9 07-05-2011, 05:06 AM

One of the threads ROLLGUY is talking about has been turned into a DIY and is here:-

http://www.peachparts.com/Wikka/OM617CrankshaftSeal

Take a look at this warning too just in case you have dowel pin problems

http://www.peachparts.com/shopforum/showthread.php?t=295471