Hello everyone,

Until a couple days ago, I thought that all OM603 engine mounted vacuum pumps with the four torx screws on the front cover had sealed bearings on the cam drive. This sealed design prevents ball bearings from entering the timing chain cavity in the unlikely event of pump failure.

Please examine the pictures in this thread. There is NO way to visually identify whether or not your "new style" vacuum pump has the sealed bearings by looking at it from the outside unless it has the latest Mercedes part number (000-230-31-65) on it. However, if you buy an OEM Pierburg pump instead of OE Mercedes, the part number will be ground off.

Below are pictures of the original (semi-exposed ball bearings) vacuum pump:

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Here's what the semi-new style pump looks like. Note the four torx screws on the front cover, but notice how the ball bearings at the cam drive are still semi-exposed - just like on the old original style pumps.

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Here is the latest style pump. It has four torx screws on the front cover, but notice how the ball bearings at the cam drive are NOT exposed.

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Lastly, here's a close up picture of the cam drive. The first picture is what you'll find on the original and "semi new" pumps. The second picture is from the latest version.

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I just had a "new" pump put on this summer. Thanks for the heads up.

Chris

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1987 300TD 309, xxx 2.8.2014 10,000 mile OCI


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That's really not good news.

The criteria using the Torx screws on the cover as evidence of the new design is clearly in error.

About the only certainty is to remove the cover and take a look to see what you have............

Can the cover be easily removed and reinstalled without removal of the pump?

Does anyone have a picture of a failed pump? What actually breaks?

The bearing fails and the balls from the bearing drop into the timing chain cavity. If you're lucky, they just fall into the oil pan, where you hope they don't get past the oil pump intake screen. If you're not lucky, they get into the timing chain at one of the sprockets, and destroy really expensive things. It's rare but it has happened. Photos of a pump about to fail are below, courtesy of Aaron:

The failure I see in the previous post is caused by defective bearings and not a bad pump design. The bearing should not fail in this way and I suggest that this entire bad pump design is really a result of some significant number of bad bearings getting built into these pumps. So if you have the newer pump with the screws, you should not worry because the bearings should be good. The bearing manufacturer is the one to blame, not the pump designer.

What's a 7.20607.24 have inside? The MB number appears to be 000 230 31 63. It's hard to read on the case, but I think that's the right number. This is in a 606.

In the "old->new" chart at:
http://www.msi-motor-service.com/download/pg_gesamtkatalog/data/pg_zz02_oldref_web.pdf,

it shows this number as old, with .74.0 as new. Does this mean that the part is the same, or that the .24 should be replaced with a .74?

Hi everyone, just signed up to this very resourceful forum to share some infos regarding vacuum pump.
I have a korean 4WD (Ssangyong Musso) with a MB licensed copy of the 602 as the power unit. (Can't afford the original stuff yet , please don't)


It has the new bearing inside, part no. should be 000 230 31 65.

Taking the rear cover of the pump off reveals only the back of the piston in the pump.

Taking the pump off the timing case is relatively easy, I removed the tensioner and guide pulley to get some room.


Unfortunately my vacuum pump failed (new bearing style, original Pierburg pump) due to a worn roller/timing gear surface, breaking the pump shaft at 195 000km. (can post some nasty pic's on request, from the pump that is )
Has that ever happend to anyone on a (orig.) 60* Merc. engine?
I heard that this pump can fail too because the screw holding the piston to the roller shaft gets loose, causing too much stress to the bolt, which than breaks.
MB changed the whole design to a rotary pump in later models.

I'm in the middle of replacing the pump, timing gear, chain and guides, tensioner and a few other bits.

Kind greetings from Australia,

Kay

Interesting, I have not heard of one of the updated pumps failing in such a manner. But I am sure some do...

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2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

I'm still a bit clueless (like usual) on what has caused the failure. The roller on the vacuum pump lost about 4mm of its diameter and worked its way into the timing gear.
I appears that the roller of the pump locks up (at least intermittently). Whether or not that is caused by a bad timing gear (made in Korea), too high rpm's of the turbocharged engine or just poor maintenance of the previous owner or a combination of things, I can't tell.
It is not a common failure on the Musso's, but looking into the issue for some time, it seems to happen more often than a failure of the timing chain.

Well its not a common problem in the US, heck a lot of the old exposed bearing pumps have hundreds of thousands of miles on them. I am trying to think and I cannot think of a new pump failure off the top of my head. I know of 617's that have failed, but no 602/3/6's.

I know those engines are copy's of Mercedes, but how exact are they? Did they use all the same materials? I guess thats the queston, if one wanted to order a crate engine from Mercedes it would be north of $10k US, so did the Koreans cut corners to keep costs down?

__________________
2016 Corvette Stingray 2LT
1969 280SE
2023 Ram 1500
2007 Tiara 3200

That might be the case, I personally have seen 2 other failed pumps and heard of about 4-6 more in other countries, a bit much for my liking.

Anyway, here a link to the updated rotary vane vacuum pump, which is not interchangeable with the piston style pump (has an oil feed and different adaption to the timing gear).