With the dangers of a vacuum pump failure, I have been wondering about alternatives. I currently have an International 7.3 IDI V8 waiting on it's final home to be prepared, and got to looking at it- It has a belt driven, fully external vacuum pump. It almost looks as though you could make a bracket to mount that on an OM617, and never worry about catastrophic vacuum pump failure again. Just put a block off plate on the front of the timing cover, and your timing chain is safe.
Does this sound feasible?

yeah, it sounds reasonable. race cars have done it for years, no reason why you can't do it on an MB... of course, the MB one is internally lubricated by engine oil, and the belt one would be a dry type, or have a sump of it's own... so longevity may be compromised of the pump...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!

Depends on what you perceive the chances of "death by vacuum pump failure' to be! The reality is that it happens fairly infrequently, probably more on some engines than others also.

You'd have to source a dependable pump, figure out exactly where it would reside, fabricate some mounting and then change the drive belt situation to run it. Seems like more work than reward.

There are electric vacuum pumps available. OEM and aftermarket. I think that would be easier to adapt.

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Diesel-guy

I'm just throwing ideas out there- I know that on, for example, the 617 if the pump bearings fail then it'll put parts into the timing chain and the engine is then done.
The pump used on the 7.3 as equipped in Ford trucks is a very simple unit:

The picture is actually upside-down, but not a big deal as the only lube I am aware of is factory installed grease on the bearings. They vent to the atmosphere, and are intended to run constantly. If they do fail, then just use your manual shutdown and fix at your leisure.
On my swap, I am removing the a/c so I will have a spot and spare belt groove to mount something like this. I may go junkyard hunting and see what I can turn up. Until then, I'll just keep the original pump on it.

Part of the issue is cost.

Bunch of random thoughts I looked into.

I have a 1984 300D If I buy a new Vacuum Pump it will most likely last what is left of the life of the Car.
The of the self price of something like a comp cams Electric Vacuum pump is around $250 and on eBay there is a similar pump for around $190.
You can learn more about the Electric Vacuum Pump on Electric Vehicle sites (EV). There is a Swiss made Vacuum Pump they are using but it is around $300.

Adding an electric Vacuum Pump might mean upgrading your Alternator; more expense.

There is also an internet parts seller that sells Rebuilt Vacuum Pumps (84 300D) for about $200[just got back from checking; the price has go up to $239]. I am not sure what type of core charge or shipping is needed to total the complete cost of one.

If some one has an extra Cylinder Head from a Station Wagon it might be a Vacuum Pump could be driven out of where the Hydraulic Pump used to go.

If your AC is shot you could remove the AC Pump and use it as a place to mount a Belt Driven Vacuum Pump.

On of the Japanese PU Truck companies had a Vacuum Pump Driven off of the end of the Alternator Shaft.

About a year and 1/2 ago I bought a Thomas 12 volt Vacuum Pump to attempt using it but never did anything partly because you need a 30 dollar or more Vacuum Switch to keep it from going all of the time.
but, it helped me bleed my Brakes.

Maybe Vacuum Pump failure can be prevented.
What in particular causes vacuum pump failure?
What in particular causes vacuum pump failure?

New Vacuum Pump Ruined due to too much Timer Shaft End Play (the title from my notes).
second vacuum pump, help! on a trip-Toronto

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84 300D, 82 Volvo 244Gl Diesel

How is the vcuum pump driven? Got pics?

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85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

I remember seeing one of the belt-driven vacuum-pumps, similar to that Ford unit, on an '80s RWD GM, possibly a Caddy. IMHO, the failure on the OE MB Pierburg pumps is caused by the original plastic bearing cages becoming brittle after 2-3 decades, breakng-up, allowing the balls to roll to one side and off-centering the bearing. The balls then fall out of the widened bearing-gap into the timing-chain area. This happened to me two weeks ago, but by some miracle, there was no apparent damage to my timing-chain or gears.
Initially, I got a Pierburg lever repair kit locally for $260, but my pump wound up needing a piston. So I was able to find a new Pierburg pump for $300 (They're normally around $450) The new lever repair kit had plastic bearing cages, while those in the new pump were steel.
Next time I'm in the Virginia Beach Pick-N-Pull, I'll look for other vehicles with belt-driven pumps.
But I wonder if a NEW vacuum pump for a Ford or Caddy might not cost as much as the OE ones on our diesels. Same for the cost of a suitable, new 12V electric vacuum pump as well.

Happy Motoring, Mark

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DrDKW

The new pump I posted the picture of is $130, a junkyard pump is about $50 with the pulley and whatever bracketry you can pull.
I'll try and get a pic of the stock setup later, but it's just hung low on the right side of the engine by the lift pump, and driven by a belt off the alternator.
The 7.3 turns 3400-3800 rpm, and has a much larger lower pulley so it actually spins the belts faster than the OM617, so the pump should be good for the higher rpm of the Mercedes diesels as well.

I had forgotten about that....and I had one. It was a 1984 Toyota pickup with the 2.4 L diesel, LN56 I think. It had the vac pump driven off the back of the alternator.

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'98 E300 DT
'87 190D 2.5 turbo RIP
'92 S500 Sold
'03 3.2TL-S A-Spec

Looks like I have to retract a statment.
I just went and looked at the internet parts seller that USED to sell the $195 rebuilt Vacuum Pumps. They are now showing a price of $239.00. 3 months ago the price was $195.
Looks like by the time I need one they rebuilt price will match the New price.

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84 300D, 82 Volvo 244Gl Diesel

I wouldn't use any used/rebuilt vacuum pumps that use the original internal parts, too much risk.

Regarding the "alternatives" - no comment.

Does the Ford pump provide vacuum for the brakes? Our Chevy 6.5 has a belt driven vacuum pump for emissions devices but the brake booster works off hydraulic pressure from the PS pump.

So another alternative is to use a tandem pump and a hydraulic brake booster

Sixto
87 300D

Yes.

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'86 300 SDL '83 300D Astral Silver/Blue
354k miles.. 326k miles..

http://www.peachparts.com/shopforum/...ine=1310252049

Yep, the older 7.3 IDI n/a and Banks-turbo powered (1994 and earliest 1995) and 7.3 TDI Navistar-powered Ford trucks to 1997 used this style belt-driven pump to drive all vacuum components, including vacuum booster brakes. It was very reliable. 1999- went to Hydroboost for brakes and electric for dash HVAC and 4x4 function if equipped. I have seen my share of pump replaced over the years, but given the number of trucks out there at the time and after a while, not many of these pumps have been replaced. So, they're pretty rugged. Make an adapter bracket and let 'er eat! Good thinking.

So is it my understanding, then that the MB vac pump design has nothing to do with the timing device and IP? If not, how do the bearings grenade and find their way into the timing chain? Is it through exposure to the oiled back side of the VP? Forgive me, I have never had one apart.

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Thanks,
Mark in NC

"Spark plugs?...We don't need no stinking spark plugs!"
1985 300SD "Der Silberne Schlitten" 420,000 mi


Wish these were diesel:
2003 Ford Club Wagon 130,000 mi