Howdy friends-

Please bear with me for a bit of back story.

I've swapped an OM617.95x out of an '83 300SD into a 1990 Toyota pickup. Before purchasing the engine, I started it and drove the car it was in around the junk yard. No unusual noises or anything. During install in the truck I removed the vacuum pump, and after reinstallation and restarting the engine, the pump knocked badly. Yanked the pump, started engine, no noise. Discovered excessive intermediate shaft play and replaced intermediate shaft bearing, bringing play back into spec. Replaced vacuum pump bearings, reinstalled pump, STILL KNOCKING. Argh.

I already have an electric vacuum pump and control switch on the way. I'm going to rip the guts out of the stock MBZ pump and use the case as just a cover to keep oil in and dirt out.

What could have I boogered up during removal and reinstallation to cause the VP to knock like that? Does anyone want the innards? Cover shipping and they're yours.

Edit: Thought I'd add, the electric vacuum pump(Audi OEM brake booster pump) and switch came to less than $100, much less than a new OEM MBZ vacuum pump would cost. It also will eliminate a failure point for this motor and still give me power assist for the brakes even if the engine should turn off.

Thanks for the info, I have my pump gutted & cutdown for looks/clearance.

Do you have a part number for the Audi pump? Or what year/model/trim is came from?

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

I have considered an electric pump as well. Are you adding a reserve tank for vacuum? Does the Audi pump cycle, or run continuously? Sounds like a neat mod!

Getting rid of the vacuum pump on the engine is one of the best things you could do. I have pondered it for years, but never did anything in furtherance of the thought...

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Did you just pass my 740 at 200 kmh in a 300SD?????

1978 300SD 'Phil' - 1,315,853 Miles And Counting - 1, 317,885 as of 12/27/2012 - 1,333,000 as of 05/10/2013, 1,337,850 as of July 15, 2013, 1,339,000 as of August 13, 2013



100,000 miles since June 2005 Overhaul - Sold January 25th, 2014 After 1,344,246 Miles & 20 Years of Ownership

How big an electric pump (i.e. how many CFM per minute) would we need on our cars (mine is and 83 300D)

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2012 Mercedes ML350 Bluetec 91K (hers)
2005 Corvette 55K (fun car)
2002 VW Jetta TDI 231K (mine)
1998 Volvo S70 T5 Turbo 196K (kids)
1994 Ford F150 4WD 249K (firewood hauler)
1983 Mercedes 300D 376K (diesel commuter)

I'm using a Pierburg electric vacuum pump off a late 90s Saab 93 turbo. I still need to gut the internal out of the stock vac pump. Right now its just capped.
http://i.imgur.com/T4GZv.jpg

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CENSORED due to not family friendly words

When you do pull it, make sure those hex heads are clean and you have 100% engagement. I had the motor on a stand and I still had to drill 3 out

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

If you have an Automatic Transmission the Vacuum Valve for the Transmission is a continuous leak. Even with a Vacuum Shutoff Switch the Vacuum may never shutoff unless the Vacuum Switch is set to go on at a lower Vacuum; and that could be below what is useful for the Brake Booster.
If you have a Manual Transmission I think an Electric Vacuum Pump would be able to shutoff.

If the Audi Vacuum Pump is the same as the one below it May get really hot.
My thread on an Electric Brake Booster Pump 12 volt Electric Vacuum Pump
http://www.peachparts.com/shopforum/showthread.php?t=296397

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84 300D, 82 Volvo 244Gl Diesel

Thanks 911, that looks a lot like the one I bought. I will have a shutoff at a certain vacuum level and the only thing it will be running is the brake booster. Duty cycle intermittent.

After it is installed give us some feed back.
Are you going to use the stock Toyota Check Valve?

One of the American Car companies is using a Similar Vacuum Pump but instead of being made in Europe it is made in Mexico.

My Volvo Diesel occasionally exhibits some Vacuum Pump deficiency.
I was thinking about T-ing in the Electric Vacuum Pump with a Check Valve (I have that already) and hooking the Vacuum Pump to a Switch so that when I apply the Brakes Pedal it turns the Vacuum Pump on and releasing the Brake Pedal turns the Vacuum Pump off.

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84 300D, 82 Volvo 244Gl Diesel

Yup, stock Yota check valve. Current plan is to wire/plumb it all up and run it and see how she does, and add a vacuum reservoir later if needed. I'll definitely report back and let everyone know how it goes. Might be a couple weeks or a month, this is an ongoing project and while I'm very close to getting it on the road under diesel power, life has a way of throwing curve balls.

This entire project has been 5 steps forward, 4 steps back, which makes for 9 steps to make one step forward progress. This vacuum system has been no exception.

Edit: Might wire in an indicator light in the cab that comes on with the vacuum pump. Being able to monitor how often and how long the pump is running might give me some indicator of a small leak or other impending problem that hasn't shown up in braking performance yet, and an indicator light will take up a lot less room on the dash than a vacuum gauge.

I've made a stab at guessing that here

More than you are likely to ever want to know about OM61X piston vacuum pumps

83.4 cm^3 per second at 750 rpm based on an 85% efficiency of an OM61X piston vacuum pump

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Bearings worn?

Copper PTFE piston ring deed?

Did you use a gasket between the pump body and the block / did you RTV it?

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Bearings were replaced, both the intermediate shaft bearing and the bearings in the pump. Made no difference.

Copper PTFE piston ring might be toast, though it wasn't knocking before I removed it and I didn't remove it from the vacuum pump when I removed the VP from the engine, just removed the pump and reinstalled. I did R&R it when I replaced the VP bearings. No difference in knocking.

I did use a gasket between the block and pump. Figured the thickness of the gap between block and pump was pretty critical for clearance inside the pump and drive mechanism and wanted to get it right.

I wish most people's guesses were as vague as your "guess" about necessary cfm for an electric vacuum pump to replace our mechanical one.

That distance is important - but I can't remember if there's a maximum distance the timing device can stick out of the block {specified in the FSM (I'll check)}...

...what's the condition of the roller coaster track on the timing device?



Err yeah sorry about the number it has a decimal point which gives the impression of precision - but - if you follow the link you can see how I got there => it is a guess I've just used numbers. If someone can measure this it will be a much better way.

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!