Electrical Vacuum Pump Conversion Project - PeachParts Mercedes-Benz Forum

mach4 · #1 12-20-2013, 02:14 AM

I thought I would start a thread on a project to replace the engine driven vacuum pump on a 617 engine with an electrical pump.

There are a number of donor options and in doing the research on possibilities I created a list of possibilities.

2005-09 Audi A8 Quattro [8E0 927 317]
2004-06 VW Touareg [8E0 927 317]
2001-05 VW Passat [8E0 927 317]
1998-01 Audi A4/A6 [8E0 927 317]
1999-05 VW Jetta [1J0612181B and D]
1999-13 Volvo (most) [31317445]
1999-03 Saab 9-5 95 [46 46 220]
1994-99 Saab 9-3 900 9000 93 [46 46 220]
2011-12 Chevy Cruz [13343961] * (Pump appears ok, the problem is with a switch)

In an initial trip to the junk yard I found a VW pump but it was way too expensive. Today I found one for under $20 so I grabbed it. It came off a Passat. Here is what they look like.

I haven't ordered the vacuum switch yet but will shortly.

Right now I'm working on a design for a bracket and will get the pump mounted up before proceeding with the switch and relay.

The reason for the conversion is to eliminate the possibility for the engine driven pump to spill it's bearings and take the engine out.

There are at least two ways to control the pump. The first is with a controller. This is one that is used to control vacuum in a CNC machine environment.

It's $95 and is available on the BuildYourOwnCNC web site.

The other option is to use a switch and relay. I'm leaning toward this switch, which is available from EVParts

Pictures and progress to come.

strelnik · #2 12-20-2013, 08:26 AM

Quote:

Originally Posted by mach4

I thought I would start a thread on a project to replace the engine driven vacuum pump on a 617 engine with an electrical pump.

There are a number of donor options and in doing the research on possibilities I created a list of possibilities.

2005-09 Audi A8 Quattro [8E0 927 317]
2004-06 VW Touareg [8E0 927 317]
2001-05 VW Passat [8E0 927 317]
1998-01 Audi A4/A6 [8E0 927 317]
1999-05 VW Jetta [1J0612181B and D]
1999-13 Volvo (most) [31317445]
1999-03 Saab 9-5 95 [46 46 220]
1994-99 Saab 9-3 900 9000 93 [46 46 220]
2011-12 Chevy Cruz [13343961] * (Pump appears ok, the problem is with a switch)

In an initial trip to the junk yard I found a VW pump but it was way too expensive. Today I found one for under $20 so I grabbed it. It came off a Passat. Here is what they look like.

I haven't ordered the vacuum switch yet but will shortly.

Right now I'm working on a design for a bracket and will get the pump mounted up before proceeding with the switch and relay.

The reason for the conversion is to eliminate the possibility for the engine driven pump to spill it's bearings and take the engine out.

There are at least two ways to control the pump. The first is with a controller. This is one that is used to control vacuum in a CNC machine environment.

It's $95 and is available on the BuildYourOwnCNC web site.

The other option is to use a switch and relay. I'm leaning toward this switch, which is available from EVParts

Pictures and progress to come.

Great idea! I am looking at putting a power brake booster on a 170D or 180D which have none.
Am also looking at front disc brakes.

cho · #3 12-20-2013, 09:01 AM

.

another cool project I might consider...out of curiosity...why do we
need to control vacuum pump?

edit: is it just a on/off so it is not runnin' all the time...lot of folks converting to ecars use similar solutions fwiw..
also good switch and relay 24+18 bucks

thanks

cheers
ChO

.

Mölyapina · #4 12-20-2013, 09:17 AM

Cool! Methinks I'll be following your lead soon... the VP in my 'SD has 211k on it, so I need to replace it anyway.

OM617YOTA · #5 12-20-2013, 09:22 AM

Looking forward to how you mount your pump and how loud it is.

I have that exact pump solid mounted to the inner fender and by golly the whole county knows when it kicks on. It's loud and a different tone from the engine, can clearly be heard above the straight piped exhausted and the usual diesel clatter.

Dan Stokes · #6 12-20-2013, 09:29 AM

Thanks for this post. I've been kicking this idea around but you have a prettier solution than I've come up with. I'll only need it for shut off in the S-10 but I want it to be fool proof (given my level of "fool" that'll be tough).

What is that switch used on? Is it something I can scrounge at PnP? And is the VW pump Diesel-only or do lots of Vdubs have them?

Dan

pawoSD · #7 12-20-2013, 10:01 AM

Quote:

Originally Posted by Jooseppi Luna

Cool! Methinks I'll be following your lead soon... the VP in my 'SD has 211k on it, so I need to replace it anyway.

211k? The VP in my 300sd has 321k and works fine....I'm not worried. I had it off around 280k and it was in perfect shape inside. We have several 617's with original pumps and high miles with 0 issues.

I think there's a lot of VP paranoia around here, how many have actually had one fail? I replaced the one on my OM601 with a new engine mounted one because the original had 250k on it and was the exposed bearing variety. The new one has closed bearings and has been working great for 6k so far...

JB3 · #8 12-20-2013, 10:05 AM

where is this mounted in the VW application? does it have a special mount to cut down on noise?

I want one too

Diesel911 · #9 12-20-2013, 03:58 PM

Quote:

Originally Posted by pawoSD

211k? The VP in my 300sd has 321k and works fine....I'm not worried. I had it off around 280k and it was in perfect shape inside. We have several 617's with original pumps and high miles with 0 issues.

I think there's a lot of VP paranoia around here, how many have actually had one fail? I replaced the one on my OM601 with a new engine mounted one because the original had 250k on it and was the exposed bearing variety. The new one has closed bearings and has been working great for 6k so far...

One of Our Members installed 2 New Vacuum Pumps and ruined both of the. The reason was the Timer Bushing was worn and when the Piston and Arm of the Vacuum Pump came down it evidently did not get stopped by the Timer Cam but hung on the Piston and cracked the Piston.

The Bushing issue seems to be the more common reason for the VP Failure on the 617.952.
There is no clear answer why the Bushing seems to were faster on some Cars then others. I suspect it has to do with the past owners Oil Change record.

Another issue one of our Members mentioned is that if you have been driving your Car a long time and have not fixed your Vacuum Leaks the Vacuum Pump is working more then it would if you leaks were cured. That might increase wear on the Timer Bushing.

I think the Oil Change issues is also why some people have a not of Timing Chain Strecth compared to others with the same milage.
But, thoses are guesses.

My question What in particular causes vacuum pump failure?
What in particular causes vacuum pump failure?

Diesel911 · #10 12-20-2013, 03:46 PM

Quote:

Originally Posted by cho

.

another cool project I might consider...out of curiosity...why do we
need to control vacuum pump?

edit: is it just a on/off so it is not runnin' all the time...lot of folks converting to ecars use similar solutions fwiw..
also good switch and relay 24+18 bucks

thanks

cheers
ChO

.

I used the same Electric Vacuum Pump (it is a Rotary Vane type Pump and there is no lube inside of it) and if it runs a long time it gets hot enough to blister your Finger.
A Vacuum Shutoff Valve may or may not keep it from Heating up. When the OP is done with his project and has tested it well will have the answer.
My thread on an Electric Brake Booster Pump 12 volt Electric Vacuum Pump
http://www.peachparts.com/shopforum/diesel-discussion/296397-electric-vacuum-brake-booster-pump-tested.html

The other problem is that if you have a Mercedes Diesel with an Automatic Transmission there is always some Vacuum leaking out of the Transmission Vacuum Valve on the Fuel Injection Pump so it is possible your Vacuum Pump may never turn off or only be off for a short time.

mach4 · #11 12-20-2013, 06:47 PM

Quote:

Originally Posted by Diesel911

The other problem is that if you have a Mercedes Diesel with an Automatic Transmission there is always some Vacuum leaking out of the Transmission Vacuum Valve on the Fuel Injection Pump so it is possible your Vacuum Pump may never turn off or only be off for a short time.

During the testing phase I will wire in a light that will tell when the pump is on as a way to determine what the actual duty cycle is in normal operation. This is one of the unknowns that needs to be tested.

I intend to carry a spare pump at least until the concept is proven. The way it's installed I should be able to swap it in about 10 minutes with just a wrench, a torx driver and a screw driver.

OM617YOTA · #12 12-20-2013, 03:49 PM

I have the EXACT same pump on my conversion. It handles all the vacuum requirements for the whole vehicle, and works just fine without heating up beyond design limits.

mach4 · #13 12-21-2013, 02:15 AM

Quote:

Originally Posted by OM617YOTA

I have the EXACT same pump on my conversion. It handles all the vacuum requirements for the whole vehicle, and works just fine without heating up beyond design limits.

But you're running a manual transmission if I recall correctly.

It is starting to look like the transmission vacuum bleed is going to put it over the limit for what the VW/Audi vacuum pump can handle.

I'd considered the VCV when I was planning the conversion and my assumption was that the amount of bleed was quite small and wouldn't be an issue. Guess that's the problem with making certain assumptions. My reasoning was based on the relative sizes of the vacuum hose servicing the brakes vs the size of the vacuum hose servicing the rest of the vehicle.

It turns out to be true that exhaust port on the pump is actually smaller than the ID of the nylon vacuum lines

This whole project is beginning to look more and more unworkable. The good news is that I've only got $20 and a few hours into it to this point.

funola · #14 12-21-2013, 09:36 AM

Quote:

Originally Posted by mach4

But you're running a manual transmission if I recall correctly.

It is starting to look like the transmission vacuum bleed is going to put it over the limit for what the VW/Audi vacuum pump can handle.

I'd considered the VCV when I was planning the conversion and my assumption was that the amount of bleed was quite small and wouldn't be an issue. Guess that's the problem with making certain assumptions. My reasoning was based on the relative sizes of the vacuum hose servicing the brakes vs the size of the vacuum hose servicing the rest of the vehicle.

It turns out to be true that exhaust port on the pump is actually smaller than the ID of the nylon vacuum lines

This whole project is beginning to look more and more unworkable. The good news is that I've only got $20 and a few hours into it to this point.

Have you tried adding a reservoir? If not, try it before giving up up. Make sure you have no leaks in the system. I think you have a custom engine shut off. Does it leak?