Vacuum pump alternatives - Page 6 - PeachParts Mercedes-Benz Forum

Stretch · #1 11-25-2010, 02:00 PM

Quote:

Originally Posted by vstech

an 81 eh... does it have the air return line on it or is yours internal?

It just has the one pipe coming from the side, you can see it in the attached picture on the right hand side

4x4_Welder · #2 11-25-2010, 01:59 PM

You can probably tell my opinion already, but I'd get the shrapnel generator off the engine.
I'm shut down on physical work for the winter now, so it'll be spring before I get around to actually doing this mod.

Stretch · #3 11-29-2010, 08:37 AM

Just to spur on the pioneers - I've just got some prices back from the dealer for vacuum pumps and the bits you can get:-

A rebuild kit for the mechanical side costs € 176.68 plus taxes

A rebuild kit for the diaphragm costs € 60.07 plus taxes

The vacuum pump itself costs € 303.17 plus taxes

You only get € 32.75 back for your old pump!

Now I don't want to turn this into a MB dealers charge a fortune whinge - I'm continually amazed that you can still get hold of these parts for these cars - you'll have a harder time getting hold of bits for a 7 year old French car EVEN IF you live in France!

Still it is a lot of money so an alternative may even save some cash as well as a possible way to stop bits from potentially flying into your engine.

vstech · #4 11-29-2010, 08:43 AM

many of the chevy trucks use belt driven vacuum pumps. likely the 89-93 models would have it. however, my 92 is all electric, no vacuum at all on the engine... so perhaps it's just the heavy trucks that use the Th400 transmission? that'd be the 87-91 25 and 3500's I'd guess.

funola · #5 11-29-2010, 09:25 AM

I don't think I'd trust mounting a belt driven vac pump with the (6?) small allen head bolts of the OEM vac pump. Army, it's been alluded to that the rebuild parts you can still buy may not be the same quality as the original pump, so rebuilding may be an iffy proposition. I think an electric vac pump is the easiest and least costly. I did a quick test with an elec pump and plan to do more when I find the time.

Mark DiSilvestro · #6 11-29-2010, 10:27 PM

Quote:

Originally Posted by funola

I don't think I'd trust mounting a belt driven vac pump with the (6?) small allen head bolts of the OEM vac pump. Army, it's been alluded to that the rebuild parts you can still buy may not be the same quality as the original pump, so rebuilding may be an iffy proposition. I think an electric vac pump is the easiest and least costly. I did a quick test with an elec pump and plan to do more when I find the time.

My idea was to fasten a round, 1/4" thick, steel plate to the block with the 6 small allen-bolts. Then attach the vacuum-pump to that with 3 or 4 larger fasteners - as needed.
The vacuum-pump I had in mind is fairly small & light, and shouldn't require that much tension of the belt. I would try to ride one side of the PS belt with just enough pressure to drive the vacuum-pump pulley.
As for rebuild-parts, the replacemnt lever & bearing repair-kit I found was a NEW part, made by Pierburg, manufacturer of the original pump. The $300 replacement pump I wound up installing on my wagon was also NEW Pierburg unit. No need for a core-charge.

Happy Motoring, Mark

Stretch · #7 11-30-2010, 05:22 AM

Quote:

Originally Posted by Mark DiSilvestro

The vacuum-pump I had in mind was fairly small & light, and shouldn't require that much tension of the belt. I would try to ride one side of the PS belt with just enough pressure to drive the vacuum-pump pulley...

Happy Motoring, Mark

I instinctively prefer the idea of a belt driven vacuum pump rather than an electric replacement - I guess this is partly because you may need to upgrade the alternator if you're continually running a pump - but mainly as the vacuum is used for power brakes it just seems "safer" to use a belt... this is probably an emotional response from a mechanically (rather than electrically) minded person though.

Mark DiSilvestro · #8 11-30-2010, 09:54 AM

I have a friend that volunteered to try and extract the bearing-races from the lever of my failed vacuum-pump. When my pump failed, the lever got a serious groove carved in it as it rode against the edge of the cam for several miles. So I wouldn't attempt to reuse it even with new bearings. However, if correct replacemnt bearings can be found, it might make sense to replace the 25 + year-old ones in an old pumo BEFORE they fail.
Again, I'm very lucky that the lever itself didn't break apart and drop fragments into my timing-chain!

Happy Motoring, Mark

funola · #9 11-29-2010, 09:29 AM

Quote:

Originally Posted by vstech

many of the chevy trucks use belt driven vacuum pumps. likely the 89-93 models would have it. however, my 92 is all electric, no vacuum at all on the engine... so perhaps it's just the heavy trucks that use the Th400 transmission? that'd be the 87-91 25 and 3500's I'd guess.

You stated all 89-93 Chevy trucks have belt driven vac pumps but you have a 92 that's elec???

vstech · #10 11-29-2010, 09:34 AM

Quote:

Originally Posted by funola

You stated all 89-93 Chevy trucks have belt driven vac pumps but you have a 92 that's elec???

what part of my notice states ALL trucks? I said MANY and I qualified it that MINE is not one of them. I should further qualify it by saying many DIESEL trucks from chevy, have them not the gassers of course...

Diesel911 · #11 04-08-2011, 10:30 PM

Found an Electric Vacuum Pump that I believe has enough volume to do the job. I drove around with it as the sole supplier of vacuum and everything worked normal.
However, my test was not conclusive because I had no vacuum Shutoff Switch, Check Valve or Relay to test it correctly. The Pump got too Hot running all of the time.

The other Electric Vacuum Pump suggested by Compress Ignite in the thread below was made for the job and has all of the electric goodies needed to regulate the Vacuum. However, it is an expensive Vacuum Pump.
The forums that have the most information on 12 Volt Vacuum Pumps are Electrical Vehicle (EV) Forums where people are converting regular Cars to Electric Power.
Here is my thread:

Having an Electric Vacuum Pump may also mean you need to get a higher amperage Alternator.
The question is Pay $350+ for an New Stock Vacuum Pump or pay $350+ for a new Electric Vacuum Pump.

If your AC is not working and you never plan to fixe it the other Alternative is to install a pulley driven Mechanical Vacuum Pump; a bunch on ebay. But, you would have to make the brackets and

rkpatt · #12 04-26-2011, 01:48 PM

Great thread . There is an example of someone using the Ford IDI vacuum pump on the benzworld dot org forums - search for "vacuum pump substitution"

http://www.benzworld.org/forums/w124-e-ce-d-td-class/1532745-vacuum-pump-substitution.html

Doktor Bert · #13 04-26-2011, 03:08 PM

All the old RWD Cadillacs from about 1979 through about 1997 had electric vacuum pumps. A $25.00 scrap yard item.

We rigged one up on a buddy's truck to fill his air bag system and it works great....Robert

Orv · #14 04-26-2011, 05:16 PM

Quote:

Originally Posted by Doktor Bert

All the old RWD Cadillacs from about 1979 through about 1997 had electric vacuum pumps. A $25.00 scrap yard item.

We rigged one up on a buddy's truck to fill his air bag system and it works great....Robert

Isn't that a compressor? Or are you suggesting using the input as a vacuum pump?

Diesel911 · #15 04-26-2011, 10:44 PM

Quote:

Originally Posted by Orv

Isn't that a compressor? Or are you suggesting using the input as a vacuum pump?

The Vacuum Pump looks slightly Different from the Compressor.

There are some GM Products (Cars in the 80s that had Turbochargers) that did have a Brake Booster Vacuum Pump.
The Electric (EV) Vehicles site have a list of the years and models.

I have looked several times at a Junk Yard and I never found even one of them.
Also it may need a Vacuum Switch and Relay but I am not sure on that?