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

4x4_Welder · #76 09-21-2010, 12:34 AM

Well, I'm dumping my a/c so that gives me a spot for the pump and a belt to drive it. If you are keeping the a/c, though, it might get interesting.
There was a suggestion earlier to put it where the engine driven pump was, and that might be doable, if you don't have a fan as this is a pretty chunky unit.
Another option could be down low between the alternator and crank, run it off that routing with a longer belt.

funola · #77 09-22-2010, 12:39 PM

I want to remove my vacuum pump for inspection. Does removing the power steering pump belt make it easier?

Mark DiSilvestro · #78 09-22-2010, 12:51 PM

Quote:

Originally Posted by funola

I want to remove my vacuum pump for inspection. Does removing the power steering pump belt make it easier?

Yes

funola · #79 09-22-2010, 03:50 PM

Did a quick test of my 12V Gast vacuum pump. I removed the vacuum manifold fitting at the vac pump and connected the gast to it, no reservoir, no check valve. The 12V pump is just laying in the engine bay as shown and was on contantly (plugged into cig lighter.

Went for a short drive. Transmission shifted fine. Brakes was also fine except when I pump the brake pedal 4 times in succession I lose power assist. It is too hot in the eng compartment for the elec pump. I plan on more testing with it mounted in the trunk and adding a reservoir with a check in the engine bay.

Stretch · #80 11-25-2010, 01:35 PM

How are you all getting on with this problem? Has anyone got a solution yet?

I've nearly finished rebuilding my engine and due to the costs of a replacement vacuum pump I plan to be reusing the old one. Should I consider a rebuild before I refit it? (Assuming there isn't a safer alternative)

vstech · #81 11-25-2010, 01:43 PM

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

4x4_Welder · #82 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 · #83 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

auspumpen · #84 11-25-2010, 02:30 PM

Quote:

Originally Posted by sixto

Here's the driven end of a later 606 vacuum pump. No reciprocating parts in view.

I don't know if a 606 timer will slide onto a 603 (or 617) pump.

Sixto
87 300D

Unfortunately, the late vane-type of pumps require their own oil feed, which is built into the timing cover. It is a far superior design. Not sure why it took them so long to go with it, since VW used vane pumps starting in the early '80's.

Mark DiSilvestro · #85 11-25-2010, 07:01 PM

Quote:

Originally Posted by Army

How are you all getting on with this problem? Has anyone got a solution yet?

I've nearly finished rebuilding my engine and due to the costs of a replacement vacuum pump I plan to be reusing the old one. Should I consider a rebuild before I refit it? (Assuming there isn't a safer alternative)

After my '84 Euro 300TD's recent vacuum pump failure in Virginia Beach (fortunately, without additional engine damage!) I was able to buy a new Pierburg pump, through a friend of a friend that owns a small indie Mercedes rapair shop, for $300.
List price for a new pump is around $450.
If my pump's piston hadn't broken when the lever-bearing failed, I could have installed a $260 replacement lever-bearing assembly. There is also a seal kit for around $80, but a new piston isn't availible.
The part that usually fails, potentially causing severe engine damage, is the plastic bearing-cage in the original lever-bearin assembly. When it disintegrates, it allows the 12 bearing-balls to drop into the timing chain. In my case those managed to make it harmlessly through or around the chain into the oil-pan. Someone else on this forum claimed that he suffered major engine damage when the pump-lever actually broke apart and fell into the chain.
The replacement lever I looked at had a plastic bearing cage but it should be OK as it may take another 20 - 25 years for it to disintegrate. Meanwhile, the new pump I wound up installing does have a metal bearing-cage.

Happy Motoring, Mark

Mark DiSilvestro · #86 11-29-2010, 08:20 AM

I still think a substitute could be fitted by removing the factory pump and the it's drive cam. That would allow bolting a heavy plate directly to the block, where a belt-drive pump could be attached and aligned to run off the power-steering belt.
I haven't had a chance to visit the Pick-N-Pull to see if any '80s or '90s American vehicles used a belt-drive vacuum-pump. I seem to recall some '80s Oldmobiles or Cadillacs having them but maybe it was only the diesel versions. Those pumps may be pretty rare.

Happy Motoring, Mark

Stretch · #87 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 · #88 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 · #89 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.

funola · #90 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???