'85 300D Vacuum pump question - PeachParts Mercedes-Benz Forum

Bham617 · #1 11-03-2013, 07:00 PM

I am in need of a vacuum pump rebuild kit. I have searched and there seems to be kits available for 617 up to '84, and for for the '85 617. Does anyone know whether or not the VP changed in '85? And would the kits work from the earlier years? Any help or insight would be greatly appreciated.

Thanks

Charlie

vstech · #2 11-03-2013, 07:03 PM

I did not know the pumps since 81 could be rebuilt. I thought only the vane pumps were rebuildable....
what's in the kit to rebuild the "up to 84"?

Bham617 · #3 11-03-2013, 07:43 PM

Welll I have found some "online" byy Pierburg,but they run around $200

. These have a rocker arm but, no diaphragm. I have seen others that run around $17-20 with a diaphragm

. Are these pumps rebuildable? I have searched and found some threads that show they are. But, these were for '81 or '83. Just was wondering if the vacuum pump changed?

my123ca · #4 11-03-2013, 09:14 PM

Your vacuum pump doesnt have a diaphram. When i rebuilt mine, i used a kit similar to this 1985 Mercedes-Benz 300D Sedan - Emissions Equipment - Page 1 . You will also need the gasket above the link as it does not come with the kit. If you are going to rebuild the rocker arm also, you might as well buy a new vacuum pump.

Diesel911 · #5 11-03-2013, 10:29 PM

If you have a Piston type Pump there is 2 rebuild Kits.
One for the Piston and the Valves and another for the Arm and Bearing that faces the inside of the Engine. And, neither Kit comes with a new Check Valve.

When you buy both kits you have spent as much money as a New Vacuum Pump and the new one will come with a warranty.

Stretch · #6 11-04-2013, 03:21 AM

I've put quite a bit of information about the OM61X piston vacuum pumps here =>

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

There are links to other threads as well - in particular to the biggest one so far on the subject started by Beagle.

Bham617 · #7 11-04-2013, 05:52 PM

Ok, here's why I think I need to have my vacuum pump rebuilt was that my mechanic said I did. My car would not shut off, so, he said he disconnected the vacuum line to the break booster and he said that he didn't hear any "hissing". Now, from everything that I've read you would have to use a vacuum gauge to be able to see if there is vacuum. So, now I have a delimma. Should I try and get a "kit" and rebuild it, buy a new one, or get a vacuum guage and test it? Having looked at the thread that stretch posted it appears to be extensive. Any advice?

Thanks

Charlie

mach4 · #8 11-04-2013, 06:28 PM

Quote:

Originally Posted by Bham617

Should I ... get a vacuum guage and test it?

A vacuum gauge is an essential tool for working on these cars, so yes, get a vacuum gauge. Actually you'll want a mighty-vac, which is a hand operated vacuum pump with a gauge on it.

snookwhaler · #9 11-04-2013, 07:07 PM

Yea.... More than likely it is one of the check valves. There is a big one in the top of the pump that "screws in" from the top to the main vacuum line. Then there are a couple more behind the front cover.

I remember doing a "half as@ed" rebuild on mine when I had it. It is kind of a PITA to remove the front cover and replace the check valves and o-ring. BUT, worth it IMO if you are driving the car a lot. I got the kit off of this site. Call them! Talk to them! They will get you what you need.

You really need a good vacuum tester and gauge for this. Harbor Freight is good enough to fix the problem and get beyond it. Just don't expect the tools to last. They got a knock off Mighty Vac tool that is good enough for a couple years. It falls apart after that.

If you plan to keep the car, get a Mighty Vac (or equivalent). Or, start saving big stacks of cash to take it elsewhere.

If you took this particular car to a "so called mechanic" and "he did not hear any hissing".... You need to find another mechanic ASAP or start saving big stacks of cash....

That is not a mechanic. That is a "want to be mechanic". A real mechanic could have hooked up a vacuum gauge in less than 5 seconds on this car and showed you a reading. Then he could have pulled vacuum from the pump and in other directions to check various check valves in about 50 more seconds.

Seriously.....

whunter · #10 11-04-2013, 08:34 PM

Quote:

Originally Posted by Bham617

I am in need of a vacuum pump rebuild kit. I have searched and there seems to be kits available for 617 up to '84, and for for the '85 617. Does anyone know whether or not the VP changed in '85? And would the kits work from the earlier years? Any help or insight would be greatly appreciated.

Thanks

Charlie

The vacuum pump is 1981 - 1985.

All parts interchange.

Vacuum Pump Rebuild Thread

.

Diesel911 · #11 11-05-2013, 12:02 AM

Quote:

Originally Posted by Bham617

Ok, here's why I think I need to have my vacuum pump rebuilt was that my mechanic said I did. My car would not shut off, so, he said he disconnected the vacuum line to the break booster and he said that he didn't hear any "hissing". Now, from everything that I've read you would have to use a vacuum gauge to be able to see if there is vacuum. So, now I have a delimma. Should I try and get a "kit" and rebuild it, buy a new one, or get a vacuum guage and test it? Having looked at the thread that stretch posted it appears to be extensive. Any advice?

Thanks

Charlie

Yes, a Vacuum Gauge is best.

You might wonder where the Mechanics Head was. If you really have a Vacuum Pump Failure your Power Brakes will not work and you would have had to step really hard on the Brakes to stop;scary.

And, when that happed to Me it turned out that the Check Valve that Screws into the Vacuum pump needed to be cleaned. After removing the Check Valve and hosing it out with WD-40 it has been working for over 3 years with no issues.
(Others have removed the Check Valve and found the Valve parts in pieces; there is replacement Valves.)

The No or slow shutoff issue can be caused by Vacuum losses anywhere in the Vacuum System but more specific in the Shutoff Vacuum System lines and the Vacuum Shutoff Valve mounted on the Steering Colum Lock and the Vacuum Shutoff Valve/Servo on the Fuel Injection Pump.

In short these Cars can have a lot of Vacuum Loss issues not caused by the Vacuum Pump. However, checking the Vacuum Directly from the Pump is a good place to start.

If you invest in a Hand Held Vacuum Tester (a.k.a. Mighty Vac) you will have your Vacuum Gauge and a way to test the Vacuum Components on your Car because it has a hand pump on it.

Diesel911 · #12 11-05-2013, 12:14 AM

Here is where the Check Valve is located.

whunter · #13 11-05-2013, 09:09 AM

mityvac, MB diesel owners hero.

rhodes2010 · #14 11-05-2013, 01:17 PM

Where do vacuum pump check valve parts go ?

I just had my 400,000 mile 300SD lose vacuum and only get two or three
presses on the brake pedal until hard pedal sets in.

After a long highway run I get power brakes for like one stop (two or three presses).
Then hard brake pedal.

After reading this thread my first stop was take out the vacuum pump check valve.

Nothing inside, wide open - my question is, WHERE DO THE MISSING PARTS GO ?

I am afraid to hear the answer, because inside the pump is the only place to go.

It made me think that if I were to open the front of the vacuum pump I might find some small debris
that could be removed before further damage.

I did not do this, but headed off to the junkyard and pulled the only three
vacuum check valves they had.

One was missing the guts, the other two had the parts inside .

So I come home with two check valves.
One of them seems to operate as expected with me blowing through it
so that is the one I put in.

Drove the car about two miles, up to 50mph, got feeble brake response and
car does not shut off.

Did my 75 mile commute , and brakes are only slightly better
and car does not shut off.

I have not tested vacuum at any ports yet, taking it one step at a time.

If I eventually need a vacuum pump, disappointed. Either a kit for $150usd
or a pump for $300usd.
Seems kinda steep, at least for the rebuild kit.

Do these pumps go out often ? (of course I am at 400,000 miles).

The other valve, I sprayed WD40, cleaned it up, and it looks really
good and behaves like the other one when I blow through it.
Air is allowed to flow from small end to large end, air is blocked
from large end through small end.

Any advice on removing that debris , for preventative failures sake ?

Any luck with junkyard pumps ? The cars I got my parts from said
250,000 miles on ODO, and who knows if the ODO's worked.

Diesel911 · #15 11-05-2013, 06:05 PM

Quote:

Originally Posted by rhodes2010

Where do vacuum pump check valve parts go ?

I just had my 400,000 mile 300SD lose vacuum and only get two or three
presses on the brake pedal until hard pedal sets in.

After a long highway run I get power brakes for like one stop (two or three presses).
Then hard brake pedal.

After reading this thread my first stop was take out the vacuum pump check valve.

Nothing inside, wide open - my question is, WHERE DO THE MISSING PARTS GO ?

I am afraid to hear the answer, because inside the pump is the only place to go.

It made me think that if I were to open the front of the vacuum pump I might find some small debris
that could be removed before further damage.

I did not do this, but headed off to the junkyard and pulled the only three
vacuum check valves they had.

One was missing the guts, the other two had the parts inside .

So I come home with two check valves.
One of them seems to operate as expected with me blowing through it
so that is the one I put in.

Drove the car about two miles, up to 50mph, got feeble brake response and
car does not shut off.

Did my 75 mile commute , and brakes are only slightly better
and car does not shut off.

I have not tested vacuum at any ports yet, taking it one step at a time.

If I eventually need a vacuum pump, disappointed. Either a kit for $150usd
or a pump for $300usd.
Seems kinda steep, at least for the rebuild kit.

Do these pumps go out often ? (of course I am at 400,000 miles).

The other valve, I sprayed WD40, cleaned it up, and it looks really
good and behaves like the other one when I blow through it.
Air is allowed to flow from small end to large end, air is blocked
from large end through small end.

Any advice on removing that debris , for preventative failures sake ?

Any luck with junkyard pumps ? The cars I got my parts from said
250,000 miles on ODO, and who knows if the ODO's worked.

Well, I am not clear on the first question. You have a Check Valve in your Main Vacuum Line. That is the fat Plastic thing in the Line.

The Vacuum Pump itself has a Check Valve that is normally brass colored that screws in to the Vacuum Pump.

Then inside of the Vacuum Pump itself is at least 2 other Valves and maybe a third one.

When the parts of the Check Valve on the Vacuum Pump go the dump down inside of a cavity in the Vacuum Pump.
The parts fall into the yellow area in the diagram.