75 300D Vacuum problem - wet vac?! Video - PeachParts Mercedes-Benz Forum

1975300D · #1 09-04-2011, 04:15 PM

Hello everybody, I shot a short video of my vacuum issues and the car taking 3-4 seconds to shut off.

1) I have vac lines connected to washer lines and I need to correct this and get my system working. Maybe someone can recognize this bizarre set up.

2) I am getting only a fraction of the vacuum pressure at the fuel shut off valve. It does shut off the car but only after about 3-4 seconds. So I'm making progress!

Thanks for any advice.

VIDEO

1980sd · #2 09-04-2011, 04:34 PM

On my cars the large opaque/white vacuum line goes to a vacuum reservoir in the fender. I would check that out.

tomscat1 · #3 09-04-2011, 08:36 PM

OK, here ya go. I checked my 1975 for comparison. To correct what is wrong is quite simple really.

1) The hole you see on the firewall is the attachment point point for the three hose connector. No vacuum line or any other hose goes in that hole.
2) that three hose connector is only used for the windshield washer operation. You have two hoses connected properly now. The third nipple should have a hose from the nipple to the WW line that goes to the nozzles on the hood. This appears to be missing in your pics. You will need to replace that line.

3) That strange connection with the white piece is connected wrong. It is now connected where the WW nozzle line should go. Disconnect it. It SHOULD be connected to the line coming off the brake servo unit that presently has a drill bit inserted in it to close it off.

That's it.

The lines from the injection shut off valve to the ignition, and from the the other fork at the brake servo line to the ignition are correct.

I regret that I do not have a labeled picture to make this more clear, but I think it is fairly straightforward. To summarize, you need to do two things: a) disconnect the line with the white unit from the WW connector and reconnect it where the drill bit is presently inserted; and 2) add a line from the WW nozzles on the hood to the triple nipple connector for the WW washer unit that you just disconnected the white unit line from... Done.

Well, you are done with that part anyway. Bear in mind that someone may have connected those lines that way for a reason. It could be because they just had no clue what they were doing, or.... it could be because there was a problem of some sort, and this arrangement----screwy as it may seem to you and I---- somehow solved the issue. So, if putting all these things right still leaves you with a problem, that may be the original issue that needs to be fixed. It looks to me like there was a vacuum issue somewhere, and this was gerry-rigged this way to make it work.

Hope this helps.

1975300D · #4 09-04-2011, 10:46 PM

Tom, am I confused now!

You say that no hose should go into that hole in the firewall, but we need a hose there to take fluid from the pump, right? What is on the other side of that hole - just empty space, right?

When you talk about a three nipple connector, are you talking about the thing with the white round thing? Which nipple is the third nipple?

Mark

tomscat1 · #5 09-04-2011, 11:12 PM

NO.

The three nipple connector is the thing that looks like it has a bottlecap on the top. There were some pics of this somewhere. Was that on a different thread? Can you post that pic again?

See #2 above.

I also posted a pic of that connector on my car showing it attached to the firewall where it belongs. Where did those pics go?

1975300D · #6 09-04-2011, 11:43 PM

Tom, you mean this pic?

kerry · #7 09-05-2011, 12:07 AM

Ok, I watched your video. The fact that the engine doesn't shut down promptly after running that short a time is no surprise to me. Any small vacuum leak in the system will draw down the reservoir and it takes a while to build it up. Let the engine run for 5 minutes and then try it. Also, with the green and yellow lines disconnected and apparently all screwed up with the windshield washer system may mean that the reservoir is no longer even hooked up. Get a vacuum reading off the T of the main line where the shut off lines leave the main line and report back. Someone with a 115 is going to have to tell you how to straighten out the mess with the yellow and green lines but they are irrelevant to the shut off system except insofar as you may no longer have a reservoir. On a 123, yellow lines are the door lock system and green lines are the climate control system.
If I understand Tomscat1 correctly, the windshield washer system and the vacuum system should be not connected to each other and the vacuum line which is currently connected to the windshield washer system with that white thing in it should be hooked in to where the screwdriver bit is.

tomscat1 · #8 09-05-2011, 10:58 AM

Quote:

Originally Posted by 1975300D

Tom, you mean this pic?

B C and J are connected to the triple nipple connector.

B and C are connected correctly.

J should be disconnected from where it is and reconnected to the line that presently has the drill or screwdriver bit inserted in it.

The line at point A is incorrect. I asked once before where is the other end of 'A' connected, and got no answer. Where is the other end of 'A' connected? I can't see it in the pic.

What I have called the 'triple nipple connector' (which has B and C attached) may actually have a fourth nipple, but I can't tell from the pic. That connector belongs on the firewall where 'A' is presently connected. I can't see but there must be another hidden nipple on there that can be inserted into the hole in the firewall where A is presently.

When you disconnect J and connect it properly, that will leave you with two unconnected nipples: 1) The nipple between D and E in your pic that goes to the WW nozzles on the hood; and 2) the now empty nipple where J was formerly attached. Connect those two nipples with a line.... You can probably use the line that is connected at A in your pic.

That connector should now be attached to the firewall with three lines coming off it. Starting at the bottom of the unit the lines should go to the following: 1) bottom line goes to the WW reservoir; 2) the line above this goes down between the brake servo and the fender toward the foot pump in the cabin; 3) the top line goes to the WW nozzles on the hood.

You are done.... At least with reconnecting this stuff. Again, as I said earlier, we don't know why someone connected these this way. Either they had no idea what the hell they were doing.... Or they DID know what they were doing and did this setup to compensate for some other unknown --- to us--- problem. That remains to be seen.

Good luck.

1975300D · #9 09-05-2011, 01:56 PM

Okay thanks Tom

So my problem at this point is that i need a 4-nipple connector which I don't have. Does this connector need to be special in any way, because the one there is white on one end, green on another with some bottle cap thing, and I'm wondering if some weird stuff goes on in there. Is it more than just a four-way splitter?

That 3-nipple connector has a forth connection point, but it is a snap on nipple that has tube A in the pic. The problem with that snap on connector is that it is phony! It is a sold piece of plastic with no hole!

tomscat1 · #10 09-05-2011, 02:02 PM

Ah. That is fine. That is the correct part. You do NOT need to replace it.

The solid nipple is the attachment point ... Attach it into the hole in the firewall where. 'A' is now. That piece has 3 hose connections, and one solid nipple to fasten it to the firewall.

Where is the other end of A connected to?

tomscat1 · #11 09-05-2011, 02:07 PM

Aha... I just reread your post ... You are doing fine.

So the hose A is attached to the firewall and to the solid nipple on the triple connector, correct?

LOL.

This is very simple:
Take hose A and attach it to the point between D and E on the line going to the WW nozzles. Attach the other end of line A to that bottle cap connector at the point where J was connected. Attach the bottle cap unit to the firewall using the solid nipple in the hole where A used to be.
You are done.

My, that was easy!

1975300D · #12 09-05-2011, 02:14 PM

So Tom, you mean there is no fluid coming out of point A? That hole is just to mount the connector? So that hose in my pic was just pushed in there for no reason?

tomscat1 · #13 09-05-2011, 02:17 PM

Quote:

Originally Posted by 1975300D

So Tom, you mean there is no fluid coming out of point A? That hole is just to mount the connector? So that hose in my pic was just pushed in there for no reason?

Precisely.

Wait... Let me rephrase that. It was pushed in there for a reason, apparently, but that reason appears to make no sense to me. Perhaps it made sense to whoever did it.....

In the meantime, is hose A long enough to make the connection from the nozzle line to the bottle cap unit?