300td not shutting off...I've checked other threads...

[uberwasser]

That part needs to be replaced. The opening closer to the front of the car should be a nipple similar to the one next to it. With it wide open like that you're just leaking air back in to the system.

It is all one piece. You replace the entire hose from the vacuum pump to the brake booster.

[johnrf]

It was covered before, but with sealant and tape. (probably not the best) If there is supposed to be another nipple there, where does the hose go that connects to it? So the whole line, from vacuum pump to brake booster comes as one piece, with the valve already in the line?

[uberwasser]

That's correct, it's one piece, valve and all.

The routing of vacuum changes from year to year. Someone with your year and model may be able to help with a picture of their routing in the engine bay.

It looks like you want part # 123-430-74-29, you can get it on this site for $26.50.

[johnrf]

Thanks, I found the hose. I also found one on ebay, and it is missing the "second" nipple like mine. Could some of them have come like that? If the one port was covered up with sealant/tape, wouldn't that make the vacuum stronger coming from the one nipple that is there?

[uberwasser]

In this case the Genuine part is cheap enough that I'd just get the correct part.

There are some earlier cars that came with that main vacuum hose with just one nipple. My '79 is like that. However, the hose design is also different in how it connects to the vacuum pump. If you get the single nipple hose it may not bolt up properly and you'll be looking for the correct part again.

[Junkman]

I bought a main vac line for the SD off this site for not much money. See how inexpensive the rubber connectors are while you're buying. Also test the vacuum shut off valve itself by applying vacuum to it. A vac pump should shut the car off. No sense paying shipping twice.

You can plug the lines going to the passenger compartment until you have a chance to test and repair the leaks. There are likely some existing leaks in the other systems.

[johnrf]

I ordered the main vac line, it should be here in a few days. Right now, I have a vacuum line running from the fuel shut off valve, through the firewall and dangling by the hood release. When I need to shut off the car, I hook up the vac pump, give it two squeezes (about 10hg), and the car shuts off. I really think the problem was the metering valve on the main line, having 2 nipples should give me the vacuum I need.

[Junkman]

You may have a problem with your vac pump or brake booster. A friend of mine paid to have a vac pump replaced needlessly. The problem was no shut off. The shop measured 0 vac with the booster connected and everything else plugged. Car still won't shut off. The friend tried to beat me out of some cash so I give no guidance. Pay back.

You need to be through or you'll miss.

[littlehandegan]

I had this issue with a bad ignition tumbler

[chasinthesun]

Following the key tumbler as the no shut off problem is wise,I replaced a tumbler a few months ago and had connected the 2 vac lines running to the piece incorrectly ,the result was a no shut-off issue ,easy to check this off the list.To do this the right way youll need to pull the instrument cluster to gain some access to the lines otherwise your fighting a very tight area with only a few fingers to put the lines back on.Dont forget to reattach your oil line or the mess will be an interior floor of texas tea.

[johnrf]

Update...I ordered the main hose from this site, and a section of vacuum hose. I put the new hose on, hooked up the lines and it still wouldn't shut off. I then teed off the line going to the door locks, and the car now shuts off ! Im not really concerned with the door locks, but I now will check other systems to make sure they aren't leaking (car shuts off, but there is a sec or 2 delay...