I am troubleshooting a no shut-off issue and have found that there is no vacuum present from the nipple closest to the brake booster in the main line from the vacuum pump to the booster. Since the shut off is fed from this nipple I am assuming this is my issue. Is it possible to replace just the valve piece or would I need to replace the whole line? Does anyone know why this piece might have failed. I am getting about 15 inches on the front nipple at idle.
Thanks!

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1985 Euro 300TD Turbo

Sounds like something is plugging the line. Why else would you not have vacuum there if you have it upstream?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

I would think you can remove the check valve and test again.

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83 SD

84 CD

Yes, but be careful, that line can be fragile. Might want to try heating things up with a hair dryer before removal

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13

You'll never get that check valve out and be able to put it back in. That line is hard plastic, and one you've molded it to something you'll never get it to go back to the original shape if you try to remove it. If something is wrong with the check valve that is preventing vac to get through, I would think that you would have no vac at the booster either, and then you'd have brake problems. I'm guess the nipple it cracked or plugged. Inspect the nipple carefully. Maybe poke a small nail into the nipple to see if something it lodge inside. Then I'd try removing the whole line and gently blow some air through the nipple to see if it dislodges anything.

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I didn't check vacuum at the booster, but the brakes are very stiff leading me to believe there is little to no assist. I am thinking there is something wrong in the check valve and I also suspected it would be difficult to remove the valve from the line. Thanks for the help.

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1985 Euro 300TD Turbo

Try removing the line from the booster, and plug in a mity vac. Then start the car and see what vac reading you get. If you aren't getting about 20" then something is wrong. Also 15" at the good nipple is getting to be pretty low. You generally want at least 18" or more.

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I think we have similar vacuum lines. My main vacuum line has two nipples. One managed to get plugged. I solved the problem by manually running a drill bit down the nipple. Don't remember the size, but you do not want to make the hole bigger.

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Charles
1983 300D, bought new, 215k+ miles, donated to Purple Hearts veterans charity but I have parts for sale: http://www.peachparts.com/shopforum/showthread.php?t=296386

It has been mentioned previously; I am in favor of checking the Vacuum Pump first. Autopart stores used to sell a rubber cone shaped adapter that you could use to check the larger Vacuum Lines.
If it turns out the Vacuum Pump is not putting out enough unscrew the fitting that the Main Vacuum Line attaches to. It is also a Check Valve.

Inspect it to see if the parts inside are still intact. If not that could be the issue. If that check valve is no good it is a $50+ item to replace.

If it is just mucked up with crud spray it out with WD40 to clean it; that worked for me when I lost vacuum.
Post #5 has a pic of the Vacuum Pump Check Valve
http://www.peachparts.com/shopforum/showthread.php?t=289316

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84 300D, 82 Volvo 244Gl Diesel