My w123 300tdt only has about 14 punds of pressure,my mechanic removed the booster hose and measured the pressure,im trying to resolve an issue where car wont turn off at certain times,and the manual shutoff doesnt work at times either,can someone tell me if the pump is fixable or even how to R&R it,i havea good spare but dont know quite how to do it,thanks.

If the manual shut off lever doesn't engage, the you need to adjust the lever before you get into chasing vacuum gremlins. I am not sure on how to accomplish this, only that it can be adjusted.

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Dave
1983 300D Daily Driver

Ok thanks,maybe someone here can add to this.

If your vacuum pump has 14 lbs of pressure, no wonder you have problems.
Vacuum is measured in inches of mercury I think. Appropriate inches depends on your altitude. Somewhere between 18-21 inches is typical.

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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 can rebuild the pump. The kit is approx $40. I believe there are instructions online somewhere. Also be sure to look at the chech valve on top of the pump. It might be the problem.

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81 300D Turbo 190K sold
83 300sd 319K best $500 I ever spent-daily driverw/ 2 tank WVO set up

Hey, I can sympathize about the vacuum problems. I actually bought a rebuild kit for my '82 300D and in the process of trying to rebuild it, broke the old rocker arm inside, so I just put a new pump on. I have the rest of my old vacuum pump, and a perfectly good overhaul kit purchased from Autohauz.com that I'd be willing to let go for $50 plus shipping (thats for the old pump AND rebuild kit, $30+ just for the rebuild kit)... let me know.

Paul

This one is the rare type that has 2 hoses on it,an extra clear hose goes to air filter housing,is it possible for me to replace with another single hose type from another w123?
How do i remove the pump?
Many thanks to all

That's not a rare pump. It is standard on early 617's. It can be rebuilt without removing the whole pump from the engine. You don't even have to remove the radiator, just the shroud. Remove the outer cover, replace the diaphragm and check valves, reassemble. Should take less than 2 hrs.

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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

Ok i couldnt remove the entire pump because 2 of the bolts were so strippedi could not remove it.I replaced whole front of pump,the old one didnt have a cracked diaphragm but there was oil into the check valves and past the diaphragm,could this mean the actual arm was bad? now i still havent fixed my problem after having done all of that.
Help

Some people have used those external striped bolt head removers on Allen Head bolts. I do not know why they would work on them as they are supposed to be made for remove regular bolts with heads that have been rounded off.
But, some people have used them to remove Allen Heady type bolts.
I have seen them at Sears, Harbor Freight and Home Depot (made by Irwin). Some have more tools in their sets than others.

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84 300D, 82 Volvo 244Gl Diesel

Check on Diesel Giant for a tutorial... just to get started?

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"Those that turn their guns into plows shall serve and tarry for those who do not." Thomas Jefferson