will a vacuum pump make a tapping noise when it's close to worn out?

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1993 MB 300D 245K died.

I would think so. If the bearings were failing the lever arm would be bouncing around.

Trust your instincts and don't run the engine until replaced.

And when you get the old one out make sure you have all the bearing parts accounted for.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

The vacuum pump bearing rides on a cam that's part of the IP timing gadget. If the cam is worn or damaged, it can click. If you're sure this is where your noise originates, inspect both pump and cam.

If the one you have doesnt have a cage around the bearings make sure you replace it. Even with the cages they can still drop balls and ruin the engine.

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http://superturbodiesel.com/images/sig.04.10.jpg
1995 E420 Schwarz
1995 E300 Weiss
#1987 300D Sturmmachine
#1991 300D Nearly Perfect
#1994 E320 Cabriolet
#1995 E320 Touring
#1985 300D Sedan
OBK #42

Is the tapping coming from the vac pump cover area? (verify with mechanics stethoscope) Tapping on the om60x series can also be one or more faulty lifters...

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

oil pressure is good and I replaced the lifters and fuel injectors in hopes of getting rid of the tapping noise. mileage is well within the advertized amount. no smoke out the back and acceleration is normal for the w124. so I'm running out of options

__________________
1993 MB 300D 245K died.

good insurance to replace it now!

__________________
92 e300d2.5t
01 e320
05 cdi
85 chev c10

Indeed or all that hard work will be for naught. VP failure will kill your engine.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

I think you might be able to check it. If this Vacuum Pump has a Piston it is claimed that when it holds Vacuum that the Piston and the Parts like the Arm and Bearing that actuate the Piston are pulled away from the Timer Cam.

If that is so you should be able to detach the Main Vacuum Line at the Vacuum Pump and seal that Vacuum Pump inlet. When you start the Engine if it hold Vacuum like it is supposed to the Tapping will go away.
When you un-block the Vacuum Pump inlet then the Tapping should resume.

__________________
84 300D, 82 Volvo 244Gl Diesel

I went ahead and ordered a new pump, can anybody link me to the remove and replace procedures?

__________________
1993 MB 300D 245K died.

Have a 27mm on a long breaker bar handy to spin the engine.

You will need to remove the fan, belt, tensioner to get enough room.

On the VP, start backing off the bolts evenly a turn or 2. If you feel the vp getting pushed out, stop loosening the bolts and rotate the engine (clockwise!) until the pressure is relieved. Now you can safely back the bolts off.

Put the new VP in position, if it won't seat properly rotate the engine until it does. Carefully torque the pump bolts.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

I replaced the vac pump on my OM601 engine as soon as I got it. It still had the (operating fine) original cage-less vac pump at 260k miles....I still have it in a box.

__________________
-diesel is not just a fuel, its a way of life-
'15 GLK250 Bluetec 118k - mine - (OC-123,800)
'17 Metris(VITO!) - 37k - wifes (OC-41k)
'09 Sprinter 3500 Winnebago View - 62k (OC - 67k)
'13 ML350 Bluetec - 95k - dad's (OC-98k)
'01 SL500 - 103k(km) - dad's (OC-110,000km)
'16 E400 4matic Sedan - 148k - Brothers (OC-155k)

Setting the engine to TDC should put the pump drive cam at its lowest point.

Are you sure the noise isn't worn belt tensioner damper ends? Use a stick or long screwdriver to put pressure on the ends while the engine's idling to see if the noise goes away or at least changes. Mind the fan!

From within the US you can access the shop manual at startekinfo.com

Sixto
MB-less