It seems the supply of vacuum pump parts has dried up. I have a set of bearings to install but nothing else. Can I re-use the rubber gasket under the
valve and piston cover?. Can I reuse the pump to block gasket again and will it come off in one piece?

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1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

If you value your engine you will buy a new pump. Very small chance re-using the rubber diaphram or pump to head gasket will work.

Hi. Love to buy a new pump if I could find one. MB wants $575.00 in Canada.
Same price when landing from US. The car is worth what they want for a new pump. I get 14.5 " Hg on the pump so the piston seal is good. Just need a gasket set.

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1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

You can buy a new pump from the MB Classic Center for around $350 USD. The gasket alone is around $1.50. Gaskets are available on Ebay also.

Canadian price back in December 2015 was $413.

If you are speaking of your 1984 300SD turbo 126 you should have a piston type vacuum pump.

I was able to remove the front cover on mine (the one where the disc valves are located) and reuse the gasket with careful use of silicon sealant.
Note I also snapped off 2 of the little screws. I had to use a propane torch and penatrating Oil to get the rest of the screws out without snaping them off. I also used an Hand Impact wrench on the screw heads so that the heads would not strip.

The O-rings under the Valves can be replaced if you get ones that are fat enough in cross section. Note the directions that the valves are installed vefore removing them.

Since you don't have a new piston seal and O-ring you are likely better off leaving it along. Stretch has some pics of a vacuum pump take apart.

The Vacuum Pump to Engine Block Gasket you could make from a roll of gasket material.
You could reuse a good old gasket if you use dome sealant.

I found a place that has the vacuum pump for $300 but the piston end kit is $170. The new vacuum pump also comes with a new check valve. The valve used to be $28 by itself but the price on the valve alone has nearly doubled.

Kit part number for piston end is 0005861723

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84 300D, 82 Volvo 244Gl Diesel

If you're resealing and changing bearings this might help

More than you are likely to ever want to know about OM61X piston vacuum pumps

Another trick instead of paying for the expensive copper impregnated PTFE sealing ring for the piston pump repair kit is to buy the sealing kit for the earlier diaphragm pump and flip the piston seal round

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1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Well, I pulled the vacuum pump today, replaced the two bearings using a small shop press. Thanks to Stretch for his great write-up the job went with out any problems. I rigged up a 2 x 4 with some bolts I had and made a simple gadget to compress the spring. The tin is to protect the roller from the turning 5/8" bolt threaded into the wood. One of the 1/4" bolts is sloppy in it's hole to get away from precision drilling. It worked great. I could not do this job so easy. One of the old bearings was smooth the other was very rough and catchy. Got to this just in time.
The old gaskets were in good shape, slapped on a rub of grease and reassembled. Had 15Hg before and also after reassembly. I removed the rad hose, the PS belt and the fan and cowling. Lots of room to get to the bottom bolts.
When I see the design of this pump I have to ask what in hell were the engineers thinking to design a thing like this to pump a vacuum. A simple rotating vane is so simple and easy to rebuild. If I could find vane pump that turned clockwise I would machine a mount and bolt to the circular bolt pattern of the MB pump. Because we have a chain cam drive and every one else has a gear train rotation direction becomes a problem.
I can hear some one saying the pump can't be that bad, after all it ran for four hundred thousand miles. I agree.

Attached Thumbnails

     

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1984 300SD turbo 126
"My true love"

God made me an atheist and who am I to question His wisdom

The bearings are the only danger to the engine, which you changed. The other parts only risk not getting vacuum. I think some parts are common to VW diesel mechanical vac pumps, as I recall seeing the internal check valves in those kits on ebay.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans

A worn timer bushing can cause a vacuum pump failure.

What in particular causes vacuum pump failure?

2 Vacuum Pumps destroyed timer Bushing Identified as the problem
http://www.mbca.org/forum/2013-12-29/why-are-these-vacuum-pumps-being-destroyed

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84 300D, 82 Volvo 244Gl Diesel