1983 300DT, 205k miles.

Lost vacuum in last 100 feet before garage: brake booster, door locks, and car won't shut off without popping hood and hitting 'stop' lever.

In reading posts after a search, thought there was a slight chance of a blockage, took apart first length of pipe/hose coming off pump, it was clean, no sign of rust, oil or other blockages. Started car, put thumb over pipe, no vacuum at all.

So I'm thinking rebuilding the pump is in the cards. Part of me thinks I should buy the rocker arm too, but dang those are expensive.

So two questions. 1-How do you test if that has failed or not? 2-And, is failure of parts within the standard rebuild kit typically resulted in zero vacuum? It may well be that it has been decreasing over time, in particular door locks have been getting more persnickety lately.

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1983 300D- silver blue, tan leather, 205,000.
1975 Datsun 280Z. Stock, ready to restore.
1983 San Juan 23. Dry docked.

Removal of the pump and visual inspection is likely your best bet for determining the cause of your problem. The check valve where the line attaches to the pump is a frequent culprit. It can be removed with the pump on the engine. If I were going to rebuild the pump, I would also replace the aforementioned check valve, which is not part of the rebuild kit. The condition of the rocker arm can be easily determined when the pump is removed. Don't forget to obtain a new gasket, also not part of the kit.

thanks-

I'll be trying to figure out how to check that check valve with the pump still on tonight. Otherwise I guess I'll order one of those and the rebuild kit, and the gasket. Hopefully I'll have enough on hand to fix it once I take it off then.

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1983 300D- silver blue, tan leather, 205,000.
1975 Datsun 280Z. Stock, ready to restore.
1983 San Juan 23. Dry docked.

It's like most anything else mechanical. Unless you have x-ray vision there's just no way to know without tearing it apart for inspection. Fortunately in this case, it's pretty quick and easy to get the pump off.

There's just no other way.

Good luck,

Helpful info:
http://business.baylor.edu/Richard_Easley/autofaqs/Vacuum%20Pump/Rebuild_vac_pump.htm

To test the valves, use the "suck & blow" test. If you can blow air, the valve is opening, if you cannot suck air, the valve is closing. Otherwise the valve is toast
Vacuum pump draws air from the vacuum circuit.

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Tony from West Oz.
Fatmobile 3 84 300D 295kkm Silver grey/Blue int. 2 tank WVO - Recipient of TurboDesel engine.
Josephine '82 300D 390kkm White/Palamino int.
Elizabeth '81 280E, sporting a '79 300D engine.
Lucille '87 W124 300D non-turbo 6 cylinder OM603, Pearl Grey with light grey interior


Various parts cars including 280E, 230C & 300D in various states of disassembly.

This is an excellent tutorial. If your going to do a rebuild make the board. You will not regret. Use your new gasket as a template.

Danny

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1984 300SD Turbo Diesel 150,000 miles

OBK member #23

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