BUT,I swear this would make me rest easier 75K from now:
http://www.diyelectriccar.com/forums/showthread.php/mes-dea-gast-vacuum-pump-which-37410.html

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'84 300SD sold
124.128

Gotcha. What kind of pump do bigger trucks use for air brakes?

Sixto
87 300D

Just have to have strong legs.

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85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

An electric vac pump with a reservoir!

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

You might want to take a look at the alternator capacity before going to far down that path.

I thought big truck air brakes used air pressure, not vacuum. They will produce 150+ psi, but I suppose if you could tap into the suction side of the compressor and add a check valve to a reservoir, it would hold vacuum. It would make an awful hissing noise all the time, though

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Thanks,
Mark in NC

"Spark plugs?...We don't need no stinking spark plugs!"
1985 300SD "Der Silberne Schlitten" 420,000 mi


Wish these were diesel:
2003 Ford Club Wagon 130,000 mi

I considered making a catch-plate from a very-thin bit of sheet-metal. Basically, a perforated-ring, just like the paper pump-gasket. But with a raised section at the bottom, and maybe up the sides, to form a catch-cavity between the 'bell' of the vacuum-pump and the engine-block. It would just clear the cam-disc, and might be enough to catch some of the loose ball-bearings, though probably not lever-fragments. But it could also interfere with the oil-spray off the chain that lubes the pump.

I was a bit concerned about cam-wear, but there's not much I can do about right it now. The sheet that came with the new pump said that even 'minimal wear' would destroy the new pump. But what's minimal wear? It also said the cam-disc was NLA for some engines, without replacing the whole timer-unit!
I did see some visible rubbing/wear marks, but no gouging or any groove or ridge in the cam surface that I could catch with my fingernail.
Later, I thought about getting a cam-disc off the rough 240D I got the used pump from, or the clean '83 SD that was also there (Someone had already beat me to the pump from that one). But when I went back, both cars had been hauled away.

If I decide to try and retrofit something, I'm leaning towards a belt-drive pump. Perhaps I can rig a pump-mount on the block-off plate, as someone suggested. Then install a double waterpump pulley from a turbo 300D, and use the extra slot to drive the pump. (Of course that pulley may not help those that already have turbo models)
Another possibility is to position the vacuum-pump/pulley so it drives off the power-steering belt that already passes right-by the OE vacuum-pump.

Happy Motoring, Mark

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DrDKW

I have a spare vacuum pump from a RV that looks just like the Gast. I'll check and see what the p/n on mine is. It works as either a vacuum or pressure pump and is continuous duty. It does not draw that much current as I recall. It isn't that loud either. An added benefit is you always have compressed air to fill your tires and other uses.

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Make it out of ferrous steel and add a bunch of super strong magnets to it! If it can be designed to not interfere with lubrication it may save the engine when the pump decides to blow.

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

I think your're right! I must have been confused.

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked

Here's the driven end of a later 606 vacuum pump. No reciprocating parts in view.



I don't know if a 606 timer will slide onto a 603 (or 617) pump.

Sixto
87 300D

Sixto, is it easy to tell from the outside whether my pump is the newer design?

All the vane style pumps I've seen have a cast front cover vs the stamped brass cover in 603 pumps. The change occurred sometime in the 96-97 E300 range. 95 E300s have a reciprocating pump, 98-99 E300s have a rotary pump.

Sixto
87 300D

I thought that was a brass-colored steel cover, but my '96 has it.

Seems pretty extreme to change the timing device in order to run the updated pump. But what if the cam surface is bad? Seems like it's new timing device time anyway.

I don't know brass from wood The gold colored cover

I don't know if the vane style timer is even a bolt-on replacement. It might use a different spline.

Sixto
87 300D