[Vwdiesel] My vacuum pump isn't vaccing

[Doyt W. Echelberger]

Anybody know how to revive the vacuum pump? The one on my 84 Rabbit D isn't 
pulling enough to help the brake booster, and I have to stand on the pedal 
so hard it is unbelievable.

Here is all I have on the subject....stuff from Loren, of course. Reading 
Loren's post makes me wonder if it isn't the brake booster also. I pulled a 
vacuum on the booster and it wasn't very reassuring.
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Date: Sun, 18 May 2003 22:53:58 EDT

 > Does anyone know the part number for the diaphragm kit for the later vacuum
 > pumps? I have an 85 Golf with a vacuum pump that looks different than my
two
 > 81 Caddy's. The 85 doesn't have the large round area where the diaphragm
goes.
 > Looking down from top the area where I expect the diaphragm would be looks
 > like it is shaped more like a home plate in baseball or sort of pentagonal.
 > Anyway, it isn't round.
Isn't it more or less a barrel shape with an odd shaped top? All cast iron
and steel instead of aluminum? Those don't have diaphragms, or valves.
They're a rotary pump, like a smog pump or the "lift" pump in the VE pump.
If it's not pulling a strong vacuum, first look for leaks or a bad brake
booster.
If the pump's worn, like mine was, you'll need to face the lid and grind down
the body a bit to match up with the rotor. The rotor could most likely need
faced lightly as well.
Loren
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I remember taking a pump apart, and it sort of exploded in the final 
disassembly, from the pressure of internal springs. It just popped apart. 
Sounds like something a rotary pump would do.

So, I am asking if anybody can offer any BTDT to improve my chances of 
getting it to work better. Summary....this is a vacuum pump on a 1984 
Rabbit n.a. Diesel. Is it a rotary pump?

And, I guess I better ask how difficult is it to replace the brake booster.


Doyt Echelberger