need help with brake servo connections

[glasers]

I have a 73 vw bus with no engine, due to the fact that I am turning it into an electric vehicle.

My question is this (I can't seem to figure it out from the manual)

I have a vacuum pump installed to run the vacuum assist brakes, and I am drawing a vacuum from the engine side of the Servo, but there is another air port at the front of the brake servo (shown in manual, but not indcating where it leads?), and I have no idea where it should connect, or what it connects to... I notice that when my vacuum is all set and I push the bakes, then this port sucks a vacuum, I'm almost thinking I just need to plug this air connection.

Does anyone know what I should do with this port?

Thanks

[Karl]

Do NOT plug it. The hose for it goes up in the body in the B pillar. It is there to supply clean air to the atmosphere side of the booster diaphragm. On a normal car, with the booster up high on the firewall, clean air comes from inside the car. On a bus, the booster is way down in the elements. So to keep water and dirt out of it, VW plumbed fresh air to the body.

If you cap it, then the diaphragm cannot move. Same as a vacuum advance unit, clean air is on the dist side.

[AhnwS71]

I just hooked up vacuum hose to the servo for the first time in who knows how long. Bus was idle for nearly 30 years. Before i did, there was a cap on the connection on the manifold. I pulled the cap off and ran new hose from there to the servo with a check valve along the way. Now when I press the brakes the engine stalls.

Is there a procedure for connecting the booster up for the first time other than just connecting hoses? like priming the system in some way?

thanks in advance for your help.
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'71 Westy

Sometimes you eat the bar, and sometimes the bar eats you. the Stranger

[TomWesty]