Installing the Vacuum Pump

I installed the Gast vacuum pump and pressure tank next.


First, I installed rubber motor mounts underneath the Gast vacuum pump. Since I'm mounting this on uneven pieces of metal, I needed to add two 1/16" thick 1"dia. fender washers to the two feet on the front. The rubber feet serve two purposes: keep the motor vibration from rattling the chassis and raising the pump to clear the supporting angle iron. The rubber feet are 1" in diameter, 3/4" tall (rubber portion) with 1/4" threaded ends.


After installing the rubber feet, I put the pump in place and marked the holes on the supporting angle iron. After drilling 1/4" holes, I placed a 1" dia. fender washer (1/4" hole, 1/16" thick) on each of the holes to give the pump enough height to clear the vertical wall of the angle-iron on the right side of the picture.


Here's the Gast vacuum pump installed. I'll figure out the wiring diagram later.


The next step is to mount the vacuum chamber. I tried several locations but found that under the firewall rack was the most convenient. I drilled two 1/4" holes 21 1/2" and 23 3/8" from the passenger side end of the middle-rear horizontal angle-iron support for the batteries. This should place the tank between the control board supports that jut out at 17" and 27" from the passenger end.

Since these mounting bolts will be under the batteries, I countersunk the holes with a 3/4" countersink bit (see drill in background).


Here is the bracket that holds the vacuum chamber. These are 1/4" tapered flat-head bolts 5/8" long with two nylock nuts.


Before installing the vacuum chamber, make sure you align the nipples for all the hoses correctly. The top nipple goes to the brake chamber. The middle nipple (black) has a one-way valve to keep a vacuum in the chamber after the pump shuts off. The black one goes to the Gast pump. The pressure valve is attached to the bottom opening.


Here is the vacuum chamber installed under the firewall rack behind the Warp9 motor.


The next task is to get the vacuum line from the brake chamber down to the vacuum chamber. I like to reuse as much as possible, so I undid the clamp for the hose on the brake chamber and rotated the hose counterclockwise about 90 degrees. This puts the free end of the hose across the brake cylinder and down behind the firewall rack.

I also undid the clamps on the piece of hose farthest away from the brake cylinder and flipped it around so that the angles in the hose more closely matched the contours of the car. The grey module inline with the brake vacuum hoses is another one-way valve that keeps vacuum in the system.


With the original brake vacuum line snaked behind the firewall rack, I was able to attach the other end (with some minor bending) to the brass nipple on the vacuum chamber. I'll use the remaining vacuum hose that came with the Gast pump setup to attach the black nipple to the inlet on the Gast pump.

Whoosh, this has been a busy weekend. I'll see if I can get the engine wiring harness prepped before it ends.