Since the internal combustion engine is gone, I need to add a vacuum system to assist the brakes. I am working on this as I work on the controller board and the battery boxes. I could have gotten a complete kit from one of the EV parts suppliers or I could have pulled a vacuum pump from a junk GM car (early 80's). I found a pump on ebay from Jockmoonster for $98 + shipping so I went with that.
February 15. Here is the vacuum pump with a mount made of a piece of computer power supply box and some thick rubber washers from a broken suspension bolt:
Here it is mounted on the inside of the fender well:
February 21. I made a vacuum reservoir bracket by welding a wide strip of iron to a scrap of square tubing:
Here is the vacuum reservoir tube sitting in position for a test fit, not bolted in yet (I have to work on the battery frame):
I used 3" diameter PVC for the reservoir because that's what I had lying around. I got the end caps and some fittings at Home Depot.
February 28. I cemented the reservoir together with PVC cement, including a 1/2" MPT fitting in the top of one of the end caps. I screwed in a 1/2" brass fitting with a 3/8" barbed outlet. I scrounged some vacuum hose left over from our old minivan:
I cut and fit the vacuum hose into two plastic tees and attached an old vacuum gauge I had in a junk drawer. I put plenty of teflon tape on all the threaded connections. I hooked the pump up to a 12 volt battery and tested the system:
It works slowly, seems to have a leak somewhere. I put hose clamps on. In this view you can see that I primed and painted the reservoir bracket.
Hose clamps don't help. Do I need a check valve?
March 2. The vacuum pump lets air in the outlet when the pump is off so the system does not hold vacuum. I have emailed the vendor about the problem.
March 7. The vendor says send the pump back for exchange or refund. I asked him to exchange it for a Thomas pump if possible. If not, I'll get a refund.
March 23. The Thomas Pump arrived today.
April 2. Here is the pump, jerry-rigged for the first drive out of the garage:
The pump cycles on and off frequently, possibly due to a leak in the system.
April 3. I got a fitting that allows me to mount the vacuum switch on the brass tee. I also made a bracket to mount the vacuum switch on the inside fender wall:
Now the pump shuts off after achieving vacuum. No leaks.
May 2. Here is a picture of the final working system, with hose clamps and more securely mounted switch:
Batteries
Testing
Driving