Manually operated vacuum brake bleeder with at least 30 hg/1 bar of vacuum?

[vavavroom]

Let me preface my inquiry by saying I don't need this sucker for brake bleeding but for off-label use. No, I'm not getting into the five Ws. We'd be here for three days with a 10-page thread. I don't want that and neither do any of you.

Pressure gauges on vacuum brake bleeders commonly go up to 30 Hg but that doesn't mean anything. If a manually operated brake bleeder is not an option, can you recommend a different kind of manually operated vacuum pump? I don't feel like building my own with a syringe and a non-return valve or something nutty like that.

 

[SHOZ]

30" Hg is pretty hard to achieve and manually even harder. My cheap harbor Freight one can get up to about 20".

 

[tcp71]

MV8000 by mityvac goes to 25Hg.

 

[Trav]

Let me preface my inquiry by saying I don't need this sucker for brake bleeding but for off-label use. No, I'm not getting into the five Ws. We'd be here for three days with a 10-page thread. I don't want that and neither do any of you.

Pressure gauges on vacuum brake bleeders commonly go up to 30 Hg but that doesn't mean anything. If a manually operated brake bleeder is not an option, can you recommend a different kind of manually operated vacuum pump? I don't feel like building my own with a syringe and a non-return valve or something nutty like that.

Depending on location 30Hg may not be possible.

 

[vavavroom]

I probably should have said I'd like to get as close to 29 Hg as possible. Looks like a manually operated pump is out. 25-26 Hg may be enough but I would have to test it.

 

[Trav]

I can get about 26-27 with a Mityvac MV8500.

 

[vavavroom]

Depending on location 30Hg may not be possible.

View attachment 241083

Thanks. That chart is most useful.

 

[Rand]

Thanks. That chart is most useful.

What is your elevation?

 

[ripcord]

I don't think DIY space suit testing is really such a great idea.

 

[vavavroom]

I can get about 26-27 with a Mityvac MV8500.

Thanks for the figures that are based on your experience. I am inclined to try that and see if it's sufficient before going for a motorized pump.

 

[vavavroom]

What is your elevation?

No more than 80 feet. Not much of an obstacle.

 

[eljefino]

You'd need a hyperbaric chamber surrounding your project to get greater than 30 Hg of vacuum.

 

[redbone3]

My career was as a calibration technician. In Reno the average pressure is around 25" of Hg. Customers would ask why their vacuum gauges were not calibrated from 35" to 30". You can't remove what isn't there.

 

[vavavroom]

You'd need a hyperbaric chamber surrounding your project to get greater than 30 Hg of vacuum.

I rounded. That's why I clarified: "A close to 29 Hg as possible. I believe a perfect vacuum is just below 30 Hg, 29.9xxxx or whatever.

 

[D60]

Depending on location 30Hg may not be possible.

View attachment 241083

My first thought, too. When I'm pulling down a/c systems I can never get what they do in the vids. Then I realize my shop is ~6800'

 

[Cruisin'n5thgear]

Standard sea level is considered 29.92 inches FYI.