Vacumme pump

[spolij]

Been working on the climate control system especially the vacuum system. I have to keep the car running the whole time. Thinking about buying an electric vacuum pump.
Any comments or suggestions.
Thank you John

[Cadman-iac]

There's a variety of pumps available,  but probably the best ones are the ones used for evacuating an A/C system. They will give you a constant volume and will match what you can get from an engine.
The price can vary, depending upon where you get it, to the brand as well.
I have one made by I think it's Robinaire or something like that.  I have to pull it out and check the name.
I had one that was out of an old Sun diagnostic scope used to test exhaust emissions,  but it didn't have enough volume to really test anything that required more than a minimum of vacuum.
They also make a vacuum venturi unit for evacuation of A/C that works with compressed air,  but you need a good air compressor, and it's noisy, so if you  need to listen for a leak, that could be a problem.
I think a good A/C vacuum pump like the one I have is about $150 to $250 if you get a good name brand. But I believe Harbor Freight has some for less. Just remember that you get what you pay for when it comes to tools.
I hope that's what you wanted to know. If you don't do any A/C work, you may just be better off running the car.  The price of those pumps will pay for a lot of gas.

Rick

[spolij]

Hi Richard
I've seen the AC unit your talking about and you're right about using the compressor and all that noise being distracting. I'd rather listen to oldies on the iPod.
I was looking at a lot of the pumps on the Internet and they all talk about CFM I think that's cubic feet per minute, not sure. But the shop manual and the booklet I have from one of the members rates vacuum pressure in inches. I don't know how they correlate to each other. I know I need something that will at the very least match the 15 inches of vacuum from the engine. But it also must keep up with loss of vacuum doing tests.
I don't necessarily want to spend $200 on a machine that I might only use once. Especially if I can't fix the system I'll have to pay a mechanic to do it.
As for the gas versus running the car, I work on it maybe three days a week with the engine running 1 â€" 2 hours twice or more per day. So as far as the cost of fuel $3 plus a gallon I could easily burn up $200 a week.  LOL
thanks for the advice. I have to think about this more.
John

[Cadman-iac]

Hi John,  yes, CFM is cubic feet per minute, which refers to the amount of air that it will move. The measurement of vacuum in inches is referring to atmospheric pressure, or the lack thereof. Atmospheric pressure is normally 14.7 psi at sea level, or 29.92 -hg, inches of mercury.
For a better explanation, you can look it up on Wikipedia.
  I'm not sure about a vacuum pump,  but I do know that some parts stores will rent you tools to work on your car, like AutoZone for instance. You might want to look into that for a possible solution instead of buying one.
Although running the engine uses up some fuel, I don't think it's going to be near as much as you would think. The only problem with this is making sure that the exhaust is vented to the outside. You don't need to asphyxiate yourself.

Good luck on your repair.
Rick

[J. Gomez]

John,

If you need a cheap vacuum pump and you have an air compressor handy you can use one that is air operated. These uses an air compressor to create vacuum they are generally small volume 4.2 CFM @ 90psi and 28 hg in of mercury.

The draw back with these is you will need a fare compressor to keep up as it will be constantly running. You can find these at your local Harbor Freight for about $20 or so.

A second alternative is to get a small 12V like from eBay those advertise for car brake power booster, these will be a bit more $.

Good luck..!

[Cadman-iac]

John,

If you need a cheap vacuum pump and you have an air compressor handy you can use one that is air operated. These uses an air compressor to create vacuum they are generally small volume 4.2 CFM @ 90psi and 28 hg in of mercury.

The draw back with these is you will need a fare compressor to keep up as it will be constantly running. You can find these at your local Harbor Freight for about $20 or so.

Good luck..!

Those are the vacuum venturi type I had referred to earlier. They do a great job,  but they also require a good air compressor.  So not only do you have the noise from the compressor, you have the noise of the vacuum pump using the air to create the vacuum. It's like having an air leak at the end of your air hose. Very noisy, and you can't move it far enough away from the car to eliminate it,  unless you have 30 feet or more of hose to run back to your car from the pump.

[spolij]

By the way this is a 66 deville conv.
Like Rick was saying a compressor is too noisy especially if  your listening for leaks.
I was thinking about some thing like this.

https://www.toolots.com/vacuum-pump-xz-1b.html?cid=1469602941&gclid=EAIaIQobChMItYye5t2S6AIVA8DICh1P0wK4EAQYBiABEgK2SvD_BwE

This one says Ultimate Vacuum: 3 Pa so whats Pa?
https://www.toolots.com/2cfm-single-stage-vacuum-pump-1-4hp-xz-1c-110v-60hz.html?cid=1469602941&gclid=EAIaIQobChMItYye5t2S6AIVA8DICh1P0wK4EAQYCCABEgLXCvD_BwE

I can't equate 1.8 cfm to anything so i,m wondering if it would supply the 15" of vacuum needed and wouldn't collapse or harm something in the system like the master switch.
J Gomez   How do those specks relate to the 15" of vacuum from the intake manifold?

[spolij]

I'm thinking if i can find the right pump i would remove the fitting from the intake manifold and hook the pump up to the fitting. There by supplying vacuum to the entire system.
I looked up vacuum pressure on wikipedia lots of info i don't understand. It made me think i could use some kind of regulator to control the amount of vacuum.

["Cadillac Kid" Greg Surfas 15364]

John,
I believe you are over thinking this issue,  For control vacuum system checking I have never needed anything other than a hand operated vacuum pump.

https://www.summitracing.com/parts/lil-75000?rrec=true

you test one line, actuator, control valve at a time to isolate the exact problem.
Greg Surfas

[spolij]

Greg I usually do . lol

But if you use a hand pump and you disconnect a line, to do a vacuum test, do you have to re-pump to get the vacuum back?

["Cadillac Kid" Greg Surfas 15364]

You test each circuit individuAlly using the FSM diagrams.
Greg surfas

[spolij]

Greg   I understand about testing each circuit individually but my question is if you check one circuit do you have to re pump the vacuum in before you test the next circuit?

["Cadillac Kid" Greg Surfas 15364]

Yes. Hook up the line to be tested and then pump the pump to put that line into a vacuum
Greg surfas

[spolij]

Ok Thanks Greg

[fishnjim]

You can convert from Pa to psig.   Just a metric(SI) unit.

https://en.wikipedia.org/wiki/Pascal_(unit)

[spolij]

Jim   I went to that site but they said there was no such article on. Thanks anyway

[dadscad]

A/C evacuation pumps will pull 28-29 inches of vacuum. If you use one of those, put an adjustable vacuum break in line with a vacuum gauge downstream of the vacuum break so you can adjust the vacuum to the system to 15-20 inches of vacuum. That way you will have a more normal range of steady vacuum and won't have the possibility of damaging diaphragms or collapsing a hose.
I just recently went through my 63's vacuum system using a mityvac  hand pump.  I connected it to each individual  vacuum actuator and control switch to find the leaky culprits. Testing that way will show immediately what is good or bad. After replacing the leaky culprits, I hooked the hand pump to the main hose at the manifold to test the system only to find out the lines were also leaking. After replacing the lines I could draw a good vacuum with the hand pump to actuate the dampers from the main vacuum line at the manifold. Using a hand pump will give your hand a good work out but it is doable. HTH

[spolij]

David Thanks That's the answer i was looking for.

[dadscad]

You're welcome John, I hope you are successful repairing the vacuum system in your car. Getting to all the components can be a challenge but worth the effort once it is done and everything works like it should.