Mighty Vacs, what are they good for?

[972500]

ive seen my bro using them to bleed breaks but that really is it. heck if thats all it good for then thats ok with me cause for 30 bucks not having to have somone around next time i do a brake job is worth it. but are there any cool tricks of the trade i can do with this thing
Thanks
Mark

 

[Charles (in GA)]

Many cars have vacuum diaphgrams used to do different things. A/C and heat systems use damper doors operated by vacuum, EGR valves are mostly vac operated, there are some vac check valves in most cars. Old (relatively speaking) cars have vacuum diaphgrams for the spark advance. These things are quite handy for testing and checking all of those diaphgrams.

My '67 Falcon has a vacuum only spark advance. You begin to suspect something is wrong when the performance (if there is such a thing on a 200cid Falcon 4 dr.) is sluggish. Get out the Mighty-Vac and test it, oops, leaks, head for the parts store.

Charles

 

[972500]

hold on so tell me this, i think my moms car has a vacum leak right. so is there somwhere specail i should hood this thing up to find it or tell if there is one. i know this sounds like i dont knwo waht im doin but i have a clue. just not up on the whole vacuum thing, i usually just deal replacing parts. honestly dont do taht much diagnostic stuff

 

[michaudracing]

hold on so tell me this, i think my moms car has a vacum leak right. so is there somwhere specail i should hood this thing up to find it or tell if there is one. i know this sounds like i dont knwo waht im doin but i have a clue. just not up on the whole vacuum thing, i usually just deal replacing parts. honestly dont do taht much diagnostic stuff

Yes, you could find the a leak this way. But newer cars may have a very complex arrangement with dozens of places to leak. It would help to know the circuit, so to speak, to isolate where to even check for the leak.

I have used the Mitivac to tune an adjustable vacuum advance on the ignition, to check cruise control pedal switches, etc. I keep finding uses for it.

-Steve

 

[Jared]

I have used mighty vacs to bleed clutchs, but i found that they are really slow on brakes. For finding a vacum leak just spray carb cleaner on the things that could be leaking and see if the engine speeds up, be careful because the stuff is pretty flamable. Sorry if this doesnt make sense, im bad at writing

Jared

 

[wilbilt]

hold on so tell me this, i think my moms car has a vacum leak right. so is there somwhere specail i should hood this thing up to find it or tell if there is one. i know this sounds like i dont knwo waht im doin but i have a clue. just not up on the whole vacuum thing, i usually just deal replacing parts. honestly dont do taht much diagnostic stuff

In that case, I'd say save the money on the Mity Vac and take the car to a pro.

They do lots of diagnostic "stuff". They can even bleed your "breaks" for you.

 

[972500]

no see takin it to a pro would defeat the purpose of it. i want to learn how to work on cars and i know what im doin as far as tearing down and building every part of a car so now im moving on the diagnostics. ya wanna start with my spelling problem? i know thats not the way to spell the "brakes" on a car but im LD and couldnt think of the right spelling at the time so sorry i apoligize, my bad. i know i got alot to learn so i'll just start playin around with it tommarow
Thanks for the tip
Mark

 

[eschoendorff]

ya wanna start with my spelling problem? i know thats not the way to spell the "brakes" on a car but im LD and couldnt think of the right spelling at the time so sorry i apoligize, my bad. i know i got alot to learn so i'll just start playin around with it tommarow
Thanks for the tip
Mark

Dude, no worries. don't sweat the typos....

 

[Charles (in GA)]

I have used mighty vacs to bleed clutchs, but i found that they are really slow on brakes. For finding a vacum leak just spray carb cleaner on the things that could be leaking and see if the engine speeds up, be careful because the stuff is pretty flamable. Sorry if this doesnt make sense, im bad at writing

Jared

I was largely referring to vacuum diaphgrams, check valves and dashpots, these are things you couldn't spray carb cleaner on and find a leak, certainly wouldn't want to do this under the dash in some inaccessable spot. Common leaks like split hoses are not that difficult to find, but to prove if something like an EGR valve is opening and closing, you need a Mighty-Vac to **** on it so you can see the valve move.

It doesn't get used often but when I need it, I have it and use it, very handy.

Charles

 

[wilbilt]

no see takin it to a pro would defeat the purpose of it. i want to learn how to work on cars and i know what im doin as far as tearing down and building every part of a car so now im moving on the diagnostics. ya wanna start with my spelling problem? i know thats not the way to spell the "brakes" on a car but im LD and couldnt think of the right spelling at the time so sorry i apoligize, my bad. i know i got alot to learn so i'll just start playin around with it tommarow
Thanks for the tip
Mark

Yeah, sorry...I was having an anger management moment.

Just be sure you know exactly what you are doing before you work on something important...like brakes...

The rest of us on the road will thank you.

 

[972500]

yea its cool. i know about the carb spray trick and ive done that and cant find the leak. so i'll look at it later today and see if i can figure it out
Thanks Mark

 

[Hurricane]

i used mine for the above purposes and to pull a vacuum on the ac in my car after i replaced the compressor rather than paying somebody to do it. theyre really only useful for checking diaphragms and such.

if you want to bleed brakes, **** out gear oil, transmission fluid (no more splash when you drop the pan), or empty overflow tanks etc than a fluid evacuator cant be beat. i built one out of a portable air tank i got from home depot for $25
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Harley-Davidson FLHR