$20 vacuum pump

[Shannow]

Been messing around, and today took a $12, 12V tyre pump, and converted it into a vacuum pump.



Pulls and holds 25" Hg, which isn't bad as we've only got 27" or thereabouts to play with (story for another day there).

The piston seal is angled the wrong way, and obviously I haven't run it on something with volume.

But will be useful in my refilling single use camping bottles, and maybe brake bleeding and the pile.

 

[michaelluscher]

How did you do that?

I need to get shop air one day, but could one of these things be strong enough to run a HF pneumatic brake bleeder?

I've got one of the standard issue GM included 12v units

 

[Shannow]

The cheapy I bought had a hole and reed valve in the head for the air inlet.

Cut a little piece of thick rubber that fitted over it, and made a copper plate to squeeze it down gasket like to effect a seal.

Then soldered a barb onto the copper plate, making sure that it had access to the hole in the rubber, through to the hole in the head. greased it up with lucas tacky grease.

Used the three original cylinder/head hold down screws to clamp plate/rubber/head/cylinder.

It's gone dark, but next weekend I'll see how quickly it can evacuate a 3 or 4 lb gas cylinder.

If it can do that, then I'm sure it's got some use.

And I'm more confident buying a $50 compressor to make a better one now that my $12 one works.

 

[Brad_C]

All the cheapo compressors I've bought to try that with have the reed valve in the piston, so a complete no-go from that perspective. You can put the entire pump in a container and have it evacuate the container through the discharge hose, but the commutator arcs get vicious as the pressure drops.

 

[Shannow]

Brad_C,
this is the one that's at Bunnings and Repco (same packaging, different printing).

There's a couple of Supercheap ones that have a hole in the head as well.

That sparking sounds gnarly. I've had a hankering to make a fusor at some stage.

 

[sciphi]

Originally Posted By: michaelluscher
How did you do that?

I need to get shop air one day, but could one of these things be strong enough to run a HF pneumatic brake bleeder?

I've got one of the standard issue GM included 12v units

I have that HF brake bleeder. That little compressor won't be able to run it. It consumes a LOT of air, enough where my 30 gallon 120v compressor was cycling about every few minutes to keep up. It might be able to bleed a clutch pedal or something that's close to the master cylinder if you're very patient.

 

[michaelluscher]

Originally Posted By: sciphi
Originally Posted By: michaelluscher
How did you do that?

I need to get shop air one day, but could one of these things be strong enough to run a HF pneumatic brake bleeder?

I've got one of the standard issue GM included 12v units

I have that HF brake bleeder. That little compressor won't be able to run it. It consumes a LOT of air, enough where my 30 gallon 120v compressor was cycling about every few minutes to keep up. It might be able to bleed a clutch pedal or something that's close to the master cylinder if you're very patient.


I see

How do you like the thing? I'm considering buying one because I'm finally gonna get me a compressor.

I'm studying sizes and horsepower

Would a 8 gallon 2 HP 125 PSI unit be able to run this?

I'm using it to replace brake fluid mainly, and suck out master cylinders and PSF reservoirs.

 

[JHZR2]

Dont those need air flowing through for cooling??

 

[Shannow]

Tested it today on a 3 or 4 lb propane cylinder and it pulled it down to 22" in a few minutes.

It got hot, but able to touch the cylinder so not THAT hot.

 

[HerrStig]

Originally Posted By: Shannow
Brad_C,
this is the one that's at Bunnings and Repco (same packaging, different printing).

There's a couple of Supercheap ones that have a hole in the head as well.

That sparking sounds gnarly. I've had a hankering to make a fusor at some stage.
I have fond memories of REPCO brake pads I used in several Volovs.

 

[Shannow]

Actually used it for something today, changed the fuel filter on my Nissan (diesel), and got sick of priming the thing witht the hand plunger.

$20 vacuum pump to the rescue, but when it sucked diesel, it could well have been a spray paint gun.

 

[Brad_C]

I'm surprised it didn't break something with a hydrolock. Obviously a rugged little unit.

 

[zzyzzx]

Originally Posted By: michaelluscher
Would a 8 gallon 2 HP 125 PSI unit be able to run this?

I'm using it to replace brake fluid mainly, and suck out master cylinders and PSF reservoirs.


I used a much smaller compressor and it worked. I also did have to start it my pumping the brakes. I was still able to bleed my brakes myself and it did a much better job than just using my MityVac.

 

[ryanschillinger]

I have he HF pneumatic brake bleeder and a 1.5hp compressor. It's definitely slow with my compressor, but it works.

 

[Shannow]

Lent the little thing to a bloke the other day who has a burnout car. They use the brakes to hold and control, but obviously they don't have vacuum to run the booster for 5 minutes of so.

He bought one specifically for his car for $800.

My little unit came close to getting the job done in his trials...he's going for an $80 compressor and a few fittings to see if he can get all the way there for $700 less for his son's car.