Those negative pressure hand operated brake bleeder kits are a real pain to use especially if you are doing a full system bleed. I am not sold on the pressure bleeders and I do not always have another person on hand to pump while I open/close the bleeder.
Anyone ever build an electric vacuum pump to bleed brake/clutch systems? I cannot seem to find on on the market and thought how hard and expensive could it be to build one?
As long as you keep fluid available, the pressure bleeders work great. I used one at the dealership all the time, whether it was a "flush" or replacing a caliper or wheel cylinder. The pressure bleeders are great when it's you and only you.
But to answer your questions, nope and don't know.
speedbleeders work awesome! These make it a one man job also.
That is all I use.
Rob
the have them on the market, I think alot of people on here have the motive pressure bleeders.
I have a refrigerator motor under my bench that sometimes pulls vacuum duty. Usually for AC stuff and bench testing vacuum stuff on a car.
For the amount of vacuum needed to bleed brakes, a dustbuster might suffice.
I'm actually looking at my dead battery jumper box that has a inflator pump on it It works when plugged in to 12V or 110 and with a little plumbing it should pull a decent vacuum.
Once you have your fluid catch container all you need is a source of vacuum!
Cool!!! found this for a vacuum source:
http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&productId=202078693&langId=-1&catalogId=10053&PID=500871&cm_mmc=CJ--500871--10368321&cpncode=21-97578245-2&AID=10368321&cj=true&srccode=cii_9324560&locStoreNum=901
Real grassroots vacuum learned from a WW2 tank mechanic is to use an old propane cannister, put about 1/3 cup of water in it and heat until it steams. Once you have steam coming out, just close the valve and when cooled, you have vacuum.
In a real pinch you could start the car and hook a line to the manifold.
Bruce
kabel wrote: I am not sold on the pressure bleeders
Any particular reason?
Fundamentally, the reason bleeding works is that you're creating a pressure differential across the fluid. Whether that's below atmospheric at the nipple or above at the reservoir, it should have pretty much the same effect.
I haven't used them, but I've always been a little worried about vacuum type bleeders drawing air around the nipple's threads; this is not an issue with pressure bleeders.
I am curious: While I like the idea of pressure bleeders somewhat better, it'd be nice not to muck about with plumbing a pressure source to the reservoir, and the range of nipple sizes is simpler to adapt to than the array of reservoir caps...
I guess I'm not 100% sold on the pressure bleeder systems. most consumer level products do not isolate the pressurized air from the fluid. Hypothetically pressurizing the air inside the container with the fluid results in air and moisture forced into the fluid. perhaps that amount is so minor it makes no difference.
I have also been eyeing the Phoenix Systems V-12, an interesting method to pushes fluid through the system from the caliper end but again this is a hand pumping system.
Well, if you are patient, you can just leave the bleeders open and let it drip out. Should work for fluid replacement, probably not so got at getting air out (bubbles will have time to hid in high spots).
I'll be doing the gravity feed method to start with in this case (because the system is essentially empty after replacing the master, rebuilding the calipers and installing new ss lines). But know I will need to bleed using one of the common methods to ensure all the air is out.
If you get over your hypothetical objections to pressure bleeders you can borrow mine 
Its a Motive and I have the adapter for a BMW master cylinder.
It's by far the fastest and easiest way to do a brake fluid flush. When you're working by yourself its about the only way as well. If there isn't a ton of air in the system a gravity bleed will work eventually but it didn't work so well when I replaced the ABS actuator on my old F-Body. Plus its a PITA to babysit the reservior to make sure it didnt go dry.
Speaking of pressure bleeders, are there any that use an existing compressor as a source of pressure? I'm not convinced that I do need another pressure tank in the garage...
I built my own vacuum bleeder. I had a small diaphragm type compressor from an air brush kit i bought at a yard sale. It had two ports on vacuum one for pressure even has a regulator on the vacuum side. I used motorcycle polyurethane gas line and an empty Paul Newman's marinara jar. In the jar lid i poked two holes smaller then the hose but big enough to slide the hose in. One hose goes in about an inch this hose goes to the vacuum port the other hose got pulled all the way to the bottom of the jar this one goes to the bleeder.
Works great.
Air pump for fish tank? Same type pump?
I don't think a fish tank pump would have enough constant psi (torque if you will), but I'm just guessing there. Tim, I've see discussions on people using a tire as their compression source, would last longer than the pressure tank that comes with most systems.
In reply to kabel:
Hey Kevin I have one of these Shuco aspirator pumps that I use for brake bleeding:
I bought if off of ebay for like $70. You're more than welcome to borrow it sometime, it works great.
BoxheadTim wrote: Speaking of pressure bleeders, are there any that use an existing compressor as a source of pressure? I'm not convinced that I do need another pressure tank in the garage...
Yes, just add a regulator to get the pressure down to 20 psi or less. One downside is that compressed air tends to have a high moisture content, which would add to the OP's fears.
I've rarely been able to get vacuum bleeding to work for me. Usually there is too much leakage past the bleeder screw threads.
Speed-bleeders FTW. I've seen them on the shelf for years, but now wish I'd believed years ago.
Ian F wrote:BoxheadTim wrote: Speaking of pressure bleeders, are there any that use an existing compressor as a source of pressure? I'm not convinced that I do need another pressure tank in the garage...Yes, just add a regulator to get the pressure down to 20 psi or less. One downside is that compressed air tends to have a high moisture content, which would add to the OP's fears.
Well, that would give me an incentive to finally hook up the water separator I have cluttering up the garage at the moment. Plus, living on the edge of the high desert out here, bleeding brakes in Summer shouldn't introduce that much moisture.
Ian F wrote: Speed-bleeders FTW. I've seen them on the shelf for years, but now wish I'd believed years ago.
Guess I need to look at those then, at least for our long termers.
BoxheadTim wrote: Guess I need to look at those then, at least for our long termers.
I plan to put them on everything that needs periodic fluid flushes. I can't imagine why anyone wouldn't have them on a track car where you're doing flushes after each session.
The first time I used them it was an epiphany - why didn't I buy these things years ago???
In reply to Ian F:
Even more than with the vacuum bleeders, it seems like speed-bleeders would run the risk of sucking in air around the threads... I have it it my head that they use a sealant of some kind, or a wrap of teflon tape, or... ?
It just concerns me that on the upstroke of the pedal, the system's going to be running a vacuum, and if those threads aren't sealed, I can't see why it would rather pull fluid out of the reservoir than pull air past the threads.
Gravity works in favor of pulling fluid from the reservoir, but viscosity votes in favor of sucking air past the threads. And correct me if I'm wrong, with the master cylinder well down in its stroke due to purging fluid out the bleeder, isn't there going to be a period of pedal uptravel where the system would like to be replacing the lost volume, but the master cylinder hasn't unshrouded the reservoir port yet?
New speed bleeders have a thread sealant pre-applied. If the female threads for the bleeder are loose enough that the don't seal well, then bleeding with a vacuum set-up won't work either. But it seems the speed bleeders are more reliable for quick bleeds when the desire it so get a bit of air out or to change fluid it out.
Where I found them not to work as well was when there is a lot of air in the lines as it seems pedal-pumped air pressure isn't enough to overcome the bleeder's check valve spring. In that case, I've eitehr gravity bled most of the air out, or I removed the bleeder entirely and mity-vac'd out most of the air the messy way.
mblomell, THAT is exactly what I was talking about!
I've used vacuum bleeders, pressure bleeders, gravity bleeding... even a long wooden rod to pump the pedal with while I worked the bleeder with the other hand...
NONE have seemed anywhere near as simple or effective as two dudes yelling at each other in a garage.
Seriously, after everything my favorite method is as follows:
One man in car, one man starting at furthest line.
Outside yells "PUMP" while pouring fluid into bottle, getting a wrench on the bleeder then running some hose from bleeder to fluid inside the bottle.
Inside yells "PUMPING" then pumps the brakes 4-5 times steadily Inside then holds the pedal and yells "HOLD"
Outside cracks the bleeder and watches bubbles.
Inside waits for the pedal to hit the floor, then yells "FLOOR", while continuing to hold the pedal down.
Outside closes valve and yells "PUMP", and the cycle repeats, then onto next wheel.
It feels a bit foolish yelling back and forth constantly at first, but keeping track of where each other are and not having to guess makes things thoughtless and a lot quicker. We can bring a car in, get it on jack stands, bleed breaks and get it back out in just over 5 minutes.
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