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Ole Guy
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Power Vacuum Bleeder: Simple, Homemade, Free



What you need:[/b]

  • Strong Vacuum source (car engine), maybe a house hold vacuum
  • Tall clear jar with lid
  • 25 feet of clear plastic line (1/4 line comes in 25 ft rolls in the plumbing section for a few dollars), must fit on the bleeder nipple snuggly
  • An assistant will be useful
  • Vacuum adapters if needed
  • Brake fluid


Jar setup: [/b]The jar will need two snug holes drilled for the plastic line. Insert the incoming line to the bottom of the jar and the out going about one inch. Place the jar between the bleeder and the engine vacuum. The suction flow is from the bleeder to the jar, then from the jar to the engine vacuum. The jar captures the waste fluid preventing it from flowing to the engine. Use common sense and do not allow the jar to fill. Burning brake fluid in your car’s engine may damage the catalytic converter! If that bothers you, use something else that really sucks. The jar ought to be larger than the quantity of brake fluid container. Position the jar so it cannot tip over or it might suck fluid into the engine. I used a tall coffee jar with a plastic lid.



What Happens: [/b]This suction-bleeder uses engine vacuum and the pull is very strong – maybe too strong. When the bleeder is open, you will only see streaming cavitations that appear to be air bubbles -- any trapped air blends in. You are looking for a color change of old and new fluid. First, a stream of milky brown that turns to a clean milky white in seconds. It’s that fast! This is where your assistant comes in handy pouring fluid into the master cylinder. Be careful not to suck the master cylinder into the jar.



Setup and bleeding:[/b]

  • Connect your lines. The incoming line connects to the bleeder (the one that goes to the bottom of the jar). The outgoing line (suction) connects to the engine vacuum – just pick a good vacuum source.
  • Position the jar so it cannot tip
  • Remove the master cylinder cap
  • Top off the master cylinder with new brake fluid to the very top – it goes down quick
  • Position your assistant at the master cylinder to pour fluid as it is pulled down
  • Start your engine
  • Crack open the first bleeder starting with the most distant one until you observe cavitations
    • Leave open until the clean fluid appears – it should appear milky white in seconds
    • You might see bubbles at the bottom of the jar; I don’t remember having time to look.
  • Move to the remaining bleeders
  • Test brake action -- it should be improved after the first round
  • Optional, dump out the dirty fluid after the first round
  • Circle around the bleeders again until they brakes are solid
  • If the master cylinder goes dry, start again you have just added more air
  • If there is no pressure or they are spongy, start troubleshooting
    • Work the brake pedal to make sure the vent hole is open on the master cylinder. It must be open to pull fluid. You might be able to see it on some master cylinders and fluid will squirt out with the cap open. Watch your eyes! It will shoot fluid out some distance!




Bleeding brakes is simple unless you are fighting trapped air. In theory, the trapped air will eventfully make its way up to the reservoir in the master cylinder and escape through the vent hole -- known as a well-designed system. Some systems are, most are not. Some mechanics let the newly filled brake system sit over night so the bubbles float out. If the simplest method of pumping and opening the banjo nipple fails, it is because it moves too little fluid, too slow. The trapped air moves a little, and then floats back. You end up with no pedal pressure or spongy action. After a few attempts of pump-and-release, you will know if you need more. The idea is to move trapped air forward faster than it can move backwards. If the entire brake system were clear as glass, you could see where the trapped air was and position the bike so it flows upward and out the vent. This home made suckermoves all the fluid and air between the master cylinder and the nipple in just seconds. If there is still trapped air, it is trapped in an out-of-the-way reservoir or metering devise with its own bleeder. This could be a metering valve between front and rear brake or antilock devises. Theolder Yamaha Ventures hada metering valve with a bleeder under the seat somewhere. Trace the lines to locate these devises and bleed them if there is a nipple. If there is any trapped air, this suckerwill surely suck it out in just seconds the first time. It’s never failed me – ever.



This method has never let me down on any vehicle, even equipped with complicated anti-lock brakes and I never had to turn my bike upside down yet! If you cannot get the air out and you are sure you have found all the bleeders, then you probably have a more serious problem, such as clogged or pinched line, leaking seals, etc. Power suction leaves no bubble behind. Its one of the best homemade devises I have made fornothing.



A friend of mine once told me he used his engine vacuum to pull a vacuum on his AC. He rigged up his AC gauges to the engine vacuum. He then drove a distance to his father’s home where they added the Freon. I think this is where I got the idea after seeing the prices of expensive vacuum pullers. Being broke is the genius of many ideas.
 

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Where there is a will, there is a way!
I have an ac vacume pump, will try that on my mushy front brakes. Shimmy.:walker:
 

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Ole Guy
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Discussion Starter #3
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I have never used an AC vacuum pump. Will it pull a large volume fast? That is the trick here. The first time I did this, it took me a few minutes to figure out where the endless bubbles were coming from -- cavitation. It worked better than expected. Kind of like the first time I used an impact wrench the first time -- were did the nut go? Make sure the fluid flow is swift. PS, I don't have spongy brakes no more.
 

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i bled the heck out of my front brake on my 86 1200 and the lever comes with in 1/2" from the heated grip - all sponge - so ill be assembling a bottle as proscribed - i did see the metal brake line goes down to the lower triple tree then bsck up 2-3 " to a mounting point so air can hide in that loop-
question, why wouldnt the vaccuum evacuate as much fluid as air in this process ? imy assistant doesnt need to pump the lever , just keep it filled, as the fluid runs down the little vent hole ? its not plugged, the 86 has an anti splash tin on top of the hole so it doesnt eject fluid from the tank as the levers being pumped - sure tired of 3+" of lever movement lol
 

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25 feet of clear plastic line

Route the line up over a tree limb or rafter if you have a garage, then back down to the bottle.
If you have a shop vac use that instead of your wife's vacuum cleaner.

Take precautions to keep brake fluid off paint.

I've used this on the clutch, and single front brake. I think there is a tip I'm forgetting on the rear/front interconnected system.
 

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sweet- i was going to adapt my wetordry to do the job i was thinking--and routing the line up over the bike several feet allows for only air to get pulled out of the system -i tested the master with a pair of needle noses and the lever is as hard as a rock NOW when the line is carefully clamped-- thanks
 

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my shopvac didnt work
 

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it just occurred to me i can identify where the air is hiding by clamping the line - it may be in the disc cylinder itself , if i clamp it just upstream of the cylinder and have a good lever
 

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Some one on the board wrote up a note about using the spray bottle pump. I tried that set up and it seemed to work some what, but i still had a spongy front break. A trick that I had used for my old BMW worked on the Wing also. Pump up the lever and tie it in place. Let it set over night and the bubbles will start to work their way out. You may even have to do it a couple of times, but that is the way I got mine to firm up.
 

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FWIW i clamped the hose 2" from the wheel cylinder and the lever locked up -zero air in the line, its all in the cylinder -i got to wonder whats going on here -will a 1986 aspencade cylinder (9mm disc width) fit on this interstate? im thinking thats whats on here - the cylinders are protruding half of their travel from the caliper -with new pads- it looks like the PO put 'Cade calipers on it, my discs are 4mm wide
 

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oops another thing just struck me on me noggin - with the bleeder at the virtual bottom of the caliper how can any air be expected to be expelled without an arguement ?-im now thinking (uhoh here we go) that the caliper needs to be situated "bleeder up" during a otherwise normal bleeding session with a piece of 4-5MM flat stock for a spacer betwixt the pads and itll all be good -hope
 

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when you used the wrap tie did you have the resovior cap in place and the system was all tight?
 

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Junior Grue
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I'm seeing two problems here Kevin.:shock:

First one is that someone replaced the calliper with the wrong one as the bleeder should be at the top.

Second one is that you need new brake lines as once you clamp them off you've destroyed the integrity of the steel braiding and/or the bonding of the inner lining.

Personally I'd be parking the bike until I got the correct calliper and replaced any lines that have been clamped.
 

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You can move the bleeder. There is a set screw on the other end (Top on your bike it sounds like) of caliper. Remove it and swap it with the bleeder valve. Use the set screw were your leader is now. To tie the handle off over night, cut a 1" wide binder from an old bike tube and use that over the bar-end.

Don't clamp the brake lines it's not good form.

Steve
 

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Junior Grue
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SuperSkypilot wrote:
You can move the bleeder. There is a set screw on the other end (Top on your bike it sounds like) of caliper. Remove it and swap it with the bleeder valve. Use the set screw were your leader is now.

Steve
That won't work Steve.
I just check an old calliper and the bleeder valve is 9mm and the set screw is 11mm.
 

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#9 Man wrote:
when you used the wrap tie did you have the resovior cap in place and the system was all tight?
Yes, cap on and the system closed. The constant pressure helps force out and bring the bubbles to the top
 

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Thanks, but I can barely manage a 25' extension cord without problems let alone 25' of oil filled hose. I will stick with my mighty vac. Easy to control and many other uses.
 

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Ole Guy
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Discussion Starter #20
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Air rises in solution, so the bleeders must be located at the top or the high spots. Since the bleeder is at the bottom in this case, you must remove the caliper and position the bleeder at the top as you suggested. Air can be sucked or pushed through the line because the passage is narrow and the air bubbles can be drawn through faster than they can rise or move backwards. If the passage hits wide spots, high spots, other devises with wide cavities, this can be a problem. It was on the rear brake/front brake on my GL1200.

Clamping the brake line off to troubleshoot was a brilliant idea. Too bad it compromises the integrity of the line. Feeling lucky may not be enough to keep you safe on future rides. Tying down the pedal or level over night does work. It’s kind of like magic. On my 1985 Goldwing I was not able to draw all the air through on the back brake that shares one front caliper. I tied it down three nights in row. For this to work you must be able to squeeze it down with a fair amount of resistance at the start. After bleeding, my rear brake would lock the rear tire at maximum pedal throw. After the first night the throw was reduced to 2/3s travel. After the second night it was reduced to about ½ travel. After the third night there was no more improvement. I was able to wedge the pedal down with a piece of wood making it easy to do. My front brake was okay, but I tied it down anyway and there was a bit of improvement. I was curious where the air went. After scouring the internet I discovered new brake fluid is considered to be dehydrated and has a large capacity to absorb air. Under pressure it will absorb air including moisture. Simply said it acts like a sponge and can absorb a fair amount of air. At some point the fluid becomes saturated and usually turns brown, this is by design to neutralize the damage moisture can cause internally. Not all new brake fluid is equal in being dehydrated as manufacturing methods, handling, and age have an impact. Hope this helps.
 
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