Brake bleed/flush without vacuum?

[JimGregory]

I just went through the whole process by just pumping pedals and levers.
Seemed to work fine.
What is the need for vacuum equipment about? Is my bike about to self destruct?

 

[paulcb]

Assuming this is a serious question, vacuum just makes it easier and (much) quicker for one person to successfully bleed/flush the system. Also helps with those systems that are difficult to bleed.

 

[BakerBoy]

Vacuum equipment is not needed, but it can speed up the process. I too have always used the lever pump method, synchronizing each lever action with an opening then closing of the bleed nipple. As long as the reservoir is kept filled with fluid, no air is pulled into the system.

One of the issues of any other technique is that the threads at the bleed nipple leak in air--many folks wrap the nipple threads with Teflon tape to reduce that, or like me we close the nipple at the end of every lever stroke so that air isn't pulled back in through those threads.

There is no right way or wrong way, as long as you have a method that completes the bleeding without air in the lines at a speed that works for you.

 

[Mellow]

+1 on Paul's comments.

Some people thing the vacuum is adding air to the system because of the bubbles you see but that's only because the hose to bleeder is not usually tight... the pressure is pulling so it will pull fluid and not allow air into the system.

There are many ways to bleed the system and they all work fine. So, you are good.

 

[SupraSabre]

I usually start off with the vacuum and then do a couple of lever/pedal (while leaving the vacuum attached) at the end to make sure they still feel firm!

 

[dduelin]

Vacuum pumps help me when the lever or pedal is on the other side or end of the bike and it's too far for my hands to reach both and I do not have a helper.

 

[SupraSabre]

... and I do not have a helper.

What's a "helper"?

 

[JimGregory]

Vacuum equipment is not needed, but it can speed up the process. I too have always used the lever pump method, synchronizing each lever action with an opening then closing of the bleed nipple. As long as the reservoir is kept filled with fluid, no air is pulled into the system.

One of the issues of any other technique is that the threads at the bleed nipple leak in air--many folks wrap the nipple threads with Teflon tape to reduce that, or like me we close the nipple at the end of every lever stroke so that air isn't pulled back in through those threads.

There is no right way or wrong way, as long as you have a method that completes the bleeding without air in the lines at a speed that works for you.

Actually I start with the open\close method. Then with an upward loop in the clear bleeder hose, I then just pump a reservoir (or two) full (through each stage), then finish with the open\close method.
worked great for my first time flush. Got some air out, fresh fluid in, and a firm pedal back.

 

[JimGregory]

Vacuum pumps help me when the lever or pedal is on the other side or end of the bike and it's too far for my hands to reach both and I do not have a helper.

I used a wooden broom stick handle, Does not slip on the diamond pattern pedal.
A third eye on the reservoir would be a big help though!
I actually DO have a vacuum bleeder. I used it once. For me it was a bit messy, so I bagged it and went back to my long tubing and a bottle, with a check valve close to the bleeder.

 

[dduelin]

I used a wooden broom stick handle, Does not slip on the diamond pattern pedal.
A third eye on the reservoir would be a big help though!
I actually DO have a vacuum bleeder. I used it once. For me it was a bit messy, so I bagged it and went back to my long tubing and a bottle, with a check valve close to the bleeder.

I use a 1/4 by 2 wood slat for this. The long circuits need a few pumps of the pedal to speed things up. And yes, I've let the rear reservoir go dry once. Since then I pump the pedal no more than 8 strokes or so from full w/o eyeballing it.

 

[JimGregory]

And yes, I've let the rear reservoir go dry once. Since then I pump the pedal no more than 8 strokes or so from full w/o eyeballing it.

You read between the lines! I hate that noise. The noise of failure.

 

[SupraSabre]

Me too. Yesterday(you read between the lines didn't you). Don't tell anyone. I hate that noise it makes!
Good rule 8 strokes.

Oh, you mean that empty cup with a straw sound? I've never heard it! 4:

It took me forever to get my clutch back on the '04 a few weeks ago! A combination of the vacuum and lever finally got it back!

I hate when that happens!

 

[BakerBoy]

Glad to hear I'm not the only one who's happened to pump a reservoir empty a time or two. :

I never have a helper. So I lay on the floor where I can reach the rear pedal while working the rear caliper nipple. But the hardest for me given certain joint pains is to contort to both reach the front lever and the left front caliper nipple (of course, unable to see the fluid level). Once I get into a workable posture, I want to keep at it (it is difficult to convince myself to stop and check the reservoir level . Just this past Saturday, I pumped air into the RT's front line for that very reason. Ugh! Took an extra couple reservoir's fillups and pumpouts, and cycling the ABS motor, to clear the bubbles. Fortunately the RT's brake lines are simpler than the ST's linked system.

Next time, I'm going to have a flexible mirror mounted so I can see the fluid level in the reservoir. And I'll count lever pulls--good idea Dave!

 

[Bush]

Speed bleeders - no gymnastics required.

 

[Al Gully]

One way valve brake bleeder is what I use.
Best $11.69 I ever spent on my brakes system.

Motion Pro 08-0143 Hydraulic Brake Bleeder

 

[JimGregory]

Speed bleeders - no gymnastics required.

How do you know when the air is out? How do you know when the fresh fluid is in? Not saying it's a bad thing. I just already own the stuff to get it done.
Basically the same thing as the check valve I use I think. Still gotta put an eye on it though.

 

[Bush]

How do you know when the air is out? How do you know when the fresh fluid is in?

Simply by standing on either side of the bike, working either the brake or clutch levers and watching the clear tubing attached to the bleeder nipples for any air bubbles and new clear fluid to come through, while easily keeping an eye on the reservoir levels too.

 

[Rekoob]

One way valve brake bleeder is what I use.
Best $11.69 I ever spent on my brakes system.

Motion Pro 08-0143 Hydraulic Brake Bleeder

I use the same one.

Although I have had issues with air between the bleeder and the check valve, just can't seem to get that to stay full of fluid at times. I have to assume its the bleeder threads leaking in some air and yes I have tried putting the Teflon tape on the threads.

I end up using the open/close bleeder and as stated the reach is a problem at times.

If anyone has pointers I willing to give it a try on my next bleed.

 

[drtyrrel]

When doing the PCV bleeder do you just pump the rear pedal? How about the SMC, the pedal and pump the SMC actuator? Also if replacing all the fluid and bleeding how much fluid will it take?

 

[jfheath]

Plugging my own post here, but take a look at my article on Getting all of the air out of the system. Its all to do with locating and getting rid of the trapped air. There's a video and a pdf file. The images on the post are taken from the pdf file, but the pdf contains the explanations.

For me, the vacuum bleeder provides the continuous steady flow that is required in order to get rid of the bubbles from the system. It can be hands free - providing that you keep an eye on the reservoir level, which means you can go round tapping joints, flexing hoses and activating the SMC - all of which helps to release the trapped bubbles and allow the trapped dirty fluid to be flushed out at the same time.

It is well worth a look. I learned a lot from thinking about this before I wrote the article, and the behaviour of the bubbles in a tube really surprised me. I knew that they could get stuck, but it was where they got stuck that was a bit of a revelation. The video of one of my experiments is on the first post of the article.

ps

I use the vacuum bleeder first off. When I think I have all of the air out (You can't tell as the vacuum pump sucks air from outside, past the threads of the bleed valve !) Then I revert to the tube and jar method - with a one way bleed valve.