Reverse brake bleeder

[unDummy]

Opinions on the reverse brake bleeder(forcing brake fluid from the bleeder backwards into the master cylinder).

My only issue is keeping the master empty since most here know my opinion on kitchen tools used on the car. And, the poor seal at the bleeder thread might be annoying.

http://www.brakebleeder.com/index.php?main_page=product_info&cPath=2&products_id=14

Reverse bleeding reminds me of bench bleeding hydraulic components prior to installation.

 

[CharlieJ]

Why would you want to reverse bleed the system? IS there a specific reason? For that price, it would be a lot cheaper to buy speedbleeders for all four wheels.

 

[unDummy]

Because, the infomercial said that we've been doing it wrong for a bazillion years.

Speedbleeders are too expensive to attach to every car that drives into the service bay.

BTW, I have a Motive, a Mityvac, can gravity and 2-man bleed with the best of them. And, sometimes, I have to 'repeat' or combine to get that perfect pedal.

The little video shows that sometimes there is a stuck pocket of air in some systems. Might just be more effective sending it 'UP' as that is the way bubbles want to move when in a fluid. Bleeding a bubble down doesn't work as well as we think. You'd notice this if you ever used gravity and a hose to siphon a reservoir dry.

Whoever got the reverse bleed product patent is a genius. But, I think there is a minor flaw in the reverse bleed loop. Can't find an owners manual for it yet to confirm the method.

 

[Quest]

I've used 2-man bleeding, vacuum, and motive. So far, my preference (based on speed and how well it works) would still be motive, hands down. It gets the job done a bit slower than that of a vacuum pump but less messy and less likeliness of accidentally introducing bubbles into the hydraulic system.

Q.

 

[Ken2]

How much crud from old, dirty wheel cylinders and calipers might the reverse bleeder push into other parts of the system?

 

[XS650]

Quote:
How much crud from old, dirty wheel cylinders and calipers might the reverse bleeder push into other parts of the system?


All of it that is loose.

 

[HTSS_TR]

I've used 2-person bleeding, Motive, and Mityvac. My preference would be Mityvac, it gets the job done faster and cleaner than Motive. Before I tried Mityvac I thought that Motive is the best 1-person bleeding tool. After I tried Mityvac I'm going to sell my Motive that I used only once.

 

[Saleen0679]

Originally Posted By: unDummy
Can't find an owners manual for it yet to confirm the method.


I've been wanting to at least try one of those Phoenix systems for a while just to see if it works any better/easier than other methods I've used. You can get the V-12 system a lot cheaper at any of the online tool shops.

User's manuals are at:

http://www.phoenixsystem.com/general_information/manuals/index.htm

 

[KrisZ]

Siphoning is not exactly the same as brake bleeding. This product is smartly marketed because the principle makes sense on the surface and people will think “…hmm they’re right, bubbles in water do rise to the top…” but in reality it addresses a "problem" that doesn't exist.

The brake lines can be compared to a straw. Just pick a transparent straw and draw in some fluid with air bubbles in it, hold one opening shut and look at the bubbles. They remain stationary, they will not move up, release your finger from the opening and the bubble will flow in the direction of fluid. That's because the bubble will have surface tension in the straw's walls, that's what keeps the bubble stationary, tap the straw to break up the surface tension and the bubble will start moving.

Brake lines are really thin, so the bubbles that are big enough to touch walls, will be held by surface tension, the really small bubbles will have too little air volume to overcome fluid friction and rise to the top. Siphon tubes are much bigger in diameter, therefore air bubbles have much more air volume that can easily overcome the internal fluid friction.

So in other wards, this device may work and bleed brake lines just fine, but so does any other method mentioned in this thread.

 

[BBDartCA]

Originally Posted By: KrisZ
Siphoning is not exactly the same as brake bleeding. This product is smartly marketed because the principle makes sense on the surface and people will think “…hmm they’re right, bubbles in water do rise to the top…” but in reality it addresses a "problem" that doesn't exist.

The brake lines can be compared to a straw. Just pick a transparent straw and draw in some fluid with air bubbles in it, hold one opening shut and look at the bubbles. They remain stationary, they will not move up, release your finger from the opening and the bubble will flow in the direction of fluid. That's because the bubble will have surface tension in the straw's walls, that's what keeps the bubble stationary, tap the straw to break up the surface tension and the bubble will start moving.

Brake lines are really thin, so the bubbles that are big enough to touch walls, will be held by surface tension, the really small bubbles will have too little air volume to overcome fluid friction and rise to the top. Siphon tubes are much bigger in diameter, therefore air bubbles have much more air volume that can easily overcome the internal fluid friction.

So in other wards, this device may work and bleed brake lines just fine, but so does any other method mentioned in this thread.


Good points. Phoenix makes claims pressure bleeding is preferred by GM and Bendix. Not sure f this is true or not. I know Bendix in some systems advises against anything but manual bleeding (pressing the brake pedal) as the miti-vac or other one man systems do not develop enough pressure to remove air.

I had one of the Phoenix pressure bleeders and found the quality to be very poor and did not work any better than the miti-vac sucking method.

 

[mechtech2]

Gravity bleeding IS pressure bleeding [just with less pressure than a special device].

The nice thing about a Mity Vac is it fits ALL cars, and is pretty foolproof. Needing only one guy is a huge plus!

Reverse bleeding? I dunno... even Rap music has it's adherents.

I see problems with seals. Under pressure, they could expand out and not flow . Normal bleeding has the seals operate in an optimal direction.
Also, ABS systems may be goofed up with this.

Air in a system will migrate up anyways, unless it its trapped.
Brake systems and vehicles are far from static. Normal bleeding seems best for me, at this point.

 

[Smoky14]

Reverse bleeding is really effective on motorcycles. The low capicity of the system and the near vertical lay out of the plumbing make normal bleeding difficult. YMMV

 

[hustler]

I'm fighting with a bleed right now on the track car after replacing the master cylinder. I'm going to try reverse bleeding tomorrow with the Motive bleeder because I'm tired of chasing my tail.

 

[mechtech2]

Did you 'bench bleed' the master first?

 

[hustler]

I did. After another day of going in circles and contemplating suicide, I tried the reverse bleed. I'll spare you the logical details and just let you know that it worked and for the first time in this car I have good hydraulics.

 

[bimmerdriver]

Originally Posted By: hustler
I did. After another day of going in circles and contemplating suicide, I tried the reverse bleed. I'll spare you the logical details and just let you know that it worked and for the first time in this car I have good hydraulics.
Forcing brake fluid up into the master cylinder from a caliper sounds like a good way to push dirt from the caliper into the master cylinder. If that helped get the air out that's good, but you might want to try a regular bleed to ensure that there is no dirt and/or contamination from the calipers in the system.

 

[unDummy]

Its not an issue. Flush the brakes 1st then reverse the bled.

 

[hustler]

The real problem is how the Miata brake lines go vertical out of the MC, then about 2-feet of hirizontal line above the MC...so I'm still trying to chase the air out.

Reverse bleeding is for dry lines, simple logic and grammar school intelligence tells you not to reverse bleed oil fluid through the system.