Let's discuss bleeding brakes!

[AZhitman]

New homepage article, let me know what you guys think.

Bleeding Your Brakes - The RIGHT Way

[elwesso]

I really like the idea of back-flushing things.. However the one question I had, how did you recover the fluid from the master cylinder? Obviously you have to be sure not to spill any fluid on any painted surface..

[AZhitman]

I used another (old) vac pump. I've got an old beat-to-hell MityVac hooked to a Gatorade bottle. It's on its last legs, but it's ok for simple stuff like emptying a M/C.

[MinisterofDOOM]

To be completely honest, brake bleeding is one of the few basic maintenance things I've never done myself, simply because it has always seemed so tedious. I should probably pick up a bleeder system like this so I don't have that excuse anymore.

[elwesso]

To be completely honest, brake bleeding is one of the few basic maintenance things I've never done myself, simply because it has always seemed so tedious. I should probably pick up a bleeder system like this so I don't have that excuse anymore.

Bleeding brakes is way easier than most other things.. I'd rather bleed brakes/change brake fluid than change transmission fluid, in either an AT or MT...

[frapjap]

What is the advantage of this system over vacuum bleeding? Other than being able to perform this one at home?

[elwesso]

I think the major advantage is that you're actually pushing NEW fluid into the calipers and flushing out everything back through the system... Obviously it's most important that the calipers have fresh fluid and no contaminants, so by forcing the fluid through at the caliper, you guarantee that the fluid is fresh and as clean as it can be, versus sucking it through from the master cylinder.

Also, since you're pushing the fluid uphill, you have a better chance at getting the air out since obviously air is lighter than brake fluid...

[AZhitman]

^ That.

Plus, it's neater / cleaner. Typically, vacuum bleeding isn't really "vacuum bleeding", since you'd have to either have a supplemental reservoir of fresh brake fluid at the MC (or someone to keep topping it off).

And, of course, the old "pump-pump-hold-crack-close" method is pretty substandard and risky.

As a side note, this system also will perform a vac bleed - it'll even do all 4 calipers at once. It's got all kinds of nifty attachments and such.

[elwesso]

As a side note, this system also will perform a vac bleed - it'll even do all 4 calipers at once. It's got all kinds of nifty attachments and such.

Could you do the "push" method to all 4 calipers at once? That would be really cool, just run your lines to the bleeders and whammy them all at once...

Also another thing that this will eliminate, and anyone who's done brakes the old fashioned way will know this... If you get air into the master cylinder by letting the fluid get too low, that is a HUGE pain to fix. If you're pushing the fluid "out the in", there's no chance of this happening, and if it was done in the past, it would be fixed for sure.

[AZhitman]

Probably - I don't see why not. Although, considering the distance differences, it really wouldn't make much sense - You'd wind up disconnecting the fronts about one stroke into the job.

Definitely agreed on the second part. My damn Roadster (with the bleeders pointing down, and a big loop in the brake lines above the calipers) is a perfect candidate for it.

[gwoods]

your buddies z06 may need new tires the one in the photo looks very near or at the wear bars :-)

I have always used a vac tool with good success. The hardest bleeding is on a new system so much air!

$185 is a bit steep for a tool like that. How did it seem to handle the brake fluid? I know the vac tools I buy from harbor freight fail after about 2 years from exposure to brake fluid and its destructive ways.

[AZhitman]

Not steep at all when you see everything else that comes with it. Considering it's made for shop use, and brake flushed aren't cheap, it's a moneymaker.

The seals and such are made of a fluid-resistant material, unlike HF vac tools.

It's also rebuildable, which is pretty cool.

[gwoods]

Cool want to go half on it... baby?

[AZhitman]

Ummm, I already have it.

But you're welcome to come over and use it... baby.

[gwoods]

I did just buy a Miata 5spd, clutch, pedals, flywheel and all the lines and connectors for $200. I could probably use it to bleed the clutch might have to come by!

[WDRacing]

I'm lazy, I just suck out all the fluid in the MC and wipe out the residue. Refill it with new whatever fluid I have in bulk. Usually coincides with oil changes. I don't ever bleed anything unless I open a line, which I avoid at all costs.

[Infinitiguy19]

Reverse bleeding brakes seems like a bad idea to me. It seems to me that most of the rubber is near the calipers (Flex hoses, Seals...) The Master Cylinder has a few rubber seals that will cause the fluid to get black in color. But why push the dirty fluid back towards the ABS module and Master Cylinder?

Will a Master Cylinder fail because its pushed beyond its designed limit by doing a 2 person brake bleed?

Also air getting into the brake system by way of the brake bleeders can be solved with thread sealant right?

[the converted]

I'm not a huge fan of reverse bleeding for exactly that reason. With all this fancy ABS stuff that most cars have, I would think it would be bad, but I have no real evidence to back up my hunch. I've used a few pressure bleeders with good results.

All that said it does look like a good product, especially for someone that has bleeders on the bottom and other weird issues to deal with.

[Red coupe]

Will a Master Cylinder fail because its pushed beyond its designed limit by doing a 2 person brake bleed?

Probably not...

I have heard the reasons its bad... But never heard of or seen a single failure due to bleeding.
We sure do it a TON on our race car. The current master cylinder has multiple e3 wins at the 25 Hours of Thunderhill, and was named the NASA WERC grand champion... and has done 3 years or so of endurance events, all while being bleed multiple times a weekend with one person in the drivers seat and one on the caliper. I can guarantee that master has significantly more bleeds then any car getting an annual brake flush.
Thats my experience anyways...

[float_6969]

I use speed bleeders on all 4 calipers. Completely possible to do alone, but it's a pain. Easier to top off the MC, and have a friend watch the hose and holler when it's clear/no air. I've never had consistent luck getting all of the air out of the system using vacuum, so I gave up on it.

[Looneybomber]

Ok, from a guy who's never really done much with car brakes. I might have watched Float do his brakes or pump on a pedal while having a beer, but I've flushed brakes on a motorcycles. So here's my question, (n00b alert) why not open the nipple/bleeder, and drain the fluid while someone pours in new fluid? Gravity does the rest. Go to the next caliper until all four have clear fluid coming out. Done. Right? Only requires a wrench.

[AZhitman]

So here's my question, (n00b alert) why not open the nipple/bleeder, and drain the fluid while someone pours in new fluid? Gravity does the rest.

Because of the fact that fluid in a narrow tube (due to capillary action and other liquid properties I'm too dumb to understand) will "adhere" and not flow. Think of a soda straw... if you pull the straw out of the soda, some liquid remains in the straw. It doesn't give a s*** about gravity. You can shake it, or blow it out, but why does it stay in the first place? Now, reduce the diameter to 1/10th of a straw, and you'll see why gravity can't be relied upon. Plus, on a low car, the M/C isn't too much higher than the bleeders (on my Miata, it's maybe a foot).

Plus, lots of cars have high points in the lines (arches or bends) where air gets trapped. Fluid will push the air aside briefly, but it will find its way back to the high point. It has to be forced to the M/C (or the bleeder).

[AZhitman]

But never heard of or seen a single failure due to bleeding.

Impossible to tell if the failure a year from now is due to an improper bleed procedure or just age. Might it have failed anyway? Sure... but who can know? Could it have functioned another 10 years with a proper bleed? Possibly... but who can know.

If you disassemble a M/C you can see the ridge in the bore that demarcates the normal stroke from the rest of the bore. Moving the seal past that ridge has to compromise the seal, even if it's the tiniest of damage - there's no real way it can't.

I'm guessing a race car isn't using a standard mass-produced poor QC OEM M/C, either.

[WDRacing]

Speaking of brakes, my Mom's brakes totally failed on her Taurus last week. Fortunately for her, it happened to the mechanic that was moving her car from the shop to the parking lot after a fluid change and inspection. One of the rear brake lines gave out because of corrosion.

Pretty off-topic but since the weather is currently awful and the salt content on the roads isn't getting better for at least 2 more weeks, don't forget to hit the drive-thru car wash that has an undercarriage sprayer. The underside of your car will thank you.

[Red coupe]

But never heard of or seen a single failure due to bleeding.

Impossible to tell if the failure a year from now is due to an improper bleed procedure or just age. Might it have failed anyway? Sure... but who can know? Could it have functioned another 10 years with a proper bleed? Possibly... but who can know.

If you disassemble a M/C you can see the ridge in the bore that demarcates the normal stroke from the rest of the bore. Moving the seal past that ridge has to compromise the seal, even if it's the tiniest of damage - there's no real way it can't.

I'm guessing a race car isn't using a standard mass-produced poor QC OEM M/C, either.

All I can say is the part you cut out,

We sure do [bleed brakes] a TON on our race car. The current master cylinder has multiple e3 wins at the 25 Hours of Thunderhill, and was named the NASA WERC grand champion... and has done 3 years or so of endurance events, all while being bleed multiple times a weekend with one person in the drivers seat and one on the caliper. I can guarantee that master has significantly more bleeds then any car getting an annual brake flush.

Definitely on unmodified OEM Mazda MC. Only modification to the brake system outside of cryo treated rotors and high quality brake pads from the good folks at Porterfield is a Wilwood proportioning valve mounted to the transmission tunnel on the passenger side of the transmission.

You're right that there may be a ridge... But I'd also add that boring the MC is likely done in one operation with no planned step added, and no reason to not finish the entire travel and leave a sharp edge, so the ridge is likely formed by the travel of the piston... and isn't going to have a sharp edge to cut the seal that formed it in the first place. All that is speculation though... what I KNOW is that I have bleed the same cylinder the same way many many more times that anyone of you have bled your personal vehicle (I personally have not counted, but more then 20 times easily) without issue... And the same goes for most paddocks I look into (amature to pro, sprint to endurance).
As always, you pick the level of risk you're willing to accept. My personal experiences dictate the risk is pretty damn low.

[the converted]

I have personally killed a master from bleeding. It was on a car that hadn't had the fluid bled in years, so over the years as the moisture built up in the fluid and caused some corrosion in the bore. The area that was usually swept was clean, but once you got past it was a mess. Bleeding it that way destroyed the seals and killed the master.

Now in a race car that has the brakes bled constantly, you're not going to have any of the corrosion from the moisture, so not going to be an issue in that situation. Our shop has a policy of pedal bleeding only as a last resort, and even then only with a block under the pedal.

[Looneybomber]

Plus, lots of cars have high points in the lines (arches or bends) where air gets trapped. Fluid will push the air aside briefly, but it will find its way back to the high point. It has to be forced to the M/C (or the bleeder).

Makes sense. I only pictured bikes where the reservoir is above the bleeders with minimal interruptions and my explorer where the MC is well above the calipers.

[AZhitman]

Now in a race car that has the brakes bled constantly, you're not going to have any of the corrosion from the moisture, so not going to be an issue in that situation. Our shop has a policy of pedal bleeding only as a last resort, and even then only with a block under the pedal.

Makes sense. I guess I'm thinking worst-case, which is more typical than not (cars that haven't had a wrench on the bleeder since they were installed at the factory).