Changed my brake fluid with ATE and ... WOW

[kgb007stb]

Thanks to everyone for recommending ATE brake fluid.

I finally got around this weekend to flushing my brake lines with ATE brake fluid and boy do I see a difference in my braking performance. This was on a 5 year old car with 41k miles on it, the brake fluid looked like the factory stock and two things amazed me right from the get go. 1. The amount of initial black gunk that came out of the rear calipers. This confirmed that the brake fluid will break down fast as it is cycled through the various heat stages. 2. The few air bubbles that cam out of the system. I am not sure whether this was due to the old brake fluid breaking down or someone (factory or mechanic) not doing a proper brake flush.

In either case I am happy I finally got around to it as my brakes perform so much better with a much firmer pedal feel through all the various braking stages. Now when I hit the brakes hard, the car does not pull to the right side any more as all calipers apply equal amount of pressure. The heat cycling also tends to harden the bleeder screws so I was happy that none were stuck and everything went through flawlessly. What an improvement on just stock brakes, I would only imagine what this type of maintenance must do to high performance brakes. I am also happy that the new fluid will prevent any type of rusting in the lines or calipers.

One minor complaint, my calipers do not have a bleeder screw on the bottom to flush out all the gunk that accumulates at the bottom. I was happy to see the gunk leave through the top, yet it would be nice to have that bottom bleeder screw so that everything would be evacuated through the bottom not giving it any chances to get stirred up.

Like everyone says here, do not overlook your brake maintenance, especially on used cars where previous maintenance is unclear.

 

[Kestas]

Rather than the manufacturer adding another bleed screw, the gunk is cleaned out by taking the caliper apart. Sometimes the gunk on the bottom is impacted onto the caliper bore. Even if there was a bleeder screw it wouldn't come out.

 

[Auto-Union]

No point in flushing/bleeding unless the caliper cylinder piston is pushed back into the bore and it's cleared of old fluid completely.

 

[unDummy]

Bleed more often to prevent crud buildup, to keep additive package fresh, and to reduce moisture and air buildup.

Instead of praising the ATE, praise the 'bleed'. Any brake fluid would've improved your pedal feel if air is bled out.

Bleeder screw location isn't optimized to remove gunk. Its up top to help remove the air.

If you bleed yearly(recommended) or every 2 years(minimally), you don't have to worry about any gunk that has settled.

 

[JTK]

Uh-oh... labman, don't look!! (j/kidding!)

Joel

 

[labman]

In a functional system, the brake fluid doesn't touch the outside of the lines where the rusting occurs. Well, maybe if you use ATE, it will eat through from the inside.

 

[par]

I would bet that a LOT of your performance increase is a result of just bleeding the system and nothing else. Of course, it is always good to replace the fluid on a regular basis.

 

[oil pan 4]

If you have any kind of off road toy you will find your self dumping and cleaning the break fluid tank once a year just about and beeding the breaks every few months.
For me I like not going off the trail and crashing.

 

[moribundman]

You can buy 'Strip-Dip' brake fluid test strips that will tell the condition of brake fluid.

 

[labman]

I don't about other brands, but in general the GM factory fill, and the Prestone I replace it with eventually, lasts at least 10 years by which time the rubber parts of the brakes system are aged and worn beyond reliability. Changing brake fluid is a bunch of hooey for most people. Maybe needed in some foreign makes.

 

[moribundman]

http://www.aa1car.com/library/bfluid.gif


Excerpt from the linked article:

quote:

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Many experts have long recommend changing the brake fluid every year or two for preventative maintenance. Their rationale is based on the fact that glycol-based brake fluid starts to absorb moisture from the moment it is put in the system. The fluid attracts moisture through microscopic pores in rubber hoses, past seals and exposure to the air. The problem is obviously worse in wet climates where humidity is high.
After only a year of service, the brake fluid in the average vehicle may contain as much as two percent water. After 18 months, the level of contamination can be as high as three percent. And after several years of service, it’s not unusual to find brake fluid that contains as much as seven to eight percent water.

An NHTSA survey found that the brake fluid in 20% of 1,720 vehicles sampled contained 5% or more water!
As the concentration of moisture increases, it causes a sharp drop in the fluid’s boiling temperature. Brand new DOT 3 brake fluid must have a dry (no moisture) boiling point of at least 401 degrees F, and a wet (moisture-saturated) boiling point of no less than 284 degrees. Most new DOT 3 fluids exceed these requirements and have a dry boiling point that ranges from 460 degrees up to over 500 degrees.
Only one percent water in the fluid can lower the boiling point of a typical DOT 3 fluid to 369 degrees. Two percent water can push the boiling point down to around 320 degrees, and three percent will take it all the way down to 293 degrees—which is getting dangerously close to the minimum DOT and OEM requirements.
DOT 4 fluid, which has a higher minimum boiling temperature requirement (446 degrees F dry and 311 degrees wet) soaks up moisture at a slower rate but suffers an even sharper drop in boiling temperature as moisture accumulates. Three percent water will lower it’s boiling point as much as 50%!
Considering the fact that today’s front-wheel drive brake systems with semi-metallic linings run significantly hotter than their rear-wheel drive counterparts, high brake temperatures require fluid that can take the heat. But as we said earlier, the brake fluid in many of today's vehicles can’t because it is old and full of moisture.
Water contamination increases the danger of brake failure because vapor pockets can form if the fluid gets too hot. Vapor displaces fluid and is compressible, so when the brakes are applied the pedal may go all the way to the floor without applying the brakes!
In addition to the safety issue, water-laden brake fluid promotes corrosion and pitting in caliper pistons and bores, wheel cylinders, master cylinders, steel brake lines and ABS modulators.

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Excerpt from the same article:

OEM BRAKE FLUID RECOMMENDATIONS

What do the auto makers say about fluid changes? General Motors and Chrysler do not mention brake fluid in their scheduled maintenance recommendations. A General Motors spokesman said Delco Supreme 11 DOT 3 brake fluid contains additives than many other brake fluids do not, so it is essentially a lifetime fluid. Starting in 1993, GM began using a new type of rubber brake hose with an EPM lining and outer jacketing that reduces moisture penetration by 50%. So GM does not consider fluid contamination to be a significant problem.

Ford, however, recently changed its position and now recommends fresh fluid every 36,000 miles or three years—and to replace the fluid each time the brake pads are changed.

Several import vehicle manufacturers also recommend brake fluid changes for preventive maintenance. BMW says the fluid should be changed every two years. Honda recommends a flush & fill every 25,000 to 30,000 miles. Subaru also recommends a 30,000 mile brake fluid change. Volkswagen recommends changing the fluid every two years, and clearly states this in their owners manuals.

If motorists would only follow this simple advice to change their brake fluid periodically, they could greatly reduce the risks associated with moisture-contaminated brake fluid. The could extend the life of their brake systems and likely save themselves a lot of money in the long run—especially if their vehicle is equipped with ABS (because ABS modulators are very expensive to replace!).

 

[VNT]

But what if one freshens the fluid every 6 months by the reservoir?? I do it to all my cars 2 or 3 times a year and the color in the resrvoir never darkens much.

I have never bled my brakes on my 20 year old car and never have has an issue with a caliper. When I upgraded the brakes with SS braided flex line the fluid which came out when I removed the lines at the caliper was clean. This is for front and back.

I dont disagree that bleeding the brakes every few years and adding fresh fluid is bad, but if one freshens the brake fluid, I would think that it would be adequate.

 

[moribundman]

Anybody is free to do as he wishes. I tend to follow the factory manual.

 

[Kestas]

Let's not also forget the issue of contaminant copper in solution -- important for cars with ABS systems.

From the archives: http://www.babcox.com/editorial/bf/bf50412.htm

 

[wantin150]

VNT,

Do you have any additional wear issues with the SS lines? I have heard that they are a little more maint intensive as dirt can get trapped between the braid and the hose causing the hoses to wear more rapidly.

 

[moribundman]

Even if no dirt gets through the braiding, you can't tell the condition of the hose under the steel braiding. I can't stand cloth-covered vacuum tubing for the same reason.

 

[VNT]

No issues other than instant braking when you step on the pedal the brakes are there, best upgrade I have ever done. These are on 86 Shelby 11" discs all around on a Turbo Z CS and a 89 Shadow ES turbo.

quote:

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Originally posted by wantin150:
VNT,

Do you have any additional wear issues with the SS lines? I have heard that they are a little more maint intensive as dirt can get trapped between the braid and the hose causing the hoses to wear more rapidly.

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[bar1]

quote:

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Originally posted by VNT:
But what if one freshens the fluid every 6 months by the reservoir?? I do it to all my cars 2 or 3 times a year and the color in the resrvoir never darkens much.

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And how would the fluid in the reservoir get dirty? The fluid isn't circulating so your fresh fluid would stay in the reservoir.
Your suggestion isn't just bad, it's dangerous. Only a complete flush every 2-3 years will give you safe brake performance..

 

[V1]

I am all for the flush. A turkey baster just doesn't cut it if you ask me.

First off, the amount of time it would take to completely replace the fluid by way of the resevoir vs a flush is several fold. Plus it will take much more fluid to do a complete job. Plus you don't get crud out from deep within the system (i.e. ABS, lines, calipers). There is all sorts of garbage in there that the turkey baster method just can't tackle.

 

[unDummy]

The brake fluid might not circulate, but there is plenty of fluid movement from the hundreds of times a week that you step on the pedal. So, there is plenty of mixing. Plus, fresh fluid with no moiture will pull moisture from the rest of the brake system evening out the moisture level.
IMO, there is nothing wrong with refreshing the master cylinder 3-4 times a year. And, if anything, it sure beats doing NOTHING. But, you still should bleed the brakes minimally every 2 years. And, I will still recommend yearly bleeds for everybody regardless of any stupid owners manual recommendations.

Strip dips, IMO, are a waste off money unless you own a shop and are trying to sell the 'bleed' on a regular basis.

There is no crud in the brake system if the fluid is kept fresh. So, turkey baster away. I've adapted a basketball filler to the oil extractor which siphons the master cylinder empty in about 20 seconds. And, when I bleed, I find that the brake fluid is cleaner compared to vehicles that have never experienced the 'turkey baster'.

Noone is saying that the 'turkey baster' is a substitute for the 'bleed'. Please don't draw that conclusion.