Brake flush on my Truck

[vping]

I had my trunk inspected by a very reputable Mechanic - voted best on Long Island....No problems. Truck is my 2004 Ford Expedition.

I need tires so I took it over to Mavis. He tells me I need to flush the brake Fluid. Whether or not I need to, how do you? I've change the fluid on the B's but this is power brakes. Is there anything else I need to do besides fill, pump, check, repeat?

 

[rlwhitetr3b]

The Mazda dealer suggested that for my Miata the last time I had it in for an oil change.

I had never heard of that as normal maintenance. Is this something that is normally done now? Maybe it has always been recommended and I'm just a negligent owner.

 

[vping]

The tire guy told me every 30,000. I've just hit 58,000 so He says I am due for my 2nd change.

 

[RonMacPherson]

All the rest of the world auto manufacturers recommend a brake fluid system flush every two years or 30000 miles, or more often under severe conditions.

None of the American dealers have that recommendation in any of their owners/service manuals(last checked in early 2007) Chrysler says not to flush the brake fluid....(Better engineering???) GM used to have their dealers keep the litmus paper strips in their service advisors offices so the advisor could check the fluid when the car was in the driveway. Ford was "as required". But that may have changed...

 

[vping]

I have another truck, a 1991 Ford Ranger which I have owned since day 1. I've never changed it and it has 132,000 miles on it. So maybe it's bunk.

 

[Silverghost]

Just my 2 cents here.....seems to me that with gas on the rise, and people driving less, there is less demand for service and so......and who wants to risk their brakes after all....nice - or not so nice - way to play on the fears of the average driver.... This brake system flush is new to me too....

 

[JPSmit]

DOT 3 brake fluid absorbs moisture - my understanding is that the moisture diminishes braking ability over time as well as causes rust. hence (In my understanding) the need to flush & replace

 

[bugimike]

DOT 3 brake fluid absorbs moisture - my understanding is that the moisture diminishes braking ability over time as well as causes rust. hence (In my understanding) the need to flush & replace

at least with older stuff! Newer systems may not need it, but don't quote me on that!! If the brake fluid does not look clean and fresh, i would flush and replace as a matter of course!! :wink:

 

[RonMacPherson]

For those who think that they can keep driving their american autos and put hundreds of thousands of miles on them without needing to replace the brake fluid.


You've been doggone lucky, probably living in a very low humidity environment. Make sure your dependents are named in your life insurance policies. They may collect.

Dot 3 and Dot 3 brake fluid is hygroscopic. i.e. it absorbs moisture from the atmosphere. Some system designs on master cylinder caps can keep that humidity encroachment to a minimum. But it still happens.

What happens when the moisture is absorbed? The brake fluid turns acidic. It attacks the seals in the rubber and the metal in the cylinders. I'm sure everyone has seen the white crust around a leaking wheel cylinder at some time of their life. Those crystals didn't just appear with the wave of a magic wand...

Be Safe, replace your brake fluid. I recommend every two years and 30K miles. You may get longer than that(I see Daimler Chrysler vehicles with their rear wheel cylinders start leaking at around 47K miles)this is with regularity...

Don't be sorry.

 

[sparkydave]

Ron is right, just because it's not normally called out doesn't mean it's not needed. My dad's cars all had hundreds of thousands of miles, and he never changed it unless he had to open the hydraulics. Needless to say, the reason he had to open the hydraulics was when the rusty brown sludge in the cylinders caused problems. The car he loaned to me in school needed new wheel cylinders because the old ones were badly pitted, rusty, and had started leaking. When I got them apart, the brake fluid was black as coffee and had turned to sludge. With my last two cars, they called for routine brake fluid changes, and although the fluid comes out brown, it's not sludgy and rusting the hydraulics.

Don't forget that the added moisture not only promotes corrosion, but lowers the boiling point significantly too. If you have to use the brakes hard you will lose them completely if it boils when it's not supposed to.

Incidentally, the two cars called for changes based on time (every 2 years) and not mileage. Makes sense; the amount of moisture in it would be more a function of time than mileage.

P.S.: Don't forget the clutch fluid either. Same stuff, same problems.

 

[JerryB]

""""""Is there anything else I need to do besides fill, pump, check, repeat?"""""""""""

If you have ABS there MIGHT be a special procedure of bleeding depending on the type of your ABS system.


"""""I had never heard of that as normal maintenance.""""

Just like all fliuds there is a timeline.

Remove the m.c. lid and if the fluid is brownish your due. The absolute test is with brake fluid test paper (litmus type paper) that changes color with fluid degredation.

 

[vping]

So to be safe I should probably have it done. I'll do it on the B's but the truck I leave to the pro's especially because it's my daily driver.

 

[Banjo]

The litmus strips we had at the dealer tested the fluid for the presence of copper. Don't ask me why. I tested fluid that was nasty black and it tested fine. I don't think that Toyotas have much copper in thier brake systems to contaminate the fluid. Still reccomended the flushes though. It was the moiusture I was concerned about.

 

[PAUL161]

I flushed my Chevy truck at 150,000 miles because it was very dark in color. Now it's spiffy clean! My truck has ABS brakes and all I did was push the old fluid back from the wheel cylinders,pumping out the old fluid from the master cylinder reservoir as I went. Works fine. No problems.

 

[Scott_Hower]

I replace every two years on my and SWMBO's daily drivers.

 

[Guest]

Very good post.... The dot "3" "4" "5" number is the indicator in percentage as to how much moisture the brake fluid can absorb before it is saturated beyond safe operating limit.... 3 percent isn't much by volume, either... so 2 years is max. Another point that is EXTREMELY important! NEVER EVER EVER put silicon brake fluid in an ABS unit! IT WILL CAUSE BRAKE SYSTEM FAILURE! All brake systems get moisture in them, espacially here in Houston, by God, Texas where it is sub-tropical and humid as all get out!!! This includes systems with silicon fluid... I never put silicon in a system because of this... and I'll tell you why. Silicon fluid does not absorb moisture, and moisture is going to get into the system just because it is vented at the cap! Since the fluid doesn't absorb moisture, and the specific gravity of water is higher than that of all brake fluid.... take SWAG (silly wild-ass guess) as to where moisture winds up in a silicon system! YUP! The calipers and wheel cylinders (lowest points). I just last year did a complete restorative brake job on a show(concours winner) 1968 TR250 that had been given the silicon treatment some 2-3 years before. The calipers were so frozen that it took a torch to heat them in order to get the pistons out. The wheel cylinders were just as bad, too. and I got pure water out of both calipers and wheel cylinders upon disassembly that proves my point about where water goes! I converted his car back to DOT 3 and admonished him to flush every 2 years.

 

[sparkydave]

Actually the DOT numbers refer to the number of the DOT specification; it does not refer to the moisture percentage. DOT 3 specifies a minimum wet and dry boiling point (not 3%), DOT 4 specifies a higher boiling point, and DOT 5 is reserved for silicone, which has a much higher boiling point. Long ago there was a DOT 2 specification. Also, there is no such thing as silicon brake fluid. There's a BIG difference between silicon (used as an abrasive) and SILICONE (a slippery substance used as a lubricant) . Silicone fluid was developed for the military, specifically so they could store vehicles for a long time without absorbing moisture from the air; something DOT 3 and DOT 4 do quite well, even through rubber hoses. DOT 5 is immune to absorbing moisture directly from the air; about the only way it's going to get water in it is if you pour water into it, or you get some condensation under the master cylinder cap, which is what I suspect may have happened to that Triumph. There was a very good article on the Vintage Triumph Register citing some data from General Electric (one of the developers of silicone brake fluids) where they took a brake hose, filled it with the various fluids, and immersed the hose in water, measuring the amount of water they absorbed over time. DOT 3 and 4 absorbed lots of water, the DOT 5 had no water in it, not even water droplets, since it repels water.

I converted my Midget 3 years ago, and I keep an eye on it since it does have a vent hole in the cap, but even when we've had big temperature swings I've never seen condensation on the cap. Likewise, the wheel cylinders are still in great shape, and the fluid is still crystal clear. You are correct that water won't mix with it, which has a more serious problem of having a very low boiling point in the wheel cylinders if you get water droplets in it. And you are correct that even the DOT 5 labels admonish against using it in ABS systems, which is why I would never consider converting my daily driver.

Very good post.... The dot "3" "4" "5" number is the indicator in percentage as to how much moisture the brake fluid can absorb before it is saturated beyond safe operating limit.... 3 percent isn't much by volume, either... so 2 years is max. Another point that is EXTREMELY important! NEVER EVER EVER put silicon brake fluid in an ABS unit! IT WILL CAUSE BRAKE SYSTEM FAILURE! All brake systems get moisture in them, espacially here in Houston, by God, Texas where it is sub-tropical and humid as all get out!!! This includes systems with silicon fluid... I never put silicon in a system because of this... and I'll tell you why. Silicon fluid does not absorb moisture, and moisture is going to get into the system just because it is vented at the cap! Since the fluid doesn't absorb moisture, and the specific gravity of water is higher than that of all brake fluid.... take SWAG (silly wild-ass guess) as to where moisture winds up in a silicon system! YUP! The calipers and wheel cylinders (lowest points). I just last year did a complete restorative brake job on a show(concours winner) 1968 TR250 that had been given the silicon treatment some 2-3 years before. The calipers were so frozen that it took a torch to heat them in order to get the pistons out. The wheel cylinders were just as bad, too. and I got pure water out of both calipers and wheel cylinders upon disassembly that proves my point about where water goes! I converted his car back to DOT 3 and admonished him to flush every 2 years.

 

[Guest]

My boo boo on the mis spelling... Vehicle manufacturers tell you not to use siliconE brake fluid in ABS units as well...The TR250 I alluded to had been converted and I'm sure all the old fluid wasn't removed. Regardless, the old GE stuff would off-gas with elevation, and I had more than a couple of Corvettes back in those early days suffer from spongy pedal in the higher elevations but return to normal pedal upon re-entry into lower atmosphere.

 

[Scott_Hower]

VAnother point that is EXTREMELY important! NEVER EVER EVER put <span style="font-weight: bold">silicon</span> brake fluid in an ABS unit! IT WILL CAUSE BRAKE SYSTEM FAILURE! All brake systems get moisture in them, espacially here in Houston, by God, Texas where it is sub-tropical and humid as all get out!!! This includes systems with <span style="font-weight: bold">silicon</span> fluid... I never put <span style="font-weight: bold">silicon</span> in a system because of this...

Psst... it's silicone. Silicon is beach sand.

 

[PAUL161]

I have another truck, a 1991 Ford Ranger which I have owned since day 1. I've never changed it and it has 132,000 miles on it. So maybe it's bunk.

Vince, I also have an old Ford Ranger that I bought new in 1986. 4cyl engine, std transmission. All that was ever done to it was a new clutch at 145,000 miles. It has close to 250,000 miles on it and I'm a little ashamed to say, has never had the fluid changed in the brake system. Of course it's off the road and has only been used around the place for the past 5 years. But, the brakes still work fine! Go figure.

Oh! I forgot to say, with the exception of the timing belt, changed around 90,000 miles, the engine has never been apart and still runs like a dream. Says a lot for Fords little cast iron 4 cylinder, that they discontinued a short time after.