Boiled the Brake Fluid, but why?

[polvadis]

I had a complete brake system flush a couple of months ago and of course replaced with a brand new fluid. I also had new rotors and pads put in at the same time.

While slow driving through the mountains the past weekend I first noticed a funky smell and then the pedal dropped way down to the floor. I'm being told that's what a boiled fluid feels like.

So my only questions is; why did this happen? One of the answers is that I rode the brakes too hard. Sure. But should this happen anyway?

I'm being told now to replace the boiled fluid since it has lost some properties through overheating. This stinks since I just did it a couple months ago...

Any ideas on what I should do? Go back to the mechanic that did the brake flush and ask WTF?

Thanks for any info.
-Slav.

 

[polvadis]

To follow up on my own post, I called my mechanic and told him of the problem and he gave me even more confusing info.

He's saying that it's extremely difficult to overheat the brake fluid since the fluid never touches any metal.

However, if that was the case, he's saying that perhaps there's another reason for the overheating like a faulty master cylinder. He's willing to replace the fluid for free but at the same time saying it's gonna happen again if the problem is not fixed with the brakes.

I'm really confused now.

 

[techno]

Yep, riding the brakes too much will produce enough heat in all the brake components to cause the fluid to boil. It happens more than you might think, particularly on heavy vehicles with auto transmissions during extended downhill driving, and even more so when towing. Have you seen the run-away truck ramps they sometimes have in hilly places with long steep descents? They are there for exactly this reason.
I was in a 75 Series LandCruiser Troopy when this happened once. We had the funky smell too, but that was after the brakes failed, if you know what I mean. The driver started downshifting immediately and applied the handbrake a little and he managed to keep our speed down at a controllable rate. We never replaced the fluid after that and didn't have any issues. The Troopy had two of us on board, a months worth of camping stuff, a boat on the roof and a heap of aftermarket accessories.

It could be worth having your mechanic inspect the brakes to make sure everything is still good. Maybe the pads were dragging more than they should. Have you driven through those mountains before?

 

[shootmymime]

why dont u use a lower gear to help your engine keep you at a safe speed, like take overdrive off?


wow thats pretty cool that could happen, but good thing your alright

 

[jeremy9allen]

There are a few things that are pretty common that can cause this too.

One would be seized caliper pins not letting the brakes un apply as they should. You would probably smell the pads burning first though.

Another problem is how the brake fluid was stored before it was put in your system. Brake fluid is hydroscopic, meaning it will absorb moisture out of the air.
If a cap is left off the bottle for an extended period of time, there could be enough moisture in the fluid to let it boil at a low temperature.

I think synthetic fluid is supposed to have a higher boiling point than the dot3.

You may want to use the synthetic.

 

[Tomsriv]

I agree with the above post. The fluid may have been bad from having the cap left off, or half an old bottle was used to fill your truck. I also agree that you should use a lower gear. Take the OD off, if that is to fast switch to "2", if that is still to fast go to "L". At low speeds in L you probably won't build up to much heat.
I have never lost my brakes, but I have warped the rotors a couple times on my 4runner. You could almost call it a design flaw, these runners do not have HD enough brakes.
As far as synthetic, you have to flush everything to get it in there or else it will get contaminated. I put it in my '65 chevy truck after I replaced the whole brake system, lines and all, and put on 4wheel disc brakes.