Brake System Nightmare - 99 4runner ltd 4wd

All the parts you mentioned have rubber grommets/bushings/o-rings and etc., or any combination of them. There is also a proportioning valve and possibly rear anti-lock valve that possibly have rubber in them as well. They are correct, all parts that have rubber need to be replaced if the fluid is contaminated, anything less is "half-assing" it. There are quite a few things that could have contaminated the fluid, the most likely would be moisture or water. Brake fluid is hydroscopic (sp), IOW it will absorb moisture over time and that is why it needs to be changed on a regular basis. Also, brake fluid will usually start to turn milky or cloudy if it's starting to saturate with moisture. It's also possible someone added synthetic, DOT 5, fluid which would contaminate as it isn't compatible with DOT 4. It's also possible anything could have been added. Not trying to second-guess them but, I would get a second estimate or negotiate for a discount on parts prices from the original shop, they may feel sorry for you a little. HTH, Dave

I'll bet somebody was "helping! I'm Helping!", and put motor oil or power steering fluid (or god knows what) in the brake master cylinder reservoir. The only way to tell for sure would be to drain all the brake fluid and send it to a laboratory, and run it through a mass spectrometer to see what the contaminant was - which will cost almost as much as the repairs...

Sorry, when they say 'every rubber component', they speak the truth. They use a special rubber for the seals in all those brake parts that swells and goes bad when petroleum products get inside them. Wheel hoses, axle hoses, caliper and cylinder seals. And they didn't mention the Load Sensing Proportioning Valve (poor man's Rear Antilock) on the rear axle or the Brake Failure Sensing valve.

Replacing pads and shoes is optional, unless they are worn out and need replacing anyway. Rotors or drums need replacement only if they're worn past safe tolerances. It's a good idea to do them while they have the rest of the brake system apart, but these are still optional items you could very easily (and safely) skip for now and save a few bucks.

The power booster assembly should be fine, it doesn't contact the brake fluid unless the seals on the master cylinder have leaked in it.

And even if the power booster goes bad the worst that happens is you lose the power assist - If you can put your back into it and brake hard with both feet this is not a big problem, if you're an 88-pound weakling it could be. ;-P

Actually, after you add it all up that doesn't sound that far out of line.

I said this a few weeks ago to someone else, but it bears repeating

- do you REALLY want to find out what those "Runaway Truck Escape Ramps" are for, and exactly how they work? Or worse, lose your brakes in a bad place that /doesn't/ have a way to save yourself?

Repeat after me: Never Screw Around With The Brakes. They are the one system that Has To Work, Every Time. Or bad stuff happens.

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They're right. My shop has the same policy due to safety and liability concerns. The contaminated fluid can seep into the rubber parts and can't just be flushed out.

end would start to shimmy at higher speeds. The

the calipers weren't releasing. I gave up

told that some time back, something other than brake

in the brake system have started to deteriorate and

were still trying to accelerate causing the shimmy in

rubber in it. This includes all hoses, both calipers,

rotors. This seems excessive to me. Not to mention,

anything, shouldn't I just be able to replace the

That could be done for a quarter of the price. I

overhaul, but is this completely necessary. Thanks.

If your lucky some of the componets might just need new rubber. But I doubt it.

"calipers to hold on while the rear wheeles were still trying to accelerate causing the shimmy in the front end"

One thing that seems odd about this is there is no mention of the rotors condition. I would expect to see rotors that got so hot they were blue and warped (shimmy source maybe) big time. The pads would also be so hot that when you stopped they be pumping out that stinky smoke.

Dan