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Old 03-11-2012, 11:21 AM
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Originally Posted by malc
I was at a friends garage today and we were looking at his 3rd Gen Pontiacs motor.
As he is a tech guy at VWs sister firm here Seat, I asked him why the coiled brake pipes, as per his Pontiacs master cylinder/proportioning valve.
He told me it was to curb vibration and as a cooling aid for the pipes which were for the front discs, the rear connection does not have this.
The idea is, the front brakes, which are close, get hot and can heat the fluid up to the brake proportioning valve, if the line were just straight and 90 the heat could cause it to buckle, so the coil takes it better without distortion.
He also added that he has seen coils off the rear discs as well to dissipate heat without distortion to the brake line there.
No offense intended, Malc, but the "distortion to the brake lines" theory doesn't hold a whole lot of water with me.

Here are the Dry boiling point and Wet (3.7% water) boiling point for brake fluids:

DOT 3: 205 C (401 F) / 140 C (284 F)

DOT 4: 230 C (446 F) / 155 C (311 F)

DOT 5: 260 C (500 F) / 180 C (356 F)

DOT 5.1: 270 C (518 F) / 190 C (374 F)

I will concede that steel (alloys) DO begin to lose strength at much lower temperatures than their approximate melting point of 1,370C (2500F) , as made evident by the collapse of the World Trade Center.

"Steel can be soft at 538C (1,000F) well below the burning temperature of jet fuel."
The "tongue-in-cheek" or "I heard" remarks that inevitably work their way into conversations like this can be taken (and quoted) as fact.
(The good old "If I read it on the internet, it has to be true." syndrome. Discuss this phenomenon with your favorite Mechanic, Partsman, or Doctor.)
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