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Discussion Starter · #1 · (Edited)
I have been using Avid Juicy 7's for almost about 18 months without any problems but on my last 3 or 4 rides the rear pads tend to drag after long downhill sections (read lots of braking). I guess that the fluid heats up and therefore expands after lots of braking but I never had the dragging problem before. Once the brakes cool a bit they stop dragging again. The fluid is original (18 months old) so I am wondering if it needs to be changed? What is the life of disk brake fluid? What else could be causing the brakes to drag when hot?
 

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It's fluid expansion. Flush the system out and bleed with DOT 5.1 for better piston response and higher boiling point. DOT fluid is hydrophillic and absorbs water. The wet boiling point is signifcantly lower.
 

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Discussion Starter · #5 ·
XSL_WiLL said:
It's fluid expansion. Flush the system out and bleed with DOT 5.1 for better piston response and higher boiling point. DOT fluid is hydrophillic and absorbs water. The wet boiling point is signifcantly lower.
Kind of what I figured. DOT 5.1 must be the good stuff, can I get it a Checker, Autozone etc ?

By the way I love your atavar (sp?)
 

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Autozone didn't have it when I checked. They only had the silicone stuff, which is crap. Highly compressible and probably none too good for your seals. I had to order my bottle of Motul online. Cost something like 13 bucks with express shipping.
 

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Discussion Starter · #9 ·
XSL_WiLL said:
Autozone didn't have it when I checked. They only had the silicone stuff, which is crap. Highly compressible and probably none too good for your seals. I had to order my bottle of Motul online. Cost something like 13 bucks with express shipping.
I looked locally - 2 auto and 2 motor cycle shops and could not find DOT 5.1 so ended up ordering the Motul online. I'll let you know if it fixes my problem.
 

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Remember that if you overfill the system, it may not be able to compensate for fluid expansion. I assume that's why Avid has you bleed the brake with the knob all the way in the out position. And I find that sometimes, the system is still overfilled.
 

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Discussion Starter · #11 ·
XSL_WiLL said:
It's fluid expansion. Flush the system out and bleed with DOT 5.1 for better piston response and higher boiling point. DOT fluid is hydrophillic and absorbs water. The wet boiling point is signifcantly lower.
Cheers XSL. I flushed the system and replaced with Motul 5.1. Not only has the drag disappeared when the brakes are hot but the modulation has improved as well.:D
 
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