ZEE Brakes - mineral oil being bolied?

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ZEE Brakes - mineral oil being bolied?
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flag ciechan
O+
Posted: Feb 2, 2016 at 1:19 Quote
Hi guys,

I have an issue with my ZEE brakes.

Usually they are perfectly bleeded, the lever is super-consistent, everything is just fine.

However in last 2 months it happened twice where the rear brake lever just started going all the way to handle bar. I had to pump it twice and then the brake was working. I tried again after 3 seconds and same. All the time.Typical sign of bleeding need! I left the bike for 30mins and it was stop-on again! No issues or whatsoever! Lever was again consistent. I continued racing all day and it was perfect.

It happened after my race run. I bleeded the brake after the race (although it was working perfectly after all) and there were no bubbles at all. What is the root cause of that? Is that overheating? I couldn't however smell the pads burning.

Thanks
flag JonProce
Posted: Feb 5, 2016 at 6:12 Quote
Wouldn't be the mineral oil boiling, but rather water trapped somewhere in the system. People generally have a hate-on for Avid and SRAM brakes with their DOT5.1 fluid, but DOT fluid is formulated to absorb water, whereas mineral oil won't mix with it at all. While it's cold water will act like hydraulic fluid, but once it boils even a tiny amount will expand into a large volume of gas and screw with your brakes in the way you described. Bleed/flush!
flag ciechan
O+
Posted: Feb 5, 2016 at 6:58 Quote
Makes sense, thanks a lot! Any tidy way of flushing the system?
flag JonProce
Posted: Feb 5, 2016 at 7:37 Quote
Standard bleed process should do it. Just push half or 3/4 a syringe of fluid up from the caliper through the system.
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