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BRAKE FLUID / 4.0 / 5.0 / 5.1 what to use ? WHY

Rancid, be careful about mixing...5.0 Brake Fluid is Silicone based all the others are Ethylene Glycol based...! EG is designed to "swell the seals slightly", but the downside is when it starts breaking down, it attracts water AND will harm paint/finishes.

If you have ever mixed the purple 5.0 and any of the amber colored others in the same container you will see them separate and when shaken the purple globules of silicone based fluid never mix and settle out, meaning that it will be very difficult to purge the system once it is contaminated. A full flush and rebuild of the entire system is minimum, but I would just replace everything, brakes are too important, the threat of sudden failure due to sticking or leaky seals is too great.
 
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Why would you want to use brake fluid that is not the recommended type for your machine? Just asking for expensive trouble.
 
It may be that some people dont understand about the different types of brake fluid here in the uk dot 5 is not redily available i have to order from the internet if i go into autosave or halfords and ask for dot 5 ill be handed dot 5.1 because they dont understand the difference
when i got my softail it had glycol based fluid in the front brake and the brake didnt work so had to strip and sort it anyway

Brian
 
One of the problems is the DOT rating system was based on temperature, not media content. Kinda like the oil ratings i.e 20W-50 like system based on viscosity AND temperature...!

When I first heard of 5.1 (actually here on HDT from Glider, suprisingly enough) I looked into it and was shocked that they would assign that number...as if it was just a revision change like software, not even denoting incompatibility. Silly, well it really isn't, just dangerous and negligent. Wonder what the safety organizations like NHTSA or DOT is going to do about it before someone gets killed over this (likely has happened already)...?
 
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