I did a mistake to put DOT 5 to my 2008 Low rider rear brake system, I found the brake loss the braking power soon after breeding it, do I need to replace the whole thing?
Or I just clean it and put DOT4 again will back to normal?

 

I was always under the impression if you went up in numbers (not down like DOT 3) that you would be ok. Have you tried bleeding it?

 

also note that dot 4 and 5 shouldn't ever be mixed. Personally I would clean/flush it an go back to dot 4

 

its has been couple months using the DOT5, I'm afraid some damage done to the system, will change to DOT4 soon!

 

DOT4 absorbs moisture. DOT 5 is silicon based and does not absorb, if there was any moisture in the system it will puddle. You may have a problem with corrosion.

 

just flush it out, no biggy

 

You should bleed it and not breed it, that way it won't be fu&ked.

Seriously just flush it out, refill, bleed and fill it with the correct stuff and hopefully that will take care of it.

 

Sorry, my bad English!!
I read somewhere from this forum, DOT5 harm Brembo brakes seal!

 

DOT 5 Silicone fluid cannot be mixed with any other type. If the system is not completely purged before conversion, the mixture may gel and result in very poor braking. Therefore conversion usually requires disassembly and a thorough cleaning, or at least numerous bleeding sessions over several days.

 

This is not quite right. DOT 4 is an improved DOT 3 with a higher boiling point and they are quite compatible. DOT 5 is a totally different product and is not compatible with any other brake fluid. (It would be like mixing water and oil)
The confusing part is there is an improved formula of DOT 4 with an even higher boiling point that is named DOT 5.1. So DOT 3, 4, and 5.1 are compatible.