pretty much true. Dont run DOT 5 unless you are told to by the manual. And if you are supposed to use DOT 5, dont switch to DOT 4 or DOT 5.1.

Technically, with a proper cleaning, all masters will work with either fluid. DOT 3/4/5.1 are what are called glycol fluids. DOT 5 is silicone. When mixed together, the glycol and silicone can damage, or even destroy your brake system.

If your brake system says to run DOT 4, you can run DOT 3(not recommended because of lower boiling temperature), DOT 4, or DOT 5.1(extremely high boiling temperature and used in race vehicles that get the rotors glowing red) without having to do anything major to your system. If you completely drained and cleaned the system(res, master, lines, and calipers), you could use DOT 5.

If your system instructs DOT 5, you can ONLY run DOT 5 without needing to do all the cleaning and draining.

I would recommend you just use whatever the manual tells you to use.

 

thats why the diaphragm is there. But if you fill the res past the full line, you will either:
A) have brake fluid come out because there isnt enough room for the diapragm
B) have the diaphragm leave just enough space
C) have the diaphragm be squished to smaller than its needed size, which doesnt allow enough room for the expanding heated brake fluid.

 

So wats the best way to clean ur system and, change fluids, without mixing them together? I run dot 5, and its been giving me hell lately, but ppl tell me not to mix them 2gether, I just want to change fluids and go back to dot 4 or 5.1!!! Please advice

 

I wasnt really sure on this, so i called a friend who is a mechanic at a local car shop

take off your calipers and master. Take them apart and check/clean the seals. If the seals dont look like they are in very good condition, replace them. now run denatured alcohol through your lines. after you do this, put it back together and run a lot of denatured alcohol through the system(basically act like you are bleeding the brakes, except use denatured alcohol. Then after you get done running a bottle or two through the system, pump the lever until no more alcohol comes out. not start putting in the brake fluid of your choice. I would bleed at least one bottle through, and then use the second one for the actual brakes. Just be sure not to spill any brake fluid on your paint, or be ready to see the paint get destroyed on the spots where that fluid touched.

 

snotrocket boiled his fluid 20minutes ago when we were riding. alllllmost looped his ****.