I have a 97 FLHT, went to add some brake fluid to the front.


Book says DOT 5,, on the master cylinder cap, it clearly says DOT 4.


Which is it?


How can I tell what is in there now?


Will they mix, if I get it wrong??


Thanks


Bike is fairly new to me.

 

Scoop/suck a little out and put it into a glass. Add a drop or two of water. If the water mixes, it's DOT 3/4 glycol. If the water sits on the bottom, it's DOT 5 silicone.

 

That worked great, turns out it's DOT 5, good thing I checked the book.


Thanks a lot.

 

Nice tip!

Shane

 

My 05 uses dot 5

 

dot 5 is purple when new and blackish when dirty. dot 3/4 looks like vegetable oil and is way dark when dirty but still looks like oil but darker. Never tried the water test, dont know if Id trust that especially after someone may have mixed the stuff in years past.

 

I guess these folks are shootin blanks too then.
http://www.belray.com/how-determine-...luid-your-bike

 

perhaps if a system was 100% one fluid like belray is probably talking a out is one thing. But ive seen mixed fluids that i couldnt tell what was what. Ive seen the piston chambers look like they were packed in grease. Im sure the op has a used bike that someone hacked on

 

DOT 3/4/5.1 are all glycols and will not mix with the DOT 5 silicone fluid. Can't remember which lays on top, but they do not mix.

Don't go by color for DOT 5. While it frequently is died purple, it is not inherently purple. Buy it from DuPont and it will be honey colored. I think Harley uses a non-died DOT 5 as well. That purple die also leaches out rather easily.