Brake flush for 2008 dyna and 2004 FLH

[ndmp40]

Both bikes badly need flushing and replacement fluid.  Should I use DOT 3 or 4?   Can you mix the two?
Thanks for the advice in advance.

[kd]

What does it call for in the service or owner manual?

[Hossamania]

Dot4 and Dot5 cannot be mixed, I cannot say for sure that dot4 and dot3 cannot be mixed, but I'm 99% sure they cannot. I believe those use dot4, check your manual, get a new container of fluid.

[Rusticwater]

For your reading pleasure: link

FWIW the 2008 Dyna FSM specifies DOT 4.

[Coyote]

It should say on your mc lid but I believe the flh will be dot5  and the other bike dot4. Do not mix them.

[Norton Commando]

I've mixed DOT 3 and 4 fluids more than once an experienced no ill effects.

Jason

[Coyote]

3 and 4 will mix but 4 has a higher boiling point. Why degrade it with Dot 3.

[Dan89flstc]

2004 model year bike uses DOT 5.

2008 model year bike uses DOT 4.

[Buglet]

  Check what the lid says. Some 2004's and 2005's some came with Dot 4 and some with Dot 5. I think 2006 they finally went all to Dot 4.

[HogMike]

DOT 3,4,5.1 are all similar glycol based.
Difference is boiling points.

DOT 5 is the odd duck and can't mix with the others, as it is silicone based.

My 2000 is dot 5, my other bikes are DOT4.
You can buy a bottle of DOT3-4 at the parts store and it will work.

Lots of info on the net.

[kd]

all of the above is the reason I asked what fluid was actually specified.  Simply replacing with another type can be problematic especially if they contradict each other. Even a complete "flush" can miss residue or pockets that may negatively effect the brakes un-expectantly at a later date. If I was changing grades I would be inclined to consider some disassembly for deep cleaning first.

[ndmp40]

Thanks for the help.
Going by what is listed on the bike caps is not constructive as the bikes were used when I bought them and have been worked on several different shops over the years. 

[Coyote]

See what color the fluid is.

[smoserx1]

The only thing I know Harley has used since 1999 is Dot 5 and Dot 4.  The switch to Dot 4 was because of ABS.  Anyway if you have a small syringe or baster draw a small amount out of the reservoir and see if it will mix with water.  Dot 5 will not mix at all, since it is an oil, but the others will.  Dot 5 is supposed to be purple in the container.  I have had some that was so light you could barely tell, but every bit of it I have ever used turned tennis ball yellow/green within days after changing it in my system.  Any Dot 3 I have ever had would turn almost black in short order from absorbing moisture.  Dot 5 will not absorb moisture, all the others will and they have to be changed regularly.  Most Dot 3 is light amber when new but I purchased a can of it back in the 70's that was dark green out of the can.  Go figure.

[Dan89flstc]

Harley used DOT 5 from the mid`70s through 2005.

When the anti lock systems came out in `06, they also specified DOT 4 in all the bikes, just so there was no mix up.

Color of fluid in the bike doesn`t tell you enough to determine what is in there.

[Norton Commando]

Harley used DOT 5 from the mid`70s through 2005.

When the anti lock systems came out in `06, they also specified DOT 4 in all the bikes, just so there was no mix up.

Color of fluid in the bike doesn`t tell you enough to determine what is in there.