Dot 5 vs. Dot 5.1 Brake Fluid Question! : V-Twin Forum: Harley Davidson Forums

jim_98335 · 06-06-2006, 12:33 AM

This winter I bought a 2003 FLHRCI with 4000 miles on it. This past weekend I decided to bleed the back brake just for something to do. I bled the system manually by pumping the pedal and draining the caliper through a clear tube into a cup.

I refilled the brake reservoir with Dot 5 per the manual before I noticed that the brake fluid in the cup (coming from the caliper) was amber colored like Dot 5.1 instead of purple like the Dot 5. I checked the front brake reservoir and it was filled with amber brake fluid also.

Here are a few questions I have:

Is there such a thing as an amber colored Dot 5 brake fluid that the factory might have used? (The guy I bought the bike from was not a hands-on kind of guy and he said that all the work ever done on the bike was done by the dealer. I believe him. He also was sure that the brakes had not needed work since he bought it new.)

If it was Dot 5.1 how much trouble am I in? (I flushed the system with nearly a whole can of Dot 5 before I put the bike away. The fluid coming out of the caliper was purple most of the time during the bleeding process.)

Finally, how the heck did Dot 5 get into a new bike? (The bike also has a dealer-installed-when-new hydraulic clutch and it has purple fluid in it so I know the dealer had Dot 5 in the shop.) Does the factory or the dealer fill the brake fluid reservoirs?

Thanks in advance for any help or advice you can give me!

DR_DEUCE · 06-06-2006, 01:18 AM

I have never heard of Dot 5.1 fluid. The purple Dot 5 turns amber within a few months.

jim_98335 · 06-06-2006, 01:41 AM

I hadn't heard of Dot 5.1 either, but my Clymer Manual says the following:

WARNING Do not use brake fluid labeled DOT 5.1. This is glycol based fluid that is not compatible with silicone based DOT 5. DOT 5 brake fluid is purple while DOT 5.1 is amber/clear. Do not intermix these two different types of brake fluid. It will lead to brake component damage and possible brake failure.

You can see why I was concerned when I saw my fluid coming out of the caliper a nice amber color.

I didn't know that the purple Dot 5 changes colors. That's the answer to my concern then if it does.

Thanks!

road_king · 06-06-2006, 10:49 AM

Your bike came from the factory with Dot 5 brake fluid.
That does not mean that is what was in the bike when you purchased it.
You do not want to mix Dot 5 with Dot 3, Dot 4 or Dot 5.1.
If this happens, you want to thoroughly flush out the brake system.
Over time, Dot 5 brake fluid can change from the purple tint to a tan color.
The best way to tell what brake fluid you have is to mix some with water. After the solution settles, Dot 5 and water will seperate, where as the others will not.

jim_98335 · 06-07-2006, 03:07 PM

I tried the water test with the amber brake fluid that's in my bike and it balled up just like the purple DOT 5 fluid fresh from the can did, so I guess it must be DOT 5 and not DOT 5.1. Thanks for your help on that.

It sure seems goofy to me that the DOT 5 brake fluid dye would turn the color of an incompatible type of brake fluid while it sits in the bike. Mine was a clear amber color just like DOT 5.1 is supposed to be.

Anyway, I flushed out both brake systems and the hydraulic clutch with new purple DOT 5 brake fluid. I'll see what color it is a few months.

Thanks again for you help.

fxdwg2005 · 06-07-2006, 04:00 PM

lol, do they have a service pack for 5.1 out yet?

Geezer-Glide · 06-07-2006, 04:14 PM

Spill some on your tank. If the paint is there in an hour it's DOT 5 sylicone based.

jim_98335 · 06-09-2006, 11:24 PM

Geezer-Glide

I left the brake fluid I bled out of my rear brake system on the top of the fuel tank for an hour. Fortunately it just wiped off with no damage to the paint. I guess I must be okay assuming that it's DOT 5.

Thanks for the advice!

tibs · 06-10-2006, 12:52 AM

I hope thats a joke...

Some brake fluid will ruin your paint in no time at all. It can also ruin hoses and the such.

Its late, but wow thats just crazy CRAZY stuff.

newultraclassic · 06-10-2006, 11:33 AM

Quote:

Originally Posted by jim_98335

I tried the water test with the amber brake fluid that's in my bike and it balled up just like the purple DOT 5 fluid fresh from the can did, so I guess it must be DOT 5 and not DOT 5.1. Thanks for your help on that.

It sure seems goofy to me that the DOT 5 brake fluid dye would turn the color of an incompatible type of brake fluid while it sits in the bike. Mine was a clear amber color just like DOT 5.1 is supposed to be.

Anyway, I flushed out both brake systems and the hydraulic clutch with new purple DOT 5 brake fluid. I'll see what color it is a few months.

Thanks again for you help.

As mentioned above, DOT 5 turns amber after a while. Color doesn't matter as long as you have the correct stuff.