Brake Fluid

[jerite]

hey guys-
Are ya'all still just runnin' dot 3 in the older disk brake set ups?
jer

[motorplex88]

Dot 3 rear, dot 5 front. Don't ask why, it just ended up that way.

[ramcr913]

The 1978-1984 FL/FX HD service manual specifies Dot 5. I wouldn't use Dot 3 in either the front or the rear.

[HarleyCharley]

Dot 5 only. More expensive but won't screw up paint!  

charley

[jerite]

Ram-
I thought thats what my manual said, but I forgot to look this morn before i left and I need to pick some up on my way home and did not want to go back out, too friggin cold.
Thanks-
jer

[buzzurd]

Is dot4 compatible with dot5?
Buzzurd

[FSG]

Is dot4 compatible with dot5?
Buzzurd

NO

[motorplex88]

I don't pretend to know the exact specifics of brake fluid but I never mix them cause the boiling point and moisture absorbtion are all different between the three. If mixed they will seperate and sometimes even gel making your problems even worse. [yeah, I did it once, what a mistake  ]

[stroker800]

 Dot 3 &4 are compatable ,,4 will take higher heat,,,but they will eat paint.
Dot 5 is a silicone based fluid,,won't harm paint but won't take the heat like Dot 4.
You can run any of the above in a new system,,,if you want to change over one to another you must flush the entire systm with denatured alcohol,,I would suggest a few times.
Dave

[ramcr913]

Stroker800 is correct. 3 & 4 are compatible. Dot 5 is easy on paint.One last note- Dot 5 is not compatible with any other fluid.

[Old Crow]

You also need to keep Dot 5 away from any area where you might be painting.
Most paints don't like silicone.

[FSG]

and lets not forget DOT 5.1 (5 point 1) which is in the same family as DOT 3 & 4

BUT it is NOT compatible with DOT 5 which a lot of folk find out the hard way after some autoparts store sells them a bottle saying it is.

[76shuvlinoff]

To avoid any confusion I only run dot 5, even used on the old nanners when I had them. If you have the system apart for a rebuild it's a perfect time to purge, clean and convert.  Denatured alcohol works for cleaning.

Mark

[jerite]

With the alcohol what do you do pump all the existing almost gone then add alcohol until its flushed then pump that almost gone flush and fill with new?
Jer

[GaryD]

Sir Garfield is absolutely right. And lots of people think they can mix them because they have the same number. I don't know why they just didn't give the new stuff an entirely different number to avoid the confusion. Computoreze is creeping into everything now, DOT 5.1 --- give me a break --- just say DOT 6.

[76shuvlinoff]

Jerite
When I did it I flushed it through like you described then disassembled the nanners and made sure they were clean. I was rebuilding them anyhow so it was time for new seals.

Mark

[jerite]

Thanks Mark!

[randallwhitman]

Just a somewhat goofy thought.  On the way to Sturgis, my buddy had a brake line leak.  DOT 5 is impossible to find in the boonies.  Basically, only bike shops sell the stuff.

[76shuvlinoff]

 randall I can't debate that statement except to say I get mine off the shelf at the NAPA auto supply in my corn country hometown, population 800-900 tops.  Maybe that ain't the boonies..... but I have always thought it was.  If I ever get to do another road trip maybe I ought to toss a bottle of dot 5 in the bags.

  - Mark

[GaryD]

I also bought a can of Dot 5 at a NAPA store in Williston, ND on my way to the HOG ralley in Saskatoon when my braided front brake line sprung a leak between the steel braid and the clear outer cover. They even let me use a pillips screw driver because I didn't want to dig to the bottom of my saddlebag to get mine.
I was really shocked they had Dot 5 on the shelf in a town in the middle of nowhere.
Mark, that's not a bad idea about carrying a bottle with you. I use to carry a can of oil, but never had to use it, so maybe I'll substitute a can of Dot 5 instead.

[jerite]

HELP!!!
I cant find that denaturated alcohol anywhere...suggestions where or a substitue to flush with?
thanx in advance-
Jer

[motorplex88]

I would think any drug store or store that sells drug store items would have some. I've even seen it offered at parts stores just for this reason. In a pinch I have used aerosol brake clean but tear down each brake component,clean sepreatly, blow dry and reassemble dry, using brake fluid at o-ring and seal areas for assembly.

[76shuvlinoff]

I've seen it used to clean jewelry.
I would think a paint supply or hardware store would have it.


I got mine from work, sorry.  Probably ordered from MSC or McMaster Carr.

[jerite]

Do you just pour the alcohol in and flush it thru I assume correct???
Thanx in advance...
Jer

[motorplex88]

If your just flushing the system then yes. I use some type of suction bulb to pull out brake fluid from the reservoir, then add the alcohol and bleed normally till completly clear and clean. The system will pump up but won't have the same feel as brake fluid. Then go back wilth brake fluid. If your changing fluid types I highly recommend tearing down the complete system, clean with alcohol, and reassemble. If rubber lines are in place it is also a good time to inspect along with seals in calipers. I'm sure others will have other opinions and proceedures just as good.