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.

[76shuvlinoff]

 

[flhs90]

Shovels:

I purchased a 4th hand FLHS 1990 model.
When I was changing my rear caliper pads and cleaning the caliper I noticed someone had changed or "added" a Dot 3 or 4.
I knew from what was in the front brake system (red Dot 5) and my manual that one of the previous owners had put in the "wrong fluid."

Anyway, I pulled the piston, cleaned it and the caliper, put new pads on and put it all back together, then bled the caliper.
Rear brakes just fine. The system does not appear to have gel in the master or the lines or the rear mc and or caliper.

I think I'll be fine. I plan to ride it until the next time I go back in there.

Is it possible someone ahead of me flushed the system like you are mentioning in this thread because the rear system seems just fine.

Murphy's law dictates if it ain't broken don't mess with it. Next time in I'll flush it. Have put 5000 miles on the rears with no issues other than replacing the pads.

Just wanting to be safe.

FLHS 90

[motorplex88]

I don't know that there is a "wrong fluid" per say, just so long as the types are not mixed. If you got 5000 mi. on the work you did I'd say your fine. I think that's how alot of trouble gets started because a person may not know what the last owner has changed around so you gotta start fresh for peace of mind.

[flhs90]

Motorplex 88:


That's what I was thinking. The Dot 5 and Dot 4 were not mixed, just changed from dot 5 to 4/3.
Go figure why they did that.
Beat's me.

I'm collecting the parts, denatured alcohol, etc. when I go back in there. Of course, I'll care the parts in one of the bagger's bags, just in case I'm on a long road trip.

Thanks for the 2 cents.

flhs 90

[jerite]

gents-
is ethyl alcohol the same as denaturated?? They have ethyl here at the local walgreens.
Thanks in advance...
Jer

[ramcr913]

Jerite,
I don't know if it's the same but suspect it is not. Not sure why you would want to use ethyl, since denatured is easy to get. Home Depot and Lowes carry it, it generally comes in one of those flat rectangular cans. I wouldn't use the ethyl.

[jerite]

He ya'all-
I found denatured alcohol at menards. Do I flush that thru the caliper as well or just thru mc and line?
Thanx in advance-
Jer

[76shuvlinoff]

  I am not sure if you HAVE to take the caliper apart but I did to make sure I got rid of all the dot 3 before I went to dot 5,  I was rebuilding them anyhow so it was not a big deal.

[jerite]

I had em' apart, inspected and put on new pads, but I have not ran any fluid thru them yet. So I should be able to flush line and mc I suppose eh?
Thanx-
Jer

[76shuvlinoff]

Jer, nobody wants to give advice on a brake system that might very well bite YOU in the ass.  The reason being is I have heard mixing 3 and 5 can result in locked up or no brakes.

So here's what I did, YMMV.

I had mine apart ( calipers and m/c), cleaned everything with brake clean and rinsed with the denatured alcohol. Then I ran the alcohol through the m/c and lines. Then I ran some dot 5 thru m/c and line before I hooked the line to the caliper. Hooked em up and pumped it through the caliper , bled as usual. For me that means pushing fluid through the caliper via the bleeder valve up to the m/c with a large syringe and tubing if I can't get them to pump up normally.  This initial cleaning and changeover will cost you more dot 5 than a usual bleed.

Good luck bud
     Mark

[ramcr913]

Home Depot and Lowes should have plenty of denatured alcohol, that's where I get it.

[jerite]

hey all-
flushed system out with denatured alcohol, worked great! Thanks for the xcellent advice!!!
Jer

[76shuvlinoff]