Harley Davidson Dot4 brake fluid

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Wed 7 Apr 2004 10:17
Harley Davidson Dot4 brake fluid - THe Growler
Got a long w/end ride coming up so today I flushed out the front and rear brakes on my ride with new Dot4 brake fluid (as per da manual), bled them and everything. She's almost 4 years old so about time I guessed. All is fine.

My question is (or are!): is DOT4 hygroscopic like Dot3, can I store unused fluid without it degrading like Dot3 and does it attack paintwork like Dot3? Nothing on the canister suggests a clue. I called my HD tech but he doesn't know either.

Something tells me mech1 might have the answer, he seems to have a good grasp of the nitty-gritty. Pointers appreciated, because this is imported fluid from the USA (Pitt-Penn) and not cheap.


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Wed 7 Apr 2004 10:41
Harley Davidson Dot4 brake fluid - martint123
I think DOT4 is hygroscopic.
It does damage paintwork.
My bottle says all the above plus 'do not shake'.
I won't get into asking why you're importing brake fluid from the U.S. though.......
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Wed 7 Apr 2004 11:02
Harley Davidson Dot4 brake fluid - Sooty Tailpipes
Do you mean DOT5? Why do you import the brake fluid?
DOT 3,4 and 5.1 are all glycol based and have the same properties wrt paint and hygroscopy, DOT5 is Silicone and has a different set of problems.
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Wed 7 Apr 2004 11:14
Harley Davidson Dot4 brake fluid - trancer
It is imported because it has the Harley Davidson brand name on it 8-). That company is a marketing marvel.
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Wed 7 Apr 2004 11:19
Harley Davidson Dot4 brake fluid - Peter D
Dot 3 and 4 have the same restrictions with use ie. water obsorbtion and attacks paint due to the gylcol base. Dot 5 can only be used with appropriate seals all round and MUST not be mixed with non silicon based fluids. If you fill a Dot 4 system with dot5 the seals will swell up.. Regards Peter
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Wed 7 Apr 2004 11:41
Harley Davidson Dot4 brake fluid - THe Growler
Thank you. This is standard Dot4 import but bought from my local auto supermarket. It conforms to all the HD specs in the manual so that is why I bought it. It is not HD branded or even specifically brand-recognised by HD -- merely it meets the maker's specs. Similar local brands are not available, hence the import to the Philippines.

Given it is quite expensive I wondered whether I could keep the remainder a year or two without it degrading. If not I can junk it. Waste not want not etc :=)

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Wed 7 Apr 2004 11:48
Harley Davidson Dot4 brake fluid - Civic8
IIRC dot4 spec has a higher boiling point than dot3 and a shorter shelf/use life.it I think absorbs damp air faster than dot3 and not certain but think it has to be changed more regularly around 18 month intervals max.I could be wrong as I cant remember the full spec?.but you should be able to find it on the www.
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Wed 7 Apr 2004 23:46
Harley Davidson Dot4 brake fluid - Civic8
Something tells me mech1 might have the answer.


I wonder if you meant me or someone else.tell the truth did not look at later line.so answered as I thought/remembered.If was meant for me I dont know it all and don`t pretend to.I answer as or give advice as I think I am able to.nothing more nothing less.ps have a good holiday
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Thu 8 Apr 2004 14:54
Harley Davidson Dot4 brake fluid - doug_523i
Do Harley's have brakes? :-)
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