DOT4 Brake Fluid after 1 Year
Thread Starter
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Stellar HDF Member
Joined: Nov 2008
Posts: 2,432
Likes: 290
From: FL
If you're opening your M/C, on a daily basis, it's no wonder you are showing a high water value, as the fluid is hygroscopic.
EDIT~ One other thing, your fluid is dark. This tells us it has oxidized too. Best to change/flush that fluid before your ABS unit fails. (It doesn't take much oxidation for this to happen.)
EDIT~ One other thing, your fluid is dark. This tells us it has oxidized too. Best to change/flush that fluid before your ABS unit fails. (It doesn't take much oxidation for this to happen.)
Banned
Joined: Jun 2019
Posts: 78
Likes: 19
From: Lititz Pa
Thanks I have them all don't why
Quick background...
DOT 3, 4, & 5.1 brake fluids are glycol based. They readily absorb water and will damage paint. They are cross-compatible. DOT 3 & 4 are used everywhere and DOT 5.1 is a higher performance version of 3 & 4.
DOT 5 brake fluid is silicone base. It doesn't absorb water and will not damage paint. It is NOT compatible with DOT 3, 4, or 5.1 glycol based fluids
DOT 5 brake fluid has higher wet and dry boiling points than glycol based fluids (with the possible exception of some DOT 5.1), and is generally considered a better brake fluid than the glycol based DOT 3 & 4 fluids.
Why does everybody still use glycol based brake fluid?? I'll skip the technical explanation, but in a nutshell, silicone based DOT 5 brake fluid does NOT play well with ABS brakes....
If you want ABS brakes, you can't use DOT 5 silicone based brake fluid...
My older twin cams both use DOT 5. I forget when Harley started using DOT 5, but I think even my shovel heads may have used it. They switched to DOT 4 in 2005ish, when they first started offering ABS brakes as an option on a few models, to avoid any brake fluid confusion with a given model year of bikes...
Sorry if too much info, but you asked.....[/QUOTE]
Quick background...
DOT 3, 4, & 5.1 brake fluids are glycol based. They readily absorb water and will damage paint. They are cross-compatible. DOT 3 & 4 are used everywhere and DOT 5.1 is a higher performance version of 3 & 4.
DOT 5 brake fluid is silicone base. It doesn't absorb water and will not damage paint. It is NOT compatible with DOT 3, 4, or 5.1 glycol based fluids
DOT 5 brake fluid has higher wet and dry boiling points than glycol based fluids (with the possible exception of some DOT 5.1), and is generally considered a better brake fluid than the glycol based DOT 3 & 4 fluids.
Why does everybody still use glycol based brake fluid?? I'll skip the technical explanation, but in a nutshell, silicone based DOT 5 brake fluid does NOT play well with ABS brakes....
If you want ABS brakes, you can't use DOT 5 silicone based brake fluid...
My older twin cams both use DOT 5. I forget when Harley started using DOT 5, but I think even my shovel heads may have used it. They switched to DOT 4 in 2005ish, when they first started offering ABS brakes as an option on a few models, to avoid any brake fluid confusion with a given model year of bikes...
Sorry if too much info, but you asked.....[/QUOTE]
Club Member
Joined: Aug 2008
Posts: 21,763
Likes: 22,964
From: North Carolina
I just watched a really good YouTube video last night on this. Looks like it can easily be done at home as long as you dont introduce air. Mine is coming up on two years now. Plan to do it soon.
I assume that when the dealer did my clutch recall that the clutch fluid was changed / purged? Anyone know for sure if that happens during that procedure?
Thanks
I assume that when the dealer did my clutch recall that the clutch fluid was changed / purged? Anyone know for sure if that happens during that procedure?
Thanks
Thread Starter
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Stellar HDF Member
Joined: Nov 2008
Posts: 2,432
Likes: 290
From: FL
I just watched a really good YouTube video last night on this. Looks like it can easily be done at home as long as you dont introduce air. Mine is coming up on two years now. Plan to do it soon.
I assume that when the dealer did my clutch recall that the clutch fluid was changed / purged? Anyone know for sure if that happens during that procedure?
Thanks
I assume that when the dealer did my clutch recall that the clutch fluid was changed / purged? Anyone know for sure if that happens during that procedure?
Thanks
Seasoned HDF Member
Joined: Apr 2015
Posts: 10,068
Likes: 5,320
I just watched a really good YouTube video last night on this. Looks like it can easily be done at home as long as you dont introduce air. Mine is coming up on two years now. Plan to do it soon.
I assume that when the dealer did my clutch recall that the clutch fluid was changed / purged? Anyone know for sure if that happens during that procedure?
Thanks
I assume that when the dealer did my clutch recall that the clutch fluid was changed / purged? Anyone know for sure if that happens during that procedure?
Thanks
Thread Starter
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Stellar HDF Member
Joined: Nov 2008
Posts: 2,432
Likes: 290
From: FL
Preventative maintenance is the best type! Glad I could help. Just got back from Virginia earlier today. Weather sure was nice up there. One day Im moving!
Former Sponsor
Joined: Jan 2019
Posts: 162
Likes: 16
From: WA
The pictures in this thread are why I tell my customers to consider an annual flush routine. It's 30 minutes in the garage in the winter. Worth it for your safety and your bike's health.
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Seasoned HDF Member
Joined: Mar 2010
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From: Honah Lee
Just out of curiosity, did you calibrate it from a sealed bottle of DOT 4?
The system is sealed. The diaphragm in the master is how it works. Not sure how it could have got that much moisture unless it started with a lot.
If you don't have a moisture checker. You can use your Volt/Ohm meter set high on 10 Meg ohm reading. Put the two probes into the fluid. Takes a few minutes but if it moves up past 5 MG ohm resistance, there is little moisture.
The system is sealed. The diaphragm in the master is how it works. Not sure how it could have got that much moisture unless it started with a lot.
If you don't have a moisture checker. You can use your Volt/Ohm meter set high on 10 Meg ohm reading. Put the two probes into the fluid. Takes a few minutes but if it moves up past 5 MG ohm resistance, there is little moisture.
Last edited by Jackie Paper; Jul 2, 2019 at 11:42 AM.