DOT4 Brake Fluid after 1 Year
Road Warrior
Joined: Sep 2014
Posts: 1,271
Likes: 246
From: Columbia SC
To me, by looks the brown fluid isnt that bad, normally much more black in color after two years.
Good post, for me Ill just keep following the manual of 2 years but you have a solid case along the coast.
Even some automobile manufacturers recommend every two year but for some reason the public including bikers think brake fluid is forever.
I was one of them when I lost the rear brakes on my previous bike, a Yamaha Vstar 1300, I was at the top of a mountain road, coming down a mountain with luggage and my wife on the back., longest 10 minutes of my life, lost rear brake, didnt know what was going on, no place to pull off, narrow road, not knowing if the front would go out too, back brake petal non responsive, got to the bottom of the mountain and thought to myself thank god, then though to myself vacation will be ruined, here I was in the middle of the Smoky Mountains, 10 minutes later the rear brake started working again, learned it was vapor lock from moisture in the system.
For some reason, for all models, the brake fluid change requirement on motorcycles is always buried someplace in the maintenance manual, you would think that being a life and death issue it would be in the same place as oil change requirement.
)
One thing for sure, you also will extend the life of brake system components or better said, avoid them going bad.
Its got to be the most neglected thing on bikes, trucks and automobiles = Click here
Good post, for me Ill just keep following the manual of 2 years but you have a solid case along the coast.
Even some automobile manufacturers recommend every two year but for some reason the public including bikers think brake fluid is forever.
I was one of them when I lost the rear brakes on my previous bike, a Yamaha Vstar 1300, I was at the top of a mountain road, coming down a mountain with luggage and my wife on the back., longest 10 minutes of my life, lost rear brake, didnt know what was going on, no place to pull off, narrow road, not knowing if the front would go out too, back brake petal non responsive, got to the bottom of the mountain and thought to myself thank god, then though to myself vacation will be ruined, here I was in the middle of the Smoky Mountains, 10 minutes later the rear brake started working again, learned it was vapor lock from moisture in the system.
For some reason, for all models, the brake fluid change requirement on motorcycles is always buried someplace in the maintenance manual, you would think that being a life and death issue it would be in the same place as oil change requirement.
)One thing for sure, you also will extend the life of brake system components or better said, avoid them going bad.
Its got to be the most neglected thing on bikes, trucks and automobiles = Click here
Last edited by alarmdoug; Jun 25, 2019 at 05:46 AM.
Banned
Joined: Jun 2019
Posts: 78
Likes: 19
From: Lititz Pa
I do keep up with maintenance of my bikes all the time. Just would like to know why dot 4 why not use some other like DOT 5 or 3. I know the easy answer not compatible. Why make a break system that uses the other fluid. Can someone explain to me why.
Road Master
Joined: Aug 2007
Posts: 809
Likes: 570
From: Detroit Metro Area
I checked mine during Spring commissioning this year. 1.2 years since purchase in Dec 2017 and it registered <1% on the meter with 5500 miles on the clock. I flushed my BMW last Winter as it popped at 3% but I had not changed it in the 6 years I owned that bike. By Dec 2019 it will be 2 years since purchase but I am not anticipating that it will be at the 3% yet. I keep a watch on it.
As a frame of reference, my bike is garaged and I live next to a lake so it is pretty humid all year round. However, the bikes are in a heated garage and that may make a big difference as there is no heat/cool cycle in cooler to cold weather that may cause condensation.
As a frame of reference, my bike is garaged and I live next to a lake so it is pretty humid all year round. However, the bikes are in a heated garage and that may make a big difference as there is no heat/cool cycle in cooler to cold weather that may cause condensation.
Road Warrior
Joined: Sep 2014
Posts: 1,271
Likes: 246
From: Columbia SC
4 is an improvement on 3, higher boiling point, 5 is a older special applications only fluid made of silicon or something and Only for use in those more rare systems.
Just follow the recommended fluid.
Just follow the recommended fluid.
Last edited by alarmdoug; Jun 25, 2019 at 07:26 AM.
Seasoned HDF Member
Joined: Apr 2015
Posts: 10,070
Likes: 5,321
Speaking of moisture in brake fluid, I've noticed that whenever I've removed the reservoir covers (front and rear) that the gaskets have been sucked down into the reservoir. I know this is normal since the fluid level drops as the pads wear down. When I changed my worn brake pads earlier this month, both reservoir gaskets had been sucked so low in the reservoir that they were actually sitting in the remaining fluid in the reservoir. Wouldn't this mean that the reservoir has negative pressure (vacuum) and that air (moisture) might be entering through leaks in the reservoir cover? I know they say that moisture enters through microscopic pores in the brake lines and seams in the brake system and, because DOT 4 brake fluid is hygroscopic, that's where moisture gets into the fluid. However, I'm thinking more moisture gets in through the cover. What do y'all say?
Seasoned HDF Member
Joined: Jan 2015
Posts: 16,021
Likes: 7,147
From: Sandy Eggo's North County
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.)
Last edited by NORTY FLATZ; Jun 25, 2019 at 08:33 AM.
Seasoned HDF Member
Joined: Apr 2015
Posts: 10,070
Likes: 5,321
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Joe Kucinski
Seasoned HDF Member
Joined: Sep 2008
Posts: 14,165
Likes: 11,259
From: San Diego, CA
Yes...
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.....
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.)
Last edited by CSMHOG; Jun 25, 2019 at 02:11 PM.