I've seen the light
Club Member
Joined: Jun 2013
Posts: 6,386
Likes: 900
From: Columbus, Ohio
I've been working on my sense of adventure, but I just keep screwing it up!!
Seasoned HDF Member
Joined: Jan 2011
Posts: 157,462
Likes: 57,017
From: Michigan 15 Minutes East Of Hell
Yep ... ans astute observation on your behalf sir :>)
Seasoned HDF Member
Joined: Jan 2007
Posts: 20,616
Likes: 4,440
From: anacoco, la
is there enough room in the hd heads for 16 valves and the resulting actuating mechanisms? or is hd coming out with a 4cyl, 4 valve per engine next? 
Seasoned HDF Member
Joined: Sep 2008
Posts: 14,143
Likes: 11,212
From: San Diego, CA
For years, Harley didn't have ABS... also, in recent years, Harley was using DOT5 brake fluid....
Without ABS and with DOT5 fluid (non-hygroscopic) you could go years and years without noticing any bad affect from not changing the brake fluid...... It didn't mean the fluid wasn't breaking down or in need of replacing, you just didn't notice any catastrophic consequences.... probably the same with cars using either fluid, and without ABS....
Since DOT5 doesn't play well with ABS, all cars and motorcycles with ABS needed to switch back to DOT4 fluid (hygroscopic)... add the complexities of the valving involved with ABS, and the need to keep the fluid fresh became important....
I still think the HD ABS shouldn't fail in a way that makes the brakes inoperable, but design/engineering aside, the HD ABS issues have spotlighted this entire debate...
As with any safety requirement, most manufacturers will set a requirement that gives a good safety margin. That leads me to believe that 2 years is probably more frequent than actually necessary. But I don't have test data to show that 4 yrs (enter your best guess here) is OK, so I'll stick with the 2 yr recommendation...
When I learned of all this hygroscopic v non-hygroscopic fluids and ABS and changing fluid, etc, etc.... I got off my butt and changed the brake fluid in both my '03 Heritage (non-ABS w/DOT5) and my '12 Limited (ABS w/DOT4)...
I owned both since new and neither had ever been changed... 3.5 years on the '12 Limited and 12.5 years on the '03 Heritage...
The Limited fluid looked as bad as the Heritage fluid...
Based on all I've read and my own experience, I've now added the brake fluid change to my maintenance schedule ......
Without ABS and with DOT5 fluid (non-hygroscopic) you could go years and years without noticing any bad affect from not changing the brake fluid...... It didn't mean the fluid wasn't breaking down or in need of replacing, you just didn't notice any catastrophic consequences.... probably the same with cars using either fluid, and without ABS....
Since DOT5 doesn't play well with ABS, all cars and motorcycles with ABS needed to switch back to DOT4 fluid (hygroscopic)... add the complexities of the valving involved with ABS, and the need to keep the fluid fresh became important....
I still think the HD ABS shouldn't fail in a way that makes the brakes inoperable, but design/engineering aside, the HD ABS issues have spotlighted this entire debate...
As with any safety requirement, most manufacturers will set a requirement that gives a good safety margin. That leads me to believe that 2 years is probably more frequent than actually necessary. But I don't have test data to show that 4 yrs (enter your best guess here) is OK, so I'll stick with the 2 yr recommendation...
When I learned of all this hygroscopic v non-hygroscopic fluids and ABS and changing fluid, etc, etc.... I got off my butt and changed the brake fluid in both my '03 Heritage (non-ABS w/DOT5) and my '12 Limited (ABS w/DOT4)...
I owned both since new and neither had ever been changed... 3.5 years on the '12 Limited and 12.5 years on the '03 Heritage...
The Limited fluid looked as bad as the Heritage fluid...
Based on all I've read and my own experience, I've now added the brake fluid change to my maintenance schedule ......
Last edited by hattitude; Jun 28, 2017 at 10:30 AM.
Big Kahuna HDF Member
Joined: Feb 2010
Posts: 20,530
Likes: 2,305
From: texas panhandle
According to goggle, the jury is not in agreement. The only reason given to change brake fluid is to prevent the buildup of water in the brake fluid. May be a problem in some areas but I have never seen it.
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Seasoned HDF Member
Joined: Apr 2015
Posts: 10,058
Likes: 5,316
From using Google, like you, I found some automobile manufacturers do have brake flushes as part of their scheduled maintenance, but some do not, with Toyota and GM being at least two that do not.
Outstanding HDF Member
Joined: May 2015
Posts: 2,172
Likes: 377
From: Georgia
I don't understand why people are fighting this. It's inexpensive, literally $10 dollars or so, and easy to do so why not? Loss of braking performance happens so gradually you won't notice it but changing the fluid will likely show an improvement.
