Changing Brake Fluid???
Stellar HDF Member
Joined: May 2006
Posts: 2,809
Likes: 4,146
From: NC
I've always assumed bad brake fluid would be a gradual problem, not a catastrophic failure. I've replaced fluid during rebuilds and parts replacements but never just to refresh fluid. 45 years, probably 12 or so bikes/cars/trucks, never an issue.
Road Warrior
Joined: Jul 2014
Posts: 1,584
Likes: 520
From: VA
Harley has had known issues with their ABS system if the fluid isn't changed. Not sure what year models are affected. I change mine every 24 months per the schedule. You can get some but not all of the fluid out if you do it yourself on ABS bikes.
Seasoned HDF Member
Joined: May 2018
Posts: 5,814
Likes: 7,146
From: Las Vegas
I've always had the same thoughts as you. But it's more critical now than back in the day. Moisture in the fluid causes corrosion in the ABS pump which leads to failure, and the same corrosion in the master cylinder and calipers leads to lower efficiency. It's worse in high humidity locations, but it's real everywhere. My SGS is 3 years old and the moisture content is under the 3% recommendation so I haven't done the flush yet, but I should - it's pretty dirty.
Outstanding HDF Member
Joined: Mar 2018
Posts: 2,773
Likes: 2,261
From: Ft. Wayne IN
Get it done. Cheap insurance. Glycol-based brake fluids are hydrofilic (attracts water). DOT 4 is glycol based and it's in your 2018 Heritage system. You should also cycle the ABS system when flushing, per HD. I did mine at 2 years; cost about $180. An Indy shop near me now has the capability to cycle the ABS system (I'm told) and is less expensive. Mine is due again in about 6 months and I plan on getting it done again.
Road Warrior
Joined: Sep 2016
Posts: 1,952
Likes: 903
From: South Florida (Ft Myers area)
I would just test it, good brake fluid is good brake fluid. Remove good brake fluid and replace it with good brake fluid makes absolutely no sense.
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Tourer
Joined: Feb 2012
Posts: 321
Likes: 85
From: Maine
Same here........Never did a total flush.....and no issues. 40 years and many bikes. I think it is over thought. Just another way for HD to get money out of people that don't know better. "If it ain't broke, don't fix it."
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Seasoned HDF Member
Joined: Feb 2008
Posts: 22,999
Likes: 11,439
To answer OP question if you have ABS 2 years. If not test and replace as needed.
Yes you can do it your self many products on the market to cycle ABS.
Cruiser
Joined: Apr 2021
Posts: 186
Likes: 103
From: Austin, TX
In my experience, the biggest contributing factor to needing to change brake fluid is the heat I've built up (or haven't) through the type of riding I'm doing. On my Harleys, I've gone 3,4,5 years plus w/o needing to change. On my track bikes, the need to change brake fluid is on a scale of hours spent on the track. Different brake fluids have different boiling points - once it hits that or comes close to it consistently, it really needs to be changed. If I'm never getting close to its boiling point, brake fluid can last a really long time if the system remains sealed.
After a lot of experience, I now only use Motul RBF 660 in all my bikes when I need to do a change.
After a lot of experience, I now only use Motul RBF 660 in all my bikes when I need to do a change.