Front brake loses pressure, comes back after a few minutes
Supporter
Joined: Jan 2022
Posts: 565
Likes: 471
From: Sapulpa, OKlahoma
Sounds like air &/or moisture in the brake fluid or a seal in the master cylinder leaking by.
Since the brake action returns to normal after a while I'd lean more toward air &/or moisture in the brake fluid. Moisture will boil under the right conditions and cause it to lose pressure. Might be time for a brake fluid flush.
I'm stumped as to why it happens in relation to the engine issue, unless the engine is overheating and causing the moisture in the brake fluid to boil.
Since the brake action returns to normal after a while I'd lean more toward air &/or moisture in the brake fluid. Moisture will boil under the right conditions and cause it to lose pressure. Might be time for a brake fluid flush.
I'm stumped as to why it happens in relation to the engine issue, unless the engine is overheating and causing the moisture in the brake fluid to boil.
Stellar HDF Member
Joined: Mar 2020
Posts: 2,235
Likes: 2,155
From: West Coast
Did you **** off the Mrs.'s? look for cut lines. It does sound like dragging pucks and boiled fluid like posted above. Engine issue could be overheating from trying to override the brake.
Seasoned HDF Member
Joined: Mar 2010
Posts: 38,416
Likes: 6,366
From: Honah Lee
Hold a firm braking amount of pressure on you lever and do the pedal also. Hold it a timed minute. They should not drop.
If they do, vacuum bleed both masters. Do not pump it with the lever or pedal. Recheck the pressure test. If it drops, rebuild both the master and
It also available on the Harley parts on line.
PS...Welcome to the HDFORUM. Only as a suggestion, make another new thread over in the newmember welcome area to say hello...
https://www.hdforums.com/forum/welcome-area-only-4/
If they do, vacuum bleed both masters. Do not pump it with the lever or pedal. Recheck the pressure test. If it drops, rebuild both the master and
It also available on the Harley parts on line.
PS...Welcome to the HDFORUM. Only as a suggestion, make another new thread over in the newmember welcome area to say hello...
https://www.hdforums.com/forum/welcome-area-only-4/
Last edited by Jackie Paper; Jun 3, 2024 at 08:15 PM. Reason: Error in type of fluid
HDF Community Team
Joined: Jan 2022
Posts: 1,117
Likes: 856
From: B.C.
Hold a firm braking amount of pressure on you lever and do the pedal also. Hold it a timed minute. They should not drop.
If they do, vacuum bleed both masters. Do not pump it with the lever or pedal. Recheck the pressure test. If it drops, rebuild both the master and caliper.
Pretty sure, your system is DOT 5. Be sure to use the special piston grease for internal lubrication . Instructions come with the Harley kits.
It also available on the Harley parts on line.
PS...Welcome to the HDFORUM. Only as a suggestion, make another new thread over in the newmember welcome area to say hello...
https://www.hdforums.com/forum/welcome-area-only-4/
If they do, vacuum bleed both masters. Do not pump it with the lever or pedal. Recheck the pressure test. If it drops, rebuild both the master and caliper.
Pretty sure, your system is DOT 5. Be sure to use the special piston grease for internal lubrication . Instructions come with the Harley kits.
It also available on the Harley parts on line.
PS...Welcome to the HDFORUM. Only as a suggestion, make another new thread over in the newmember welcome area to say hello...
https://www.hdforums.com/forum/welcome-area-only-4/
Unless someone converted it, it is dot 4. For 2008.
Last edited by Highway Handler; Jun 3, 2024 at 07:29 PM.
Road Captain
Joined: Sep 2012
Posts: 647
Likes: 151
From: Tampa, FL
If you have hand guards over the levers check to make sure the brake side hasn’t accidentally been pushed into the lever. I met a rider last week who t9ld me about chasing a brake problem, including fluid and hardware changes only to learn later that his hand guard was lightly engaging the front brake.
Road Warrior
Joined: Dec 2019
Posts: 1,783
Likes: 938
From: Ohio
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Southpaw Super Glide: A Left-Hand-Drive 1979 Harley FXE Built to Fit the Rider
Verdad Gallardo
Grand HDF Member
Joined: Jan 2012
Posts: 4,453
Likes: 2,839
From: Oklahoma
Have you ever cleaned the brake pistons in the front calipers? Accumulated brake dust and road contamination can make the pistons jam in their bores and keep the brake pads firmly against the disc after you have released the lever. That is a common cause of the heat generation and temporary loss of brakes described above. Has your fuel economy noticeably gone down also? Dragging brakes commonly cause that also.
Thread
Thread Starter
Forum
Replies
Last Post
DK Custom
Tri Glide, RG3 & Freewheeler Models
45
Jun 24, 2024 06:17 PM