Brake failure
Outstanding HDF Member
Joined: Sep 2005
Posts: 2,600
Likes: 7
From: Minnesota
While riding the Needles during my recent trip to Sturgis I had a major failure with my rear brakes. After making the 5 mph switchback, right hand turn uphill, I was preparing for the next curve. A 20 mph left curve In the decent from the peak of the previous 5 mph switchback. I applied my rear brake to reduce speed to enter the turn. The peddle went all the way down with no response from the brake. After a butt load of down shifting and a small amount of front brake I maneuvered the curve. I rode about another 2 miles of decent in first gear while riding the front brake. I caught up with my group at the end of the single lane tunnel where there was an area to pull off the road. My buddy said my brakes may have glazed over, I disagreed as that would not have changed the range of brake peddle. That also eliminated no brake pads. I removed the cover of the Reservoir and the level was full. I replaced the cover and pumped the brake peddle and my brakes returned. I can only assume that I had an air bubble in the system. The elevation is over 5,000 feet coming from my Texas home at basically sea level. I am thinking that maybe the change in altitude could have made the bubble larger, like the bends when diving. Has anyone ever experienced or heard of anything similar? I contacted my local dealer and they have never heard of what happened. I am going to use a vacuum pump and replace the brake fluid. Looking for the cause as the pucker factor was an 11 on the scale of 1-10.
BTW, my pucker factor on Needles hovered somewhere around yours when I was pulling a trailer and saw a sign saying 'use caution' that they had just resurfaced the road with oil and granite chips. The friggin sign was posted after it was too late to try to turn around. I could feel the trailer pushing the rear wheel at every turn. My hands were cramped from squeezing the grips and I was glad that it was over.
Road Warrior
Joined: Oct 2006
Posts: 1,350
Likes: 46
Flush your brake fluid, Dot 5 can absorb moisture fairly quick. That & the thin air & use of the brake more than normal, it probably did boil the brake fluid in the rear caliper. In the race cars that we work on we have to flush the brakes every year, just because of that reason. If the hose went bad the brakes would not have come back & you would have lost brake fluid. Glad you can ride & got through it safely.
Toby
Toby
Thread Starter
|
Road Warrior
Joined: Mar 2009
Posts: 1,518
Likes: 59
From: Port Neches Texas
If you were a bit heavy footed on the brakes prior to the failure I am betting that the fluid got over heated and caused the pedal to go down. I have done just that before and once the fluid cooled down all was good again. However I would change that fluid the 1st chance you get.
Stellar HDF Member
Joined: Jan 2008
Posts: 3,036
Likes: 65
From: Earth
Changing fluid on a bike without ABS is fairly straight forward. If you keep the master filled and only push fluid while full you will not be pushing any air. I have bled may systems without issue. Now ABS bikes, that I haven't done yet.
Thread Starter
|
Road Warrior
Joined: Mar 2009
Posts: 1,518
Likes: 59
From: Port Neches Texas
If your rotors had glazed it would be obvious. They'd be shiny as a mirror. I never heard of a air bubble due to the change in altitude but I'd think it is plausible and pulling some fresh fluid would be good in any event.
BTW, my pucker factor on Needles hovered somewhere around yours when I was pulling a trailer and saw a sign saying 'use caution' that they had just resurfaced the road with oil and granite chips. The friggin sign was posted after it was too late to try to turn around. I could feel the trailer pushing the rear wheel at every turn. My hands were cramped from squeezing the grips and I was glad that it was over.
BTW, my pucker factor on Needles hovered somewhere around yours when I was pulling a trailer and saw a sign saying 'use caution' that they had just resurfaced the road with oil and granite chips. The friggin sign was posted after it was too late to try to turn around. I could feel the trailer pushing the rear wheel at every turn. My hands were cramped from squeezing the grips and I was glad that it was over.
Road Master
Joined: Jun 2006
Posts: 812
Likes: 0
From: Jaw-Jaw (Near The BIG Chicken!)
Brake fluid is hygroscopic (absorbs water), however I'd be surprised it a 2010 scoot would have enough moisture in it so soon as to boil... What color was the brake fluid when you checked it? I'd be looking somewhere else in the system for the fault, but like others have said, wouldn't hurt to replace the fluid and see if you can duplicate the problem, less the pucker factor, of course.
Thread Starter
|
Road Warrior
Joined: Mar 2009
Posts: 1,518
Likes: 59
From: Port Neches Texas
Cherokee, when you changed the fluids is there any indication that the fluid boiled, color, odor, etc.
Spider Pig, I have never changed brake fluid on bike, manta times on my vehicles. I was going to use my small hand held vacuum pump to eliminate any air entering thru the Petcock valve, maybe overkill but I sure don't want to experience that again
Spider Pig, I have never changed brake fluid on bike, manta times on my vehicles. I was going to use my small hand held vacuum pump to eliminate any air entering thru the Petcock valve, maybe overkill but I sure don't want to experience that again
Stellar HDF Member
Joined: Jan 2008
Posts: 3,036
Likes: 65
From: Earth
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
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
The Best and Worst Harley-Davidson Moves of 2025
Verdad Gallardo
Stellar HDF Member
Joined: Dec 2005
Posts: 3,302
Likes: 274
From: Milton, Delaware
I tend to agree with the others who suspect over heated/boiling brake fluid.
I use the following method to flush brake fluid.
Go to a surgical/medical supply store and pickup a large syringe ($5) and a length of surgical tube that will fit over the (small) end of the syringe.
Clamp/safety wire/tie wrap the other end of the tubing over the bleeder valve. (this is to keep it from popping off when pressure is applied)
Fill the syringe with fresh brake fluid.
Remove the master cylinder cover.
Remove most of the brake fluid (turkey baster works well).
SLOWLY AND GENTLY compress the syringe, forcing the brake fluid thru the bleeder and back to the master cylinder.
Be careful that you don't overflow the master cylinder! (use the turkey baster)
Also, don't let the syringe become empty to the point of introducing air thru the bleeder nipple.
TADAH! You've just replaced all your brake fluid AND bled the brakes.
This works great for finicky front brake bleeding, so I use it on both.
I use the following method to flush brake fluid.
Go to a surgical/medical supply store and pickup a large syringe ($5) and a length of surgical tube that will fit over the (small) end of the syringe.
Clamp/safety wire/tie wrap the other end of the tubing over the bleeder valve. (this is to keep it from popping off when pressure is applied)
Fill the syringe with fresh brake fluid.
Remove the master cylinder cover.
Remove most of the brake fluid (turkey baster works well).
SLOWLY AND GENTLY compress the syringe, forcing the brake fluid thru the bleeder and back to the master cylinder.
Be careful that you don't overflow the master cylinder! (use the turkey baster)
Also, don't let the syringe become empty to the point of introducing air thru the bleeder nipple.
TADAH! You've just replaced all your brake fluid AND bled the brakes.
This works great for finicky front brake bleeding, so I use it on both.