Brake light stays on
Cruiser
Joined: Apr 2013
Posts: 201
Likes: 2
From: Colombia
Erik, try the WD-40 option.
Get a syringe, fill it with WD-40. Use a flash light and find a really small gap in the dust cover of the master cilinder. Press the brake so the cilinder is pushed in and leaves space for the wd-40 to enter. Move your face away and let go of the brake. Do a press release of the brake a couple of times so the oil moves all over the place. Repeat two or 3 times(it's a plus if youre able to flush the brake fluid as it will let you move the brake freely. then you can add fluid again.) Once everything is done and your brake fluid is at the required level, just ride the bike through city block (makes you use the brake more).
If doing this doesn't work, your brake cylinder was too corroded and wont fully come out and needs replacement.
If it works, in about a month or couple of weeks, inject some more. Ones is fine and no need to flush the system. Just make sure to press the brake while you fill with oil and remove your face once your about to release.
Hope it works.
Dont remember when i posted this solution but its been months since I've added wd-40 and its working great. Guess it was dust or corrosion.
Get a syringe, fill it with WD-40. Use a flash light and find a really small gap in the dust cover of the master cilinder. Press the brake so the cilinder is pushed in and leaves space for the wd-40 to enter. Move your face away and let go of the brake. Do a press release of the brake a couple of times so the oil moves all over the place. Repeat two or 3 times(it's a plus if youre able to flush the brake fluid as it will let you move the brake freely. then you can add fluid again.) Once everything is done and your brake fluid is at the required level, just ride the bike through city block (makes you use the brake more).
If doing this doesn't work, your brake cylinder was too corroded and wont fully come out and needs replacement.
If it works, in about a month or couple of weeks, inject some more. Ones is fine and no need to flush the system. Just make sure to press the brake while you fill with oil and remove your face once your about to release.
Hope it works.
Dont remember when i posted this solution but its been months since I've added wd-40 and its working great. Guess it was dust or corrosion.
Road Warrior
Joined: Jul 2012
Posts: 1,996
Likes: 417
From: Cranbourne, VIC Australia
I usually get about 3 years or so out of mine. I usually buy two or three master cylinder rebuild kits at a time, and rebuild it and clean the pistons in the caliper whenever it acts up (like right now as a matter of fact). Then I flush all the fluid when I bleed the brake, flush and bleed the rear for good measure, and go ride..... it takes me about 45 minutes or so, being careful and taking my time, and with fluid and parts, cost under $20 or so.
Seasoned HDF Member
Joined: Jan 2015
Posts: 15,995
Likes: 7,111
From: Sandy Eggo's North County
You realize the propellants in WD-40 can have a drying effect on rubber?
WD-40 is a "water displacement" product. Not really a very good lubricant. Maybe a "chain wax" product would be better suited? But, there again, it'll likely have n-propanol and that's very drying.
WD-40 is a "water displacement" product. Not really a very good lubricant. Maybe a "chain wax" product would be better suited? But, there again, it'll likely have n-propanol and that's very drying.
Extreme HDF Member
Joined: Jun 2014
Posts: 11,448
Likes: 2,299
From: NW Ohio
OEMs use silicone grease. It's available at most auto parts stores. I have at least three grades laying around. Shin Etsu is quite good for weather stripping...low friction and not terribly sticky (not AS bad with attracting dust). I think it has a teflon additive. Never tried it on a master cylinder, tho. I just found Shin Etsu this year. Til now I've been using a very high viscosity (and sticky) DuPont high vacuum grease. I use it on most anything rubber or plastic that needs lube.
At my last job we manufactured systems (that had to be Helium gas tight) with rubber seals and we used literal tons of various Dow Corning silicones. Both oils and greases.
At my last job we manufactured systems (that had to be Helium gas tight) with rubber seals and we used literal tons of various Dow Corning silicones. Both oils and greases.
Last edited by cggorman; Mar 14, 2018 at 03:23 PM.
Road Warrior
Joined: Dec 2017
Posts: 1,499
Likes: 2,831
From: Delaware
Had the same problem. Master cylinder rebuild will happen soon but in the mean time, I shot a TINY burst of WD40 in where the brake lever pushes in the plunger and work the brake lever in and out a bit. Its a short term fix, but I did it last fall and its still working.
Extreme HDF Member
Joined: Jun 2014
Posts: 11,448
Likes: 2,299
From: NW Ohio
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