Important!

[oldschoolorange]

I know better than this but obviously was not paying attention. Keep an eye on how much fluid you put in your master cylinder. I was beating the hell out of my bike today and had bled the brakes the night before and put too much fluid in. needless to say the thing locked a front tire on some gravel and went down . I am ok and the bike is decent but now I have to fix a dented tank and a busted signal light.

[chef1366]

Too much brake fluid should not lock your brakes.

[denydog]

Glad you are OK, but I have to agree that excess brake fluid in the MC reservoir should not affect how your brakes operate. Maybe if the fluid got hot enough to expand and had no air at the top of the reservoir to allow room for expansion, and caused the whole system to pressurize and lock up the brakes. Sounds pretty unlikely though.

It doesn't take very much to lock the wheel in gravel under most any circumstance, speaking from experience.

More likely to have a big mess from overfilling the master cylinder, also speaking from experience.

[SqDancerLynn1]

It could if their was NO room for the master to breath a little

[Dave8338]

It could if their was NO room for the master to breath a little

That would take some "EXTREME" riding, on the brakes 24-7 and allowing for no cooling effect from the calipers, lines, or master reservoir. May be possible in a "perfect" situation, but highly unlikely...though if the pads were dragging and continuously building heat, I suppose anything's possible. :?

[chuckycheese]

As Denydog implies, maybe you accidentally locked it up. Whenever you've got disk brakes, sand, gravel, oil and, especially, grass can be a real problem. Long ago, I locked up the front wheel on a Sportster while riding on grass.....I could hardly believe how easy it was to do.8-[

[oldschoolorange]

The problem was that there was no room for the fluid to expand, there may have been some slight drag on the caliper by the shoes but I am not sure. once you overfill it and things started to heat up it just starts a huge cycle of heating up and expanding.

I had felt the front suspension compressing the turn before and was wondering what was going on as I was not on the brake. Once I straightened out the forks were still compressing even when I was on the gas. At this point I knew something was wrong with my brake. I did not touch the front brake
to stop I was going in a straight line coming to a stop when the front end locked up and washed out from under me at about 5kph. If there was no sand on the road then maby I could have held it upright but I am not going to repeat what I did just to see.

There was no room for expansion, like a dumbass i filled it right up to the top and wiped off the excess that came out when I put the cap on.

I needed some cheering up so I went out and bought myself a nice new welder today, damn I love credit cards

[earlfor]

Every motorcycle brake master cylinder I have has a fill level line on its side. :-)

E.

[Steve]

I think it is more likely that the little bleed hole is plugged, and the pressure that builds up in the caliper could not vent into the master cylinder reservoir. I took my son's bike around the block last summer (about 5 miles) and had to bleed the front brake so I could make it home. Cleaned out the bleed hole and have not had a problem with it since.


.

[oldschoolorange]

Yeah I should have a look at the master anyways. Oh an Earl, thanks for the tip you smart ass

[BentRod]

ya know what the terrible part of this is? When i went down on that bike last month (at about 3kph), I busted up my knee to save the tank and engine, on the same side that is now banged up...

for those of you interested.. I went down because the steering locks were too large, and I couldn't turn tight enough.. oh well..

[twistedwankel]

I know better than this but obviously was not paying attention. Keep an eye on how much fluid you put in your master cylinder. I am ok and the bike is decent but now I have to fix a dented tank and a busted signal light.

Those of us who do hurried things appreciate your information to avoid making a similar mistake.

I have found that by waiting until my bike project is completed before rewarding myself with 3 beers has greatly improved the quality of my repairs.8-[

[oldschoolorange]

lol I hear you on that one, Once you get into the booze you take a look at what you were working on the next day and you can tell where it started to hit you

[rphillips]

Remember the rubber boot thing, that goes in above the fluid & under the cap, it creates an air space that keeps expansion of fluid from locking the wheel.