I was installing my new rearset (brake line question)

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Henry
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Joined: Sat Nov 19, 2011 12:09 am

I was installing my new rearset (brake line question)

Postby Henry » Fri Jan 20, 2012 11:29 pm

So when i was putting in my new race rearsets my brake line was rubbing up against the lower part of my rear suspension, So i had loosen it to rotate that hard "L" shaped piece a bit to the side.
Due to loosing it the brake fluid leaked a bit, (very slight, enough that i could clean up with my fingers) So do i need to drain and put new brake fluid in?

I read off of riderforums that someone said if that happens "air could have gotten in and its not worth the risk"?

Thanks, sorry if this is a stupid question, never messed with the break line before.
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Retro Rocketeer
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Location: Boise, ID

Re: I was installing my new rearset (brake line question)

Postby Retro Rocketeer » Sat Jan 21, 2012 12:35 pm

If that's all that leaked out, I'm 98.87% sure you'll be just fine (gotta leave myself some percentage of a liability out). The amount of air that could have gotten in wouldn't be enough for a catastrophe. If any air got in, you might notice a minor amount of extra travel, or a little mush in the pedal. That small of a breach, you likely notice nothing, as nothing likely happened. This is easy to test for. Go out and ride. Does your rear brake feel any different? Is it different enough for you to care, or does it still stop you?

Believe it or not, it could have an upside. What? An upside to having air in the line? Some racers purposely allow small amounts of air into the rear brake to help prevent lock up. Under heavy braking, do you often lock up the rear wheel? (You do practice often, right?)

That small compromise to the atmosphere isn't going to suddenly turn your fluid worthless. Your fluid turns worthless on its own anyway. Depending on use and desired feel, the fluid should be swapped out periodically anyway. Air and water contaminates the system on its own, no matter how tight you think the system is. I swap the fluid in my street and dirtbikes every spring. I "freshen" the front brake fluid of my race bike after every weekend by sucking out the amount equal to what my resevoir holds. It all depends on how much feel you desire. Heat destroys the fluid faster than a little water and air built up over regular use.

To summarize, if it were me, I'd make sure the banjo bolt is snug, work the pedal for the amount of resistance I'm used to, ride it if in doubt, and likely leave it.
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biketechted
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Re: I was installing my new rearset (brake line question)

Postby biketechted » Sat Jan 21, 2012 9:10 pm

You should do yourself a favor and go buy a cheap $40 mityvac brake bleeder from your local auto parts store and eliminate the 1.13% chance that something will go wrong.
I had a small amount of air left in my rear brake line (specifically in the caliper) after I installed a new one. When I applied my brake, it would cause the pads to not retract fully, drag on the rotor, and overheat the fluid causing it to expand and eventually lock up the rear brake.
When I bled it again, there were no more than 4 bubbles worth of air left that was causing my problem.
Currently I have no problems and that was over a year ago.
Henry
Posts: 29
Joined: Sat Nov 19, 2011 12:09 am

Re: I was installing my new rearset (brake line question)

Postby Henry » Sun Jan 22, 2012 4:13 am

Well to be honest I haven't rode it yet since I'm still working on it. Trying to make this project bike into a track/commuter bike, then eventually get a track only bike, anyways I should be done working on it this week depending on work. Yeah I am going to try to ride it with caution for few days before I take it to the track I guess.

biketechted, how can you tell if there how many bubbles u had? I would like to see if I even have any bubbles or if i have way too many lol.

Retro Rocketeer, Iv been to the track just a handful of times, I want to start going regularly soon. But I use my bike to commute at the moment. I recently started getting a feel for my bike, I like to have fun ride a wheelie every now and then. Anyways what you posted gave me a lot of insight on this and I appreciate it.
I am going to try to ride and see if I feel a difference or if something does happen, however I think I need to invest in a brake bleeder lol.
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Retro Rocketeer
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Location: Boise, ID

Re: I was installing my new rearset (brake line question)

Postby Retro Rocketeer » Sun Jan 22, 2012 10:52 pm

Without question, a vacumm pump brake bleeder is handy. I use the beejeezus out of mine. The rear brake is a cinch to bleed with the trusty hose and bottle pump method, as its all on the same side and you can pump the pedal and turn your wrench on the bleed nipple all yourself. Done that at more than a few motocross tracks and desert rides.

Something else you can do if you have any suspicion of air at the master cylinder. Air always rises to the highest point it can reach. Unbolt the rearset you just installed. Raise it to allow air to travel up the brake line through the master cylinder and into the reservoir hose. Tap the brake line to encourage bubbles to travel, and pump the pedal some as well.
Henry
Posts: 29
Joined: Sat Nov 19, 2011 12:09 am

Re: I was installing my new rearset (brake line question)

Postby Henry » Sun Jan 22, 2012 11:52 pm

Retro Rocketeer wrote:Without question, a vacumm pump brake bleeder is handy. I use the beejeezus out of mine. The rear brake is a cinch to bleed with the trusty hose and bottle pump method, as its all on the same side and you can pump the pedal and turn your wrench on the bleed nipple all yourself. Done that at more than a few motocross tracks and desert rides.

Something else you can do if you have any suspicion of air at the master cylinder. Air always rises to the highest point it can reach. Unbolt the rearset you just installed. Raise it to allow air to travel up the brake line through the master cylinder and into the reservoir hose. Tap the brake line to encourage bubbles to travel, and pump the pedal some as well.


Hm I like that idea, seems to be on the safe side. I will do this first thing in the morning.

I start paining the body tomorrow! I got a metallic black and that new Camaro green, trying to think of how I should paint it. Its the full catalyst with a 636 headlight conversion.

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