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Low Front Brake Fluid

20K views 31 replies 14 participants last post by  dehingst 
#1 ·
My front brake fluid is getting very low so I think I need to do something about that soon. :p I think it's just low from pad wear... Any idea how many top-ups it takes before the pads need replacing (0?). I'll do my best to check the pads for wear, but I'm honestly much better at a computer keyboard than with a wrench in my hand. :)

According to my service manual you can pretty much just open the reservoir and top it up. If you end up with air in the lines (the lever feels spongy) then you need to go through the whole hassle of bleeding the brakes... IIRC, the owner's manual recommends against just topping up the fluid, and recommends taking it to a dealer for service. Is that just for legal reasons to deter people like me from ending up with air in the lines and killing themselves? :)

I could take it to my dealer, but I don't really trust them, and I don't want to pay more than needed if it's a simple job. I also am using the bike more or less rain or shine right now and don't want to risk losing it for a day or two. My cage rim is bent and doesn't hold air long and it's a pain in the ass to haul my big air compressor to a power outlet... :grin

Anybody done this job yet?
 
#2 · (Edited)
If you replace pads or have them replaced the level will be near back to what it was once pistons pushed back in.

Check pads for wear look in back of caliper as it says so in owners manual, usually level doesn't drop that much due to pad wear check for any leaks to.
 
#3 ·
Thanks. I'll have to check the service manual again, but I think for pad replacement they include bleeding the line... If it can be done without affecting the fluid then perhaps that is a good option, but only if the pads are actually worn... I'll have to see.
 
#4 ·
I think this is something you can easily do as long as you take your time and not rush it. Ideally your brake line is a sealed system, so changing pads shouldn't affect this. However, sometimes dirt and grime can get into the system by sneaking past the rubber piston boot.

Is your fluid still a nice tea color or is it brown?

As lee1980 mentioned, the level may return when you replace the pads. Therefore you will want to replace the pads and then top off if necessary. Just be careful not to overflow an open reservoir as brake fluid does wonders with removing paint from metal surfaces.
 
#7 ·
You won't get air in the line if you merely open the reservoir. You'd have to let the fluid level drop down to near the bottom of the reservoir for that to occur.
Having said that, under normal circumstances, you should not have to top the fluid off. There should be sufficient fluid in the system such that the fluid does not get to the minimum level until the pads are worn enough to be replaced. When you replace the pads, you should just push the pistons back to accommodate the new pads, and the fluid level in the reservoir should go back up.
If, however, the dealer didn't fully top off the reservoir during setup, you might be low. In that case, if you're low but the pads are still rather good, adding just enough fluid to keep you a little above the minimum will be fine. Just don't add more than necessary; when you do eventually replace the pads, you'll run the risk of sending a boatload of fluid out the top of the reservoir when you push the pistons back.
As always, any time you open that reservoir, drape a thick towel or two over anything that brake fluid might drip onto; that stuff is great paint stripper.
Because it's probably been about a year, it's not a bad idea to replace the fluid now anyway, in order to keep performance up and prevent any absorbed water in the fluid from causing damage, though I usually let it go for 2 or 3.
 
#9 ·
my brake fluid went low few thousand miles back, so i bought an small bottle of brake fluid, opened the reservoir and carefully filled it up. it is only now that i am changing my pads (18k), and btw, the fluid has stayed the same since the refill... brakes have been working fine so nothing wrong with them...
 
#13 ·
my brake fluid went low few thousand miles back, so i bought an small bottle of brake fluid, opened the reservoir and carefully filled it up. ...
Exactly the same with me.. only 35% worn pads at the time too.. Still going strong and level has maintained. No leakage either.

Of course when it comes to changing the pads some fluid will ultimately need removing which I will make sure the 'technician' knows about - don't want it overflowing etc.

Think it maybe a 'normal' thing to happen.. so don't stress over it. Top up and enjoy.

(make sure you cover the base of the reservoir and surrounding area with some rags so you don't accidental drop any fluid anywhere. Very corrosive stuff.)
 
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#10 ·
I once looked into the window and saw no fluid at all, I was all set to call a tow-truck, then I straightened the bars and it came back to normal. That was how I learned to check fluid levels with the bike level and the bars straight. :)

I check it at least weekly now.
 
#11 ·
Thanks, guys. Useful advice that I'll attempt to put into practice very shortly. Lots of stuff that wouldn't have occurred to me and that the service manual doesn't document well.

The service manual has you checking for a "wear limit groove" on the pads. I'm not exactly sure what I'm looking for. I assume nothing has to come off of the bike to inspect them because the service manual doesn't seem to mention anything (unless it is in a previous chapter) so I guess you must be looking from the back because the forks block the front...

My dad is really good at this stuff, but unfortunately he's also really uncomfortable with me having a motorcycle. :(
 
#15 ·
Here's a picture. The brake pads are from my 230L, the smaller pads are the rear pads. You can barely see the trace of the groove in one of those rear brake pads. I use the rear brake a lot in the dirt. :grin

Best of luck.

 
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#17 ·
Thanks, @jsonder, that should help a lot! So you don't want to be looking at them lengthwise, but depth-wise? :confused2

Stopped at the dealership yesterday on the way to work to buy brake fluid... They have separate service counters for cars and small engines... I say I need brake fluid for my bike. He asks me what kind that is. I didn't bother checking so I went off memory. I said I think it's DOT 4. He says they don't have that, and says he'll just grab what they use... :eek: He comes back with DOT 3... Says that is what they would use. Says they only stock DOT 3 and DOT 5. I say OK, you're sure it's compatible with my bike? He says he'll check the computer to be sure. Comes back DOT 4. Other guy goes into the back and returns with DOT 4. First guy asks where he found it. Second guy says it is between the DOT 3 and DOT 5...

 
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#19 ·
bambams: Did you apologize for disturbing their day? It _is_ the Canadian way. :smilecolour
 
#20 ·


Anyway, I looked for the wear indicator grooves today and to me it looks like there is still plenty of pad left... But if I top up the fluid I might have to drain the fluid in the future to expand for bigger pads... It is a dilemma. Replace pads early or exacerbate job later. :(
 
#22 ·
Seems like a common occurrence,anyone add a reservoir similar to a super sport ex. Yamaha R6? Or is that too much money/work hahaha
 
#23 · (Edited)
Topped up the fluid today. Everything seems OK! There is a bit of a story though... OK, so I opened my toolkit, pulled out the screw driver and handle, and used it to remove the 3 piece assembly (plus 2 screws) involved. Simple as can be. I set it all down by my helmet 10 feet away so I wouldn't kick dirt on it. I struggled to get the goddamn seal off of the brake fluid bottle before just resorting to stabbing it with the driver...

I carefully covered the bike surrounding the reservoir with rags to hopefully catch any spills. Then I sat on the bike to level it while I poured the fluid in. And I really didn't think this all the way through.. I carefully poured the fluid, worried I would spill from a full bottle. A drop ran down the bottle, but I managed to stop and catch it with a rag. That was all it needed anyway. The level was **** near perfect. Awesome, just had to install the assembly again... Which is 10 feet away. I'll just set the bike back dowwwooooh ****. If I set the bike back down on the kickstand the brake fluid will leak out of the reservoir... D'oh!

My neighbor was sitting over in his truck 80 feet away. I thought about trying to yell at him, but I wasn't sure I'd be able to get his attention, and I barely know him anyway so I didn't want to bother him.. I looked around my parking lot for nearer people. My next door neighbor was dumping some trash in the dumpster, but I didn't want to bother a proper lady to come and handle bike parts lined with brake fluid...

Instead, I caaaaarefully reached down and set the bottle of brake fluid on the ground. Then I stood up with the bike grasped by my tender loins and reached into my extremely tight jeans pocket to pull out my large smart phone... Then I carefully sat back down and texted for my brother, who lives in the same apartment building, to come and help me in the parking lot. I waited a short while. It felt like an eternity with no response so I followed up with another text, "ASAP..." I waited a few minutes longer and decided to try calling him instead.

He answered right away. I explained the situation and he came down and handed me the pieces. I carefully installed them. The service manual has a torque spec., but it's like 1.5 lb/ft or something. I just went with carefully tightening the screws without stripping them and that had to be good enough.

Once I had everything back installed and tight I carefully squeezed the brake lever to see how it felt. I did this 10 times or so and everything seemed good so I took it for a ride! All seemed good. For good measure heading down the main business strip of town, with no traffic behind me, I went for an emergency stop from about 70 km/h and locked the rear up good. :) Well, I had meant to test the front, but that seemed to be working good too. :thumbsup

Thanks guys. Here are a few not very useful pics...

I did my best to get my phone in where it could photograph the wear indicator groves (as far as I can tell). The angle really sucks so I have no idea if this is even looking at the pads, but I see groves in the picture so that's something! I am able to actually see the pads though from a different angle so I'm fairly certain that they're good...



Let me know if I'm looking at the right thing...

Here are a couple of shots of the brake fluid while "low". Notice that when the bike is tipped over on the kick-stand the fluid is already pretty close to spilling out...




Here are a couple of shots after I topped the fluid up. I guess you wouldn't want to remove those caps with the bike on the kickstand if the fluid is "high"...


 
#24 ·
Congrats on a job well done. And yes, your pads still have a lot of wear left.

:beers
 
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#26 ·
How old is your bike and how many km did you ride it? A low level on a relatively new bike indicates a leak somewhere. Did the brakes feel spongy?
The CBR250 manual says to change fluid after two years; it should be good for at least three. I've had bikes several years old with the second set of brake pads almost gone and the fluid was still the right amount and had a good color.
If you think the level may be low, take a flat wide object like a butter knife and carefully slide it between the pad and the disc, try not to damage the pads. Then angle the knife and push the pad in, away form the disc, just a little bit. That way you push in the piston in and put pressure on the system. The fluid level should be back to normal. If it is still low, it's time to change it.
I wouldn't top it off; you can't use brake fluid later, it takes the humidity out of the air and is then dangerous to use because it compresses. If you open a bottle you have to use it; if you use only 10% you have to dump the rest. That's why it says "Only use a sealed bottle". Since you're opening the system you may as well bleed it entirely and use the whole bottle.
DOT3 and DOT4 are compatible, but DOT5 is a different animal.
A mechanic once told me about a guy who thought DOT 5 is better than DOT 4 and filled it into his brand new bike which brakes were designed for DOT 4. Not long and the fluid started to leak because it ate up some gaskets; he had the stuff all over and almost got into an accident because the brakes didn't work properly.
Know what you're doing before you eff with it! :)
 
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#29 ·
Nice work :)

Even with the bike on the side stand, if you rotate the bars you can get the brake reservoir to be pretty level. Give that a try next time.

Mine was the same: nothing really to do with pad wear: the reservoir isn't level when the bars are straight of the R, it's mounted on an angle on the clip-ons. On the F and X, being mounted on the proper bars, its level. It's basically just a cost saving measure - one part for all 3 models ;-)

If you rotate the R bars, you can get it pretty level ;-)

That and mine wasnt filled "full" from new like yours.

Dave
 
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#30 ·
Nice work :)
Thanks! :)

Even with the bike on the side stand, if you rotate the bars you can get the brake reservoir to be pretty level. Give that a try next time.
The thought never even occurred to me. :bowdown I'll try to keep it in mind next time. :thumbsup
 
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#31 ·
Last Thursday I visited a guy from my motorcycle club to flush my brake fluid. I knew it looked discolored and the guys in the club say to change it every 2 years. This guy is a retired millwright and has years of experience maintaining bikes. He made short work of flushing the brake fluid. We had a tool that we borrowed from another guy in the club to suck the old fluid out. It probably only took him about 15 minutes and we were done. The fluid looked worse than I thought so I'd definitely recommend anybody that has had the bike for 2 years to have it changed.
 
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