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Discussion Starter · #1 ·
I dunno if I should really be worried about this, everyone I ask says that there's a problem but they don't know where it's coming from or how it's happening, and frankly, I'm a bit stumped as well. Only about 1-2k miles after rebuilding the front caliper and master cylinder and putting in new pads I noticed decreased braking power. Seems as if I have to pump my brake to make it work the best that it can. It's the worst in the morning when I'm going to take it for its first ride in the day. When I was on my latest trip I could tell that the master cylinder was leaking. It looked like it was around the banjo bolt, but I was told that if it was leaking there, the bolt would always be wet....though it seemed like it'd only leak after continously going long miles. My guru-uncle thinks it's leaking from the top of the master cylinder. I saw fluid appear there, around the banjo bolt, some sprayed onto my gauges, and once some pooled up on the brake hose (it kind of curves down a bit). I only saw it leaking when I went on my trip, now riding around town the only evidence of it is feeling moisture when running my finger along the cap. The quality of my front brake gets even worse when it rains, I either have to pump it more, or the pumping won't even make it better.





I'm stumped on it...I rebuilt EVERYTHING in the front brake system, though we are using the old brake hose...though I doubt that that would cause this kind of problem.



The only related issues are in the front end. I have a new one, I just haven't had time to put in the fork seals or anything yet. Seems like the current forks may be bent, the pistons inside of the forks are gunked up, and I just have a very stiff ride. I don't think that this would really create that kind of problem though. My mechanic says that he thinks that it's dragging, upon watching me struggle to push it into his garage (I stopped by to buy some plug caps, and it was raining, and he let me push it into his garage to keep it dry). It doesn't make any noise like when it has dragged in the past though. Maybe I shouldn't worry about it until switching the forks/front end? Or could it be something else entirely?
 

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If you have anything "wet' around the lines, master cylinder, etc, then you have a leak even if only slightly. This could allow air/or moisture to get into the system (and probably has based on the issues).



First thing, find the leak and correct it even if it requires a rebuild. Second, replace your hose. You can get a nice braided hose for about $50. A complete rebuild and a hose is about $100 (cheap when you need to stop!). Flush the system with new clean fluid of the appropriate type and bleed the system thoroughly. After bleeding, pull the lever back with zip ties or another method to keep pressure in the system, and let it set overnight. This will firm up the "feel" a whole bunch.



The three places the system can leak at the master cylinder is the banjo fitting, under the reservoir, or around the plunger. If you reused the crush washers from the old hose, I'd start there. Again, this depends on where things are "wet".



As for the dragging, that could be the caliper or the master cylinder. If the piston in the caliper has dirt and/or corrosion on it, it can cause the dragging. Corrosion in around the seal can cause this as well. In the master cyclider, there are two holes in where the fluid leaves the reservoir. One of these holes is tiny, and if it were plugged up it would cause the dragging issues.



In saying that you have done the complete rebuild (caliper & master cylinder), did you reuse any of the old components or seals? Are you positive that the master cylinder was spotless before reassembly? Same question for the caliper?



In no way am I trying to say that the job was not done properly, just trying to explore any and all possibilities.
 

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Discussion Starter · #3 ·
I bought complete rebuild kits for each, and went through both with my motorcycle-guru uncle. He doesn't stop working on something until it's perfect, or as close to perfect as it can get. An example...I came to him wanting to turn my ignition switch into a thumb switch, and just zip tie it to my bars. He ended up fabricating a bracket for me, and I didn't even ask. He does not slack at all when it comes to fixing things. Cleaned everything, got rid of corrosion, etc. I distinctly remember popping out the piston and cleaning it out as well as replacing the rubber around it. If we did skip anything, it would have been known about. I was riding without a front brake for several weeks, and nothing was really rushed in rebuilding everything. When we first fixed it it didn't work well at all...turned out I was running a GL500 wheel. Changed that and it seemed to work fine as well as it's ever worked, which honestly was never very confidence inspiring....but I haven't really ridden enough other bikes to compare it to anything else. If memory serves, it was working similar to this before I crashed the bike, which is why I was without a front brake for a while. After I crashed I got a basket case front end off of a Deluxe from some great people in Va, and we couldn't get the front brake to work at all...even put on another master cylinder, and nothing. It was all because of the GL500 wheel, which I learned after rebuilding everything and getting it all spotless when I was home. The forks are still very iffy, one is most likely bent.



Nothing was reused but the hose itself, and maybe the washers that go with it. I don't really particularly notice it dragging when I'm riding, I honestly thought that I was just showing effort when pushing it because I was going uphill, and I was also quite a bit tired. Would popping the bike on the center stand, then adding weight to the rear to lift the front tire up and spin it be a good method of checking for front brake drag?



My uncle suggested that the leak is possibly coming from under the cap on the master cylinder, as that's where the moisture can be felt... no moisture can be felt around the banjo bolt. All of that is only several months old. We replaced the cap, reservoir, everything with brand new rebuild kits, nothing used. All but that hose.



If it turns out that I have to rebuild anything again, I'm just going to try and invest in another caliper that'll work with this disc and my master cylinder...or just another master cylinder and caliper. No sense in pouring more money into rebuilding something that I've already rebuilt once and not even a year ago when I can buy something that is much more effective anyhow.
 

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get that front wheel in the air and spin it around - it should spin quite freely



apply the front brake and release while it is in the air, should spin freely again - with NO drag at all.



did you replace the brake pads at all ???



replace the crush washers if there is any signs of leakage, take a bit of fluid out of the reservoir if it is too full or if not sealing correctly replace the diaphragm.



bad forks - I wouldn't be riding it if you think one is bent..



can you grab the front brake and pump the forks up and down - do they bounce back up or are they sluggish?
 

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Discussion Starter · #5 ·
Put brand new pads on when I redid everything. I figured that the braking feeling "weaker" after a bit was the pads being broken in. Figured after several thousand miles later that this was not the case.



http://cx500forum.com/index.php?/topic/4447-front-suspension-problems/page__p__50822 there's my thread on my front suspension problems. I have forks off of the '78 CX500, just haven't had time to put in the seals and change them over yet. So I probably won't even really do much with the front brake until I do that, I'm just trying to think now about what could be causing the issues. I've been riding on this front end for thousands of miles now. It's just really stiff and rough, I'm used to it.



Tomorrow I'll try spinning the wheel and see if the brake truly is dragging.
 

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Discussion Starter · #6 ·
Took a 50 mile trip to Orlando today all on interstate, and was able to notice a lot more about the problem.



The brake would be the least effective the less it was used...went a nice long 30 mile stretch without needing it, then when I did use it, I pulled it all the way to my grip and it did nothing. Of course pumping it a few times fixed it, but still....weird issue. It seemed to do this before rebuilding it too, just a lot worse. Earlier today I spun the front wheel to see if it was dragging....it looked like the pads were hitting the rotor, but not actually dragging it. I was told that this is totally normal behavior, but I'm not so sure.
 

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Leaking - have you fitted the seals/washers front and back of the fitting before fitting the bolt?



If you pumping then for sure you have air in the system, either by not fitting the seals as explained before or, you just have not bled it right...or both...



Keep the MC top off,fit a plastic pipe to the bleed nipple on one caliper, I borrowed my Batteries overflow pipe to the bleed nipple,as you pump release the nipple completely, then hold, close the nipple and let go of the lever, check the MC as you do this, the return will pump small airbubbles into the brake fluid....you have two holes, one big other pin size, big sucks in brake fluid to give you stopping power, the needle hole, is the return release pressure else your calipers won't release the pads...it will lock up.



Should not take you more then 10min with a twin caliper bleeding from scratch, I rebuild mine like you did from scratch...working like a charm.
 

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Discussion Starter · #10 ·
I've been thinking...is it possible that my problems are caused by my master cylinder being the tilted version for the CX500 Custom? I recently changed from the bucko bars to some nice normal bars. Seems like at certain angles, the fluid is so far over to one side of the cylinder, one of the plastic holes may not be covered in fluid properly.
 

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Discussion Starter · #11 ·
Let me elaborate on my idea of why the custom master cylinder may be the reason I'm experiencing problems.... the fluid isn't supposed to be over the full line, thus isn't supposed to be touching the cap, but when I'm parked or hell, even going down a straight road, the fluid is directly on the cap on one side....the side it seems like it's leaking from. On top of that, it looks like no matter how much fluid I put in it, it won't be able to always cover both holes in the reservoir with fluid, thus sucking in a bit of air from within the cylinder itself. I was thinking that maybe why I was seeing it leak while going down straight roads for prolonged periods of time was because the fluid was right on the cap where it shouldn't have been in the first place, and then with all of the vibration added on, it made it start coming out.



Could this possibly be it? I'm thinking that once I get my braided line, instead of using this rebuilt master cylinder again, I'm going to dig up a DRZ master cylinder that was given to me up in Virginia. Since the piston is smaller I'll get a better brake ratio (just read up on braking ratios again, holy crap, the standard brake ratio for all CX500s was horrible, no wonder my wrist starts hurting after a while in stop and go traffic) and I don't think that I'll lose any braking power from using it if I'm reading correctly. If that doesn't fix the problem (I don't see how it couldn't fix the problem, I see no issues with the caliper, it was rebuilt as well) I'm just going to give up and put on a front end from another bike. The only issue I have with that is I can't for the life of me find the bore of the DRZ400SM master cylinder. It's off of a 2008 if I remember correctly. Google is telling me it's either 11 or 13, which I think that both should work fine with the CX, but I'm not sure at all. I want a better ratio feel for sure, but I don't want to actually lose braking power.
 

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Discussion Starter · #12 ·
Ok, I installed the Chinese MC with the 12.7 Diameter after riding to work and having it lose pressure if I didn't pump it every half mile to a mile. Also installed the braided line. The new MC doesn't hold very much fluid at all and can't seem to pump up the brake. Oops. But it would compress the caliper after pumping a lot...it wouldn't close it much, but it would indeed close it. Movement would get rid of what little pressure was built. Hmmm. This makes me wonder...movement is what seems to destroy the pressure...sitting overnight did at one point, but I don't remember it doing it lately. Possibly the MC is too small but movement is making it even harder for it to work....or maybe we just didn't bleed it fully, which also is a possibility. I'm letting it sit overnight before putting the old one back on.



Also, possibly of note, the stock MC wouldn't pump all of its fluid out when it was completely removed from everything...we didn't want to remove the reservoir cap to drain the old fluid out, so we just pumped it, and it only pumped out some fluid but not all of the fluid that was obviously in there. My uncle tells me that this means "Something ain't right about it, and I don't want to open it up again to figure out what."



He also stated that it's a possibility that I have a warped rotor. I notice sometimes when braking (not all of the time) I get a lot of up and down movement on the entire front end, like going over a bumpy road. This likes to occur randomly. I do need to swap my forks out still, and always attributed this to the forks, but it may be possible that it's the rotor knocking the pads out of place. I do notice a somewhat quiet noise of a "tap" occasionally from the front of the bike, and when spinning the wheel the rotor does hit the pads some. I'm going to try and test runout tomorrow and see what I find.
 

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Discussion Starter · #14 ·
Are you sure it's bled completely? Doesn't sound like it is.


Not sure. However, this exact same thing happened when I installed a different 12.7 master cylinder shortly after I crashed last year...though that may not be a fair comparison as it had a broken stub of a lever, it was before my caliper was rebuilt (and it needed it BADLY) and when using the wrong wheel for the front end.



It was getting dark and I had screwed up my uncle's (and my) evening by starting to drill/tap this MC a bit later than we should've started. As always I thought that it "shouldn't take too long" and as always something went wrong and ended up taking us several hours. So those frustrations may have contributed to us not doing the job properly.



We used the traditional method of hooking a clear tube to the bleed valve and opening/closing the lever at various times all while adding more and more fluid. Sorry if that's a bad description, long day, my brain is fried, and I wasn't paying too much attention. It almost seemed as if after a while of adding fluid there'd be another pocket of air coming from nowhere. My uncle said that the best thing to do without wasting more time was to just ride it to see if heat from the caliper would make a difference, and it only made the slight difference I described above. Now it's sitting on its centerstand, with hope that the bubbles will work themselves out overnight. Maybe there's another method to bleeding, or maybe we can find a vacuum pump for not too much money (I'm broke, and he's cheap...not that I'd want him to buy something for me anyhow).



Also, what good does tying the lever to the grip overnight do? I wanted to do it just because I heard that it was a good idea, but my uncle said he'd never heard of it before, and that if I did that the return hole would be closed and that it doesn't seem plausible that air would float out that way. I couldn't think of a reasonable reason why to do it, so I just left it upright, and that's why I'm asking.



Maybe tomorrow when we're both in better moods we'll figure it out. It won't be hard to check runout though, so it may as well be ruled out just to cure my paranoia.
 

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Just another thought here....if the front rotor is warped, then it will push the pads back further when the lever is released. But if this were the case you would probably feel a "brake shake" when you used the brake.
 

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Discussion Starter · #17 ·
Just another thought here....if the front rotor is warped, then it will push the pads back further when the lever is released. But if this were the case you would probably feel a "brake shake" when you used the brake.


Well that's the thing, I do get a shake when braking, but more of a "bounce" than a "shake." It's hard for me to describe, and I have a hard time understanding people who try to describe it. I usually hear it's a "pulsing" and my bounce is a bit of a pulse in a way. I'm also quite paranoid so there's that too lol. It's also not consistent so it may just be my bad forks too, which is what I've been thinking it was to begin with. But the feeling can be described as the pads going away from the lever as the handle is released...or it's just losing more and more pressure as it's released. Maybe it just wasn't bled right either? I dunno. I'll learn when I go back to it today.



But, then again, it's always felt like it was doing this before and after rebuilding the caliper and MC, and even with different wheels, so the rotor is probably fine. It's probably just improper bleeding. It still isn't hard to check though, so I may as well do it.





Thank you very much for that, Shep. I'll maybe try that.



There was actually a thread started in general with nearly my exact same bleeding problems, new stainless steel line and everything. Crazy. So I'll play with those ideas as well.





Thanks to everyone posting help, I think I may be coming off as bitter in my posts, but I'm just not in a good mood because of this whole fiasco, and it's really thrown me off. I appreciate everyone's help, questions, and advice.



Oh, quick question, sorry if it's answered in the thread Shep linked, I'm late for work and only have time to type these (I'll read it later):



So taping the lever to the grip keeps air in the line, and then the line is bled the night after from the caliper? Sounds like a good idea. I'll get my uncle to do it this morning and when we bleed it this afternoon after work that may help.
 

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Cramer I got mine resolved.

My old master cylinder was leaning from under the reservoir.I did not want to buy a $40 rebuild kit when new MC was $35 (plus shipping) so I just bought the MC.

I tilted my MC forward (banjo bolt toward the ground) so the holes in the reservoir were higher than the banjo bolt. Then I picked up pressure immediately. After that it was a straight forward bleed. I like to use Sheps method. You know clean clear glass jar with fluid in it and a clear hose going to the jar. Then pump until all bubbles stop.

I am going to go ahead and secure the handle back but with how hard the handle got I do not think it is an issue!
 

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Discussion Starter · #20 ·
Looks like the Banjo is below the level of the holes, so that isn't an issue. I'm going to be sure to double check for leaks and stuff tomorrow. I know that this is 3:20 AM, but I'm posting this as if it was still 4-22-11 so bear with me.



When I first got to it today the MC had a "bit" of pressure, more than yesterday, but still not enough to really stop the bike properly. I decided to bite the bullet and buy a Mityvac. After several hours and two bottles of DOT3 fluid, the only thing I was able to achieve was making it lose a bit of pressure. Ugh. At one point I couldn't even get fluid to come out of the bleed valve, I determined that to be my improper use of the Mityvac....bled it more using a more proper method, went back to the traditional method, and could only get minor pressure. More than the first night, but nowhere near where it should be. When riding it home I noticed that it was very similar in nature to my last MC, except with a lot less pressure/power. The more I pumped it, the more it would stop the bike, and not touching it for a bit would reset it back to its lowest pressure. The best I was able to get it still wasn't quite as good as the old MC.



I ziptied the handle to the grip, in desperate hope that tomorrow it'll be working fine, and money will run from the skies, as the bike achieves 150 MPG and 0-60 speeds in less than a second.



No, I'm not bitter, I just have a weird sense of humor.



Haven't been able to check the runout of the disc yet, I'll see if I can do that tomorrow.



Here are a few questions: I was told to bleed again from the caliper after leaving the handle ziptied to the bar overnight. Does this mean open the bleed valve while the handle is still pulled ziptied, or should I pump it a few times first, then bleed?



If I were to buy a syringe to reverse bleed, would that mean I'd need to completely drain the fluid out first, then pump new fluid in?



Would it be worth it to invest in a "speed bleeder" valve?



For the method in which the master cylinder is covered by a hand, the lever is pumped, and the bleed valve is open with a tube in it under old fluid, would this work using the Mityvac? I'm trying every method that I can think of. I've got to get this thing to work somehow.
 
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