Break noise, but not a squeak - Kawasaki Vulcan 750 Forum : Kawasaki VN750 Forums
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post #1 of 12 (permalink) Old 06-25-2007, 03:17 AM Thread Starter
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Break noise, but not a squeak

First off, Thanks for having a wonderful forums. I have read through all 9 pages of this section and didn't find anything that was like what I have.

2 weeks ago I bought a 2004 Vulcan 750 with only 4110 miles on it. I love the ride and feel of this bike. I thought I got a great deal for $3900, but....

I'm having a front break problem. When I apply the break above 30 mph, I hear a sound that sounds like fluid gurgling through a straw. I thought it might be a break line, so I cleaned everything. Even took the calipers off and cleaned them up too. I did find that the right side (as your sitting on it) bleed valve had some fluid in it's cap and the cap has a small whole in it. Tried tightening it up a bit, but that didn't matter. After cleaning everything. I went out to the bike the next morning and found bright orange fluid on the front tire but no where else. Which is the same as what's in the MC. The pads are worn incorrectly, the left side pads are more worn than the right, but still within limits. The break lever feels good and accually even firmer since I tightened up the bleed valve.

I have had this problem from day one. If this is going to be an expensive fix, I have been contemplating giving back the bike. I really want to keep this bike, but can't see that I should get stuck with a major repair on a 2 week old purchase with less than 4200 miles on it. If I take the bike to the local dealer, I know it's not gonna be cheap. Breaks are something I won't play around with. They better be right, or you'll be in trouble.

Can someone please tell me what could be the culpret here. Could air in the system cause this kind of gurgling sound? Is it posible that the wholes in the discs could make the noise? Am I just being to critical of a big purchase?
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post #2 of 12 (permalink) Old 06-25-2007, 07:22 AM
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Welcome! Sounds like you did get a good deal, and hopefully this'll be an easy fix. My first thought is that there's something wrong with your brake lines, particularly given that the left and right sides are wearing differently. There's a linkage under the triple-tree where the right and left lines separate - I'd be looking hard at that and see if there's a split in there (if you're getting fluid on the ground, you've got a leak somewhere in there). I haven't yet priced out brake lines, but maybe someone else here can give you a guesstimate if that turns out to be the culprit. The brake system is pretty simple and self-contained, so don't throw the 750 baby out with the brake fluid!!

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post #3 of 12 (permalink) Old 06-25-2007, 10:32 AM
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I think you might be able to fix this pretty easily, I'm hoping anyway.
You mentioned orange fluid? Your brake fluid should be almost clear. Probably you have dirty fluid, possibly from the right side bleeder valve being leaky. I would purge the fluid. It's an easy job. Get some small clear flex tubing at the hardware store. I think 1/4" or the next size smaller will do. If it's flexible, it will stretch over the nipple on the bleeder valve. Put your bike on the centerstand, and remove your MC cover. Wrap a rag around the handlebar to keep any spillage from splattering, and probably put a towell over your gas tank to keep the same from getting on your painted surfaces. Brake fluid can be pretty bad to paint in a short while!

Take a clear glass bottle or jar and put some brake fluid in it, enough to keep your tube submerged. You can tie a heavy bolt or nut on the end of the tube with a wire tie to help keep the end submerged. Fit the other end over your Left side bleeder valve nipple. (left as you sit on the bike), as this I believe is the longest side, and it helps to bleed the longest side first. It may not matter though. Make sure your MC is full of fluid to the top full line. During this process, make sure you have fluid in the MC and that it doesn't run dry, as it will introduce air into the lines and you have to start over.

Use a 10mm open end or box end wrench and put it on the bleed valve but don't loosen it yet. Squeeze the brake lever all the way in, slowly, so it doesn't spirt fluid up in the air. (The manual says to do this with the cap on the MC to keep dust and debris from getting in there, so use your own disgression here. If it's windy and dusty, maybe that's a good idea. If it's calm, leave it off so you can see what you are doing!) While the brake lever is compressed, hold it, and with the other hand, open the bleeder valve just enough for the compressed fluid to squirt out the tube, then tighten the bleeder valve, then let up on the brake lever. Repeat this process over and over, checking between times to make sure you are keeping the MC full of fluid and not letting air into the lines. Watch the tube and repeat this process until you see nothing but clear DOT4 brake fluid coming out of the tube, and no air bubbles. Once you have clear fluid and no bubbles, tighten the bleeder valve one last time and replace the rubber cap over the nipple. Put the tube over the nipple of the other bleeder valve and repeat the process, again until you see nothing but clear, non-bubbly fluid coming out. Tighten that bleeder valve one last time, replace the rubber cap and top off your master cyl and replace the cover. You should be done, and your brakes should apply evenly.

I feel like it is possible that your brakes were applying more to one side because of the bleeder valve being slightly open on the one side. Hopefully this will solve your problem. Good luck!

Kyle, TX member #707 VROC#19556
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post #4 of 12 (permalink) Old 06-25-2007, 09:38 PM Thread Starter
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Thanks for the replies. Fergy, are you saying that dirty break fluid will cause the gurgling noise? That is the part that is puzzling me. I do understand the whole leak causing low pressure and uneven wear of the pads, but if it was that bad of a leak, then the Master Cylinder should have been bone dry when I opened it up. It was low, but not lower than the low level amount.

Quick question... If the break system is supposed to be a closed system, how does the fluid change to an orange? Is that because of the heat at the calipers?
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post #5 of 12 (permalink) Old 06-25-2007, 11:12 PM
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Brake fluid will absorb water from the air, it can change brown to orange color depending on if there is rust or other contaminents in it.
You could have had water in the calipepr boot that leaked out also, did it feel oily or not.
Make sure you use DOT 4 fluid.
That is what it says on the cap if you read it.
You can also Gravity bleed the system by doing the same as Fergy said but not pumping the brake, let gravity flow the fluid down.
I just did mine today, after 2 years it was dirty and brown/orange in color.
Hope this helps

Chad Falstad "Hawk"
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2001 Nomad 1500 Sold March 2012
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post #6 of 12 (permalink) Old 06-26-2007, 10:00 AM
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And, it probably picks up some of the chemicals in the rubber hoses and reacts with them, as well as probably getting heated up some etc.
Don't know about the gurgling noise, but there is a slight noise that some of us can hear when we apply the front brake that sounds a little like a tiny playing card being against the spokes of a bicycle, like we used to do when we were kids on our bikes to make them sound like motorcycles. It's probably the sound of the vent holes making contact with the pads as we apply the brakes, but to me it's almost inaudible.

I'd bleed the brakes, get new fluid in there and make sure you don't have any leaks, then see how it goes.

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post #7 of 12 (permalink) Old 06-26-2007, 10:37 AM
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I agree the most important part of our bikes is the front brake. I tossed the rubber lines in favor of stainless steel ones for under $100 delivered.

Purged all old fluid and put in new brake pads ($35).

Front brake is way better than stock now. The stainless lines do not expand like the rubber ones will over time.

If you get a gurgling sound, you've got air in the system somewhere. You could start with flushing out the existing system, open the master cylinder, open one bleed screw and pump new fluid through until it runs clear. Repeat for the other bleed screw. Top off the master cylinder. Bleed both calipers until you get a good brake lever. Then, tie the brake lever as tight as possible and leave for 24 hours. Bleed one more time, both calipers.

If you still have the gurgling noise, your master cylinder is bad.


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post #8 of 12 (permalink) Old 06-28-2007, 03:46 AM Thread Starter
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Ok, so I bought new pads ($65) Jon, I'm jealous. I drained all the old orange stuff out. Cleaned the MC. Turns out, the orange color was from the 2 MC cap screws. They were rusted. The rust was all over the inside of the MC bad enough that I was surprized that the holes weren't clogged. Anyway, Took the bike around the block and the sound is still there. So, now I do believe that I have bad lines, but I don't see any fliud on the lines, just on the tire. If the lines were truely the problem, then they should be wet. Right ???

Here's a question.... Why when I squeeze the break lever do I hear the rubber thing inside the MC moving? Is that telling me that there is still air in the system? I didn't hear it before the flushing, but now I do.

Funny, I used to work in a body shop and have rebuilt many a car and quite a few bikes, but the funny part is that I really haven't messed with breaks too much. They seem allot simpler on cars than on bikes. Maybe because you have more time and can build more pressure on a car than with a bike.

My guess is that the previous owner who only drove 3900 in three years must have let it sit so long and didn't pay any attention to these kind of problems. I have other problems that I will post in the appropriate threads.

Thanks to all for helping me. I hope that I have some knowledge that can be of use to any of you too.

edit.... can someone explain the whole tieing of the lever over night thing to me please. What's it for?

Last edited by Maj Lee Screwed; 06-28-2007 at 04:02 AM.
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post #9 of 12 (permalink) Old 06-28-2007, 11:07 PM
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Tieing the lever down overnight will cause all the pesky little airbubbles still stuck on the lines to rise to the top. There is a scientific definition and I've read it on here somewhere, mine is just the bottom line answer. This usually works really well and I do it whenever I bleed the brakes. Just leave it on overnight after you bleed them and you'll be good to go! Well, should be.

And what rubber thing inside the MC are you talking about? The little diaphragm under the cover? If your hearing that then your leaking the fluid somewhere, or didn't put enough in, and the pressure is trying to suck the diaphragm into the fluid hole. If you bleed them, make sure you refill the reservoir to the top because it will suck in more fluid once the tire spins and you actually use the brake.

Hope this helped!
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post #10 of 12 (permalink) Old 06-29-2007, 01:55 AM Thread Starter
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yeah tyger, that did help me understand what it's for. Thanks for the help. I must not have put enough fluid in, I didn't want it to spill out. LOL. I will. And yea, I do rap up around the MC before removing the screws. Man, that stuff will even eat life cereal.
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