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Not a sexual innuendo
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Discussion Starter #1
hey,

just getting my bike ready for the season... fresh problem..

so the brakes were dragging on the front tire, so i just rebled the system hoping it would fix it. It didnt; it still drags... so i take it for a ride hoping it will just sorta fix it self after a few brakes, but it didnt.

It makes this weird shuddering sound when i brake hard, and a constant squuek , squeek , squeek as the wheel rotates. I left it outside covered with a tarp for the winter... Im about to take the whole thing apart.

Anyone got any ideas what it could be?
 

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Lightly seasoned...
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I had some dirt/debris in my brakes when I brought the bike back on the road after 8 week hiatis, just bombed up and down the street a bunch braking hard repeatedly to crunch it all out and get rid of any bubbles in my lines from topping up the brake fluid.

My best bet is that its one of the calipers sticking or caliper head is imbalanced... little cleaning and lube of its movement (not the actual caliper themselves), clean the disk off, and should get things back and working easily enough.
 
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if it is an on/off squeak, one of your rotors may be warped.

you may also need to chamfer your pads. clean everything with brake cleaner at the very least.
 

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I was guessing a warped rotor, too.
 

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Not a sexual innuendo
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239 Posts
Discussion Starter #5
mm it was fine before though. I dont think sitting around it could get warped.

It is an on/off squeek

i think wolf nadrid may be right. I took off the front fender and went for another rip and it was a bit better; i dont think it was affected by the front fender though, even thought its cracked.

Is it possible some water got in the bearings? and if so, will just some regular use take care of it?
 

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Fastronaut
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Sounds like a seized piston in a caliper,

Do you know how to back bleed the brake?
 

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It has Hondaitis , tape the brake caliper with a rubber mallet and see if the squeeking stops. If it's that your going to have to dissasemble the caliper and clean out the white flakes under the caliper seal.
 

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Not a sexual innuendo
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Discussion Starter #9
"back bleed" the brake? uh i dont think i know how to do that... what is that?

rubber mallet eh, ill try that.

mm ya possible seized piston. Sounds probable except i just rebuilt them last season... think half a year outside could do that?


ALSO- if you have the front wheel raised, how much drag is normal/acceptable? when i spin it hard, it spins for maybe 2-3 seconds
 

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Fastronaut
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If you can rebuild a brake or caliper then you can back bleed.

Turn the bars so the front brake reservoir is level and wrap a rag or sweatband around as you can spill fluid during this. I keep a spray bottle of rubbing alcohol and a hose around in case I have to quickly clean up a splash.

Take the cap off and check the level of the fluid, and the colour while you're at it. Then move down to the calipers. Get a small bar and pry back the pads from the rotor. I do mine from the back side so that I don't damage the pad material, work the backing plates by the fixing pins. While you do this you'll be pushing the fluid back up into the resi, so only do one side at a time or you'll run the risk of overfilling.

Once the pads are back grab the front lever and pump it. There will be no resistance to start, and then pressure will build. Watch the pistons and see if the move equally. Move to the other caliper and repeat. Since the pistons are self centering if one's seized the other will move further and compensate. That could result in a scrubbing sound.

Back bleeding's just a quick bandaid fix so if something is seized it's time for the real fix. And of course button it all back up and wipe it clean when you're done.

The pads have to scrub the rotor. I know there are guys out there who spend hours with spacers lining up the caliper so it's dead even but a little drag isn't a big deal in my eyes. If the pads didn't have close to zero clearance then there'd be a mushy feeling to the brake until the pads contacted the rotor.
 

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chances are if you have siezed a caliper the constant dragging heats up the rotor and warps it , if you already rebuilt the calipers properly , and t still drags in spots then you warped the bastard . perhaps its still dragging because you didnt acutally fix em ? if you cant bleed the brakes i doubt you can re buld them properly. but who knows
 

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Discussion Starter #12
?? i can bleed the brakes properly... where did i say i couldnt... i just never heard of the term back bleeding

thnx danke


il get back to you guys with what fixed it
 

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What bike is this on? YOu list a 97 Honda VFR. Does that bike use the 4 pistons in the fixed body calipers or does it use the old two piston Nissins with the floating body?

If it's the floating body then you gotta clean and re-grease the floating pins that allow the body to float back and forth.

If it's the 4 piston one then there's a trick I've used for tight pistons that are not quite in need of a full tear down and rebuild.

Unmount the pistons and pull out the pads. Spray out the area around the pistons liberall with a can of brake cleaner spray. Now here's the tricky part. Pump the lever to push the pistons out a short bit. Watch for the ones that do not move. Hold back the ones that do move so you force the sticky ones to move. PUmp them out of their cylinders so about a 1/4 inch of side wall is exposed. This will take about 10 to 15 strokes of the brake lever so don't get all worried. Now clean off any crud you find on the sides of the pistons and check for any signs of bad scratching or possibly rust pitting in the chrome finish. of the piston sides. Now coat the sides of the pistons with a light rub of fresh brake fluid and push them back in with your fingers. Watch that when you do this one of the others does not try to pop all the way out. Go slow and easy. Now pump them back out again. Repeat this in and out about 2 or 3 more times. After the second push back you may want to bleed the lines a bit more while the pistons are fully in since any stagnant fluid in the caliper will have been pumped around and mixed with the new fresh stuff and the mix of new and old will be up in the lines and available for flushing out.

After 3 or 4 cycles of this pumping out and pushing back in you should find that the pistons all move together or that the sticky ones take a lot less effort to get moving. You can feel this difference in the amount of force needed to hold back the "eager" pistons. Lubing the pistons while extended with some fluid ensures the seals get a bit of help. Finish it off by pushing the pistons back in and brake cleaner away any residue of fluid from the pistons. Reassemble the pads and remount the caliper.

Do the same for the other side. And next time don't store it outside if you can possibly avoid it. At least if you do put a 40 watt light bulb up under the cover but still low so the heated air keeps the inside of the cover warmer than outside and dry to boot.

If none of this works out then you have a seal that is getting old and is in need of replacement. Also if you have the dreaded linked brakes then you'll need to modify the procedure to catch the front system pistons as well as the rear system pistons that are in the front calipers. But the theory is to pump them out, clean, lube with fluid and then cycle them a few times to free them up in the seals. If the seals don't come back then replace the seals and any badly scuffed or pitted pistons.
 

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Not a sexual innuendo
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Discussion Starter #15
4 piston system (2 each). I will try that, sounds like it will work. Will that also solve the weird noise at every rotation of the wheel? , Bruce?
 
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