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Front Wheel Issues

  #1  
Old 04-21-2011, 02:58 PM
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Default Front Wheel Issues

I had my front tires replaced last August, roughly 2500 miles ago. About a month and a half ago I started hearing grinding / rubbing noises and the bike was hard to push. So I investigate and the front left rotor is rubbing against the brake housing as if the entire wheel was shifted slightly to the left. So I take the wheel off and inspect the rotors and I can't find any warping. So, when I put the wheel back on I put small socket wrench to hold the fork about 1 mm from flush with the collar but exactly in line with an indented ring on the axle. Everything was fine until about a week ago when I started hearing high pitched "moans" when traveling at low speeds and the bike is again hard to push. I doesn't look like the rotor is rubbing against the caliper housing, but the front brakes are extremely tight and there's a lot of resistance when spinning the wheel by hand (bike is on stands). When I spin the wheel slowly it produces the moans.

Any suggestions? Would the earlier problem have anything to do with the brake pads being exceptionally tight? The back wheel spins fine (when the brake lever is not pressed). Do I need to flush the front brake lines? The pads seem fine and have been on there since I bought the bike last January, and no, they are not warn, just very tight when the levers are not even being pressed.

Thanks.
 
  #2  
Old 04-21-2011, 04:31 PM
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How many miles are on it? Sounds like the wheel bearings maybe bad. Take the calipers off so there is no chance they can rub. Spin the wheel if it still makes any noise it is the wheel bearings.
 
  #3  
Old 04-21-2011, 06:41 PM
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Originally Posted by slowride View Post
Sounds like the wheel bearings maybe bad.
That's what i'd guess too.
 
  #4  
Old 04-22-2011, 01:28 PM
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The bike has 17,500 miles on it. I took off both brakes, both of which didn't really want to come off. The wheel spins pretty well, although I could hear some "marbles in a bag" when I put my ear close to the axle. Not sure if that was there last time I had everything off since I wasn't really listening for it. One of the seals may be leaking a bit but I don't think that's my current problem, but yet another thing to fix. The calipers were a bit hard to push in at first, but got easier after they went in and out a few times. I watched as I pressed them and both sides seem a bit off balance, ie, don't press at the same rate. On the left side the two calipers are really bad, one might be a bit stuck, but it is stuck at the depressed position not out. Maybe that's causing all the others to be too tight? I suppose I need to disassemble and clean them at the very least.

Any other suggestion? I appreciate the feedback.
 
  #5  
Old 04-22-2011, 06:53 PM
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I'm guessing from the description, that the calipers aren't 'floating' properly.
There are 2 pins that the calipers ride on with rubber boots around them. If the grease is all gone they will hang up and not back-off the discs like they should.

It is fairly easy to dis-assemble and clean and re-lube them (without having to bleed the brakes). I would go ahead and replace the axle bearings at some point, as they may have been damaged by the rough treatment. After you get the calipers rebuilt, ride it and see how it feels. After that, if you still have a chatter but only while braking, you may have a warped rotor as well. If you don't have a dial indicator, but want to check a rotor, lay it on a piece of hvy glass. Run a set of flat guages under the edge all around looking for the high spots (if any). Double the thickest guage you can slide between the glass and the rotor, anywhere around the circumfrence, is your run-out.

Good luck, Ern
 
  #6  
Old 04-22-2011, 08:27 PM
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Originally Posted by MadHattr059 View Post
I'm guessing from the description, that the calipers aren't 'floating' properly.
There are 2 pins that the calipers ride on with rubber boots around them. If the grease is all gone they will hang up and not back-off the discs like they should.

It is fairly easy to dis-assemble and clean and re-lube them (without having to bleed the brakes). I would go ahead and replace the axle bearings at some point, as they may have been damaged by the rough treatment. After you get the calipers rebuilt, ride it and see how it feels. After that, if you still have a chatter but only while braking, you may have a warped rotor as well. If you don't have a dial indicator, but want to check a rotor, lay it on a piece of hvy glass. Run a set of flat guages under the edge all around looking for the high spots (if any). Double the thickest guage you can slide between the glass and the rotor, anywhere around the circumfrence, is your run-out.

Good luck, Ern

+1 wheel bearings are relatively cheap.
 
  #7  
Old 04-23-2011, 05:43 PM
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  #8  
Old 04-24-2011, 04:53 AM
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Originally Posted by MadHattr059 View Post
I'm guessing from the description, that the calipers aren't 'floating' properly.
There are 2 pins that the calipers ride on with rubber boots around them. If the grease is all gone they will hang up and not back-off the discs like they should.

It is fairly easy to dis-assemble and clean and re-lube them (without having to bleed the brakes). I would go ahead and replace the axle bearings at some point, as they may have been damaged by the rough treatment. After you get the calipers rebuilt, ride it and see how it feels. After that, if you still have a chatter but only while braking, you may have a warped rotor as well. If you don't have a dial indicator, but want to check a rotor, lay it on a piece of hvy glass. Run a set of flat guages under the edge all around looking for the high spots (if any). Double the thickest guage you can slide between the glass and the rotor, anywhere around the circumfrence, is your run-out.

Good luck, Ern
I'm gonna guess this isn't the front wheel bearings at 17K. Bearings are far, far down the list of things that fail, given Japanese quality control.

I'd guess the pistons aren't withdrawing into the caliper bores and that's where I'd start. Pull it all apart, clean up the piston and put in new seals.

As for the rotor warpage, maybe. But a lot of warpage is actually due to material deposition from the pads, which can be cleaned up with solvent and abrasive. (Sometimes...) But this sounds worse than that.

I'd also check the rotational arrow on the wheel to make sure it's installed right.
 
  #9  
Old 04-25-2011, 07:46 AM
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Thanks for all the suggestions. I have new bearings on the way, everyone I've talked to said if you can hear them at all they're probably going bad and they are relatively cheap to replace. I followed the procedure in the service manual for putting the wheel back on and the arrow on the tire was facing in a counter clockwise direction (forward at top, backward at the bottom). All bolts were tightened to their proper torques. I suppose I did pinch the left fork out about a 1mm so that the it lined up with the mark on the axle and the rotor (left) wouldn't rub against the caliper. The only reasons I can think it didn't line up was the bearings were not seated properly so the spacers didn't hold it center between of the forks or the forks themselves are a bit twisted. I was planning on cleaning the calipers and / or replacing the brake fluid, are new seals necessary? Should I order some now or inspect them first?

Thanks.
 

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