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Old 08-23-12, 04:36 PM   #1
TrebelC
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Problems with my disk brakes-Trek 4300 Disc

Hey guys so I just bought my 2012 Trek 4300 Disc yesterday. I rode it for about 10 minuets at max. Than today I rode about 18 miles. Early on, but not yesterday only today, roughly 5 miles in I noticed my left front brake pad is constintly against the disc. Although, I can hear the rubbing, the wheel still spins very freely. Is this an issue whatsoever?
P.s- I use my front brake 95% of the time.
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Old 08-23-12, 04:46 PM   #2
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First thing...good on you for using the front brake so much. So many people out on the trail sliding the back wheel around...bleh!

It's normal for a lower line bike to have inconsistant pad retraction, lower tolerances in hub axles and bearings, and other random things that drive me crazy. Even mid-level brakes like Avid hydraulics will occasionally have this issue of inconsistancy. My elixirs are doing fine though.

Best thing to do is loosen the caliper bolts just enough that the caliper will move laterally...clamp down on your front brake...hold tension...tighten the caliper bolts. This should center the caliper.

There are occasions that this doesn't work...in these cases, you can either use a couple of shims (one on either side of the rotor between the pads and rotor)...or you can just eyeball it to center.

If you find this happening on a regular basis, it would help to localize the issue. If you're running mechanicals, it's not an inconsistancy in pad retraction b/c only one side moves. If you're running hydraulics...it could possibly be inconsistant piston retraction. Just look at it really closely when you let off the brake.

If you find that it's not the piston...then you need to decide whether or not it's worth it to upgrade to a more expensive front hub. You can find some pretty decent front wheels laced to an XT hub for a fair price on eBay, bicyclewheelwarehouse, and other online vendors.



Make sure your front skewer is tight enough btw, LOL.
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Old 08-23-12, 10:21 PM   #3
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Best thing to do is loosen the caliper bolts just enough that the caliper will move laterally...clamp down on your front brake...hold tension...tighten the caliper bolts. This should center the caliper.
Thanks a lot for the advice Ed. Although the only problem though i cant find the caliper bolts. What do they look like? Becasue my on the mechenism there are two on the back side(facing the spokes) and 2 on the top. One biger than the other. I would put pictures on but my camara shoots HD and the file is "to large" so I cannot.
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Old 08-23-12, 10:42 PM   #4
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I just looked up your bike, it has Hayes Dyno Sport hydraulic disc brakes on post mounts.

Look at the caliper from the left side of the bike. You will see two bolts that secure it to a bracket, which are forward and rear of the caliper. The bracket has two similar bolts which mount it to the fork (front) or frame (rear).

Loosen the two bolts that attach the bracket to the caliper. Then follow everything Ed said.

Make very, very sure not to squeeze the brake lever if the caliper is not on the rotor, such as removing the front wheel. This will probably cause the pistons to stick in an extended position and then you would need to open the bleeder to force them back in. Put the plastic travel spacers in the calipers, or if you don't have them, use a piece of cardboard approx 1/4" thick.
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Old 08-24-12, 09:30 PM   #5
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Thanks guys a lot. I got them repostitioned so now its all in perfect shape! Thanks again!
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Old 09-30-12, 07:27 PM   #6
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Trek 4300 Disc brake rub problem > Solution

So I had this problem today where my brakes were locked up on my Trek 4300 Disc. I realized the only thing that had changed was the weather which was about 20 degrees hotter then yesterday and that got my wheels turning . After trying the loosening caliper bolts technique helped just a little I figured why not cause the disc to expand as much as poss by applying heat with a heat gun then loosening the caliper bolts and while holding the brake lever tighten them back up !? Well it seemed to work great ! And Now as the weather changes the worst that will happen will be more "play" in the brake lever when its cold which is a lot better then a locked up brake ...? Be careful when your heating your disc with a heat gun as not to melt the paint on the rim or caliper . You really just need to heat it to about 150 degrees F which will be about the hottest the would get naturally , and this can be accomplished with a blow dryer or even a space heater . Good luck I hope this helps somebody !
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