Front brakes are sticking.

So I just put on new tires and I took the wheels off to do so. Well, I noticed after I got it all put together that my bike was harder to push around. The rear wheel spins fine, but the front wheel barely spins (front wheel in air). As soon as I push to rotate it, it just stops and doesn't even make a full rotation. I pulled the calipers off and spun the wheel and it spun freely, so the bearings and axle were fine. I decided to get a screwdriver and compress the brake pistons and put them back on and it seemed to make it better, but its still not to where it should be. Are the rotors interchangeable or is there a left and right on the front? Any idea what the problem could be?
 
Did you get the axle spacers (collars) mixed up side to side. I can't remember if they are the same length. OK never mind, according to the parts fiche they are interchangeable.

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Gen 1

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Gen 2

I had a similar issue with my fronts this season (different bike) and after changing the pads and reassembly. I gave the brake lever a hard squeeze and they still dragged a bit after release (I could still turn the wheel easily by hand, it just would not spin freely). I took the bike for a short run and used the brakes hard a few times and the problem was gone.
 
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I tried about everything I could think of besides taking out the caliper pistons and sanding them/cleaning them. Still wont spin freely, takes effort to turn. Wheel is installed the right way, arrow pointing forward on both tires and wheel.
Here's what I've done:
-Removed pinch bolt, loosened axle, set it down, rolled around front and back, grabbed the brakes hard. I saw this on another forum and supposedly it sets the grease fittings in to make sure they aren't binded.
- Pulled the calipers off, compressed the pistons with pads still on with a screwdriver. Seemed to work well for the first few grabs of the brake, then it went right back to being stuck.
-Sprayed brake cleaner on pistons with pad still on.

Any ideas besides taking pistons out and cleaning them? If I did this, would I have to bleed the system?
 
I tried about everything I could think of besides taking out the caliper pistons and sanding them/cleaning them. Still wont spin freely, takes effort to turn. Wheel is installed the right way, arrow pointing forward on both tires and wheel.
Here's what I've done:
-Removed pinch bolt, loosened axle, set it down, rolled around front and back, grabbed the brakes hard. I saw this on another forum and supposedly it sets the grease fittings in to make sure they aren't binded.
- Pulled the calipers off, compressed the pistons with pads still on with a screwdriver. Seemed to work well for the first few grabs of the brake, then it went right back to being stuck.
-Sprayed brake cleaner on pistons with pad still on.

Any ideas besides taking pistons out and cleaning them? If I did this, would I have to bleed the system?


Found out after tonight that the calipers need rebuilt or replaced. The seals are literally poking out and dry rotted out of each piston. Only one side (pistons) is pushing when brake is applied which makes sense why they were sticking (no resistance from the other side). I may either rebuild or replace.
 
Found out after tonight that the calipers need rebuilt or replaced. The seals are literally poking out and dry rotted out of each piston. Only one side (pistons) is pushing when brake is applied which makes sense why they were sticking (no resistance from the other side). I may either rebuild or replace.

Good that you found that now. I would just buy the seals (pistons if they are grooved) and some fluid and rebuild. Ther really isn't much to it. Just pay attention when you are taking them apart (take pictures as you go for refference). There is lots of information out there and bike brakes are as simple as they get.

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Does loosening the bleeder screw release the brakes? If not the problem is in the caliper. If it does then work your way to the master cylinder loosening the fitting to bleed off pressure. Could be a hose. The first thing to figure out is if it is hydraulic pressure holding them on or some mechanical issue at the wheel.

Just to note that all disc brakes have some drag. If you can't feel it when pushing the bike or riding you might ride a short distance and stop with just the rear brakes and then see if it has freed up.
 
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How much drag would you say is normal? I tried just loosening the bleeder screw's and while they were open the wheel still stuck. I can maybe get one revolution if I throw the wheel.
 
I have about 1000 miles on my double H sintered pads and I just checked it and I can get about 1 revolution if I spin it real hard. I put 450 miles of that on them today in 7 hours with no sign of trouble. I would say you are OK.
 
Yeah, I can only get about one rotation if I try to spin it real hard. Would you say your pads are worn in and aren't fresh anymore? If so, this makes me feel alot better. Not used to having this much drag on a bike or car.
 
I love rebuilding brakes... very satisfying.... It can be difficult to determine the cause of a binding brake.

Sometimes it is the piston not retracting properly. If I have read this thread correctly you have rules this out by rebuilding the calipers. That should also rule out any problems with the fluid as you would have replaced that at the same time. I assume you've also checked the master cylinder... there's a spring in there that's very annoying to get back in but it's damn important for releasing the pressure.. if that's weakened and the piston it pushes isn't being pushed back out then you have another potential cause.

On these bikes there are floating discs. If they have been replaced with fixed ones then they may have warped and that could make them stick too, but in that case you would feel is as a pinch followed by free play followed by a pinch unless they are so warped they go from pressing one pad to the opposite pad .... which you'd undoubtedly feel as horrible judder under braking.

If you can't get them to feel right to your satisfaction, go to a dealer. Brakes will safe your life and it's best to get professionals involved if you are in the slightest doubt about them.
 
I love rebuilding brakes... very satisfying.... It can be difficult to determine the cause of a binding brake.

Sometimes it is the piston not retracting properly. If I have read this thread correctly you have rules this out by rebuilding the calipers. That should also rule out any problems with the fluid as you would have replaced that at the same time. I assume you've also checked the master cylinder... there's a spring in there that's very annoying to get back in but it's damn important for releasing the pressure.. if that's weakened and the piston it pushes isn't being pushed back out then you have another potential cause.

On these bikes there are floating discs. If they have been replaced with fixed ones then they may have warped and that could make them stick too, but in that case you would feel is as a pinch followed by free play followed by a pinch unless they are so warped they go from pressing one pad to the opposite pad .... which you'd undoubtedly feel as horrible judder under braking.

If you can't get them to feel right to your satisfaction, go to a dealer. Brakes will safe your life and it's best to get professionals involved if you are in the slightest doubt about them.

Hi Paulcee,
Recently my front brakes seems losing pressure, at times i am able to pull way back to near 1 cm gap from handle bar grip. I have done bleeding twice but same issue. I sighted oil wetness at master cylinder piston dust cap, I assumed the oil being pushed down got slipped through the piston seal on master cylinder and hence gonna replace them.

My question is, I am able to grab a set of piston with seals on but I measure both oem and the aftermarket , after market seems 10mm longer than oem. The spline part almost equivalent just the part after circlip protrude outboard is longer. Will this cause any issue? Both are the same 14mm.
 
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