Front Disc Brakes
 

The cylinder that forces the brake pad up against the front brake disc does not retract far enough to take all the drag off the disc. Is this a brake fluid problem or something else?

I would flush the fluid out and fill with some DOT 5. Give that try to see if it helps any. If not it is likely that the piston is sticking.

The brake fluid that comes in these bikes is mediocre at best.

Allen

Most of these will have a small drag on the disc at all times. With the wheel off the ground, spin it and if you can get one revolution that is not to far from normal.

You may not be able to turn it at all but I could not tell form your post. If that is the case do what the katoranger said! A great idea on any new china bike.

Three China bike rules.
1, If it's a Chinese fluid drain it and replace it.
2, If it's a chinese rubber product, Replace it soon!
3, If the bolt is put in by a Chinese worker, Loctite it and tighten it.


The oil is probably made from whale blubber, The brake fluid is recycled from sewer water and the rubber will melt if it's ever is exposed to anything but it's natural environment....And the bolts fall out to let You know the bike needs love :D

The job of returning the piston back into its cylinder is the rubber seal around the cylinder. This distorts on purpose and acts like a return spring.

The brake fluid under pressure forces the piston to slide out of the caliper. This action deforms the seal in the direction the piston travels. When releasing the brake pedal the deformed seal will pull back to its original shape and pull the piston with it, this action will release the brake pads from the disc.


http://www.telecable.es/personales/a...lliperseal.jpg

I just learned something new. Great.

Allen

i would also check the pins on the caliper to be sure they are sliding smoothly your auto parts will have some caliper grease or brake grease, dont use regular grease

at least your cylinder IS forcing the pad onto the disk, no matter what i do to my front brake it never seams to...just......work really :?

strip the brakes rite down to bits remove pistons springs pins ect clean everything thorghly (spelling lol) bave every thing in petrol rince with water let it all dry then reasemble make sure the pistons are totaly clean grese all pins and moving parts (not the pistons lol) finaly get some proper brake fluid into it
good luck

I might be tempted to skip the water rinse!