Hydraulic brake problem

[cyclingfan]

I have a KHS alite 2000 bike with more or less only 800km on the clock. The problem is the front wheel and brake's. I have had it for repairs to 3 cycle shop already and every time they tell me the problem is now solved but I still have the problem. This is the problem. "it starts off fine but the longer you ride the tighter/slower the wheel gets the harder I have to pedal. It feels like riding uphill the hole time". Anybody knows what the problem can be? The one mechanic said that it is really very strange.

[Stretch]

I have a KHS alite 2000 bike with more or less only 800km on the clock. The problem is the front wheel and brake's. I have had it for repairs to 3 cycle shop already and every time they tell me the problem is now solved but I still have the problem. This is the problem. "it starts off fine but the longer you ride the tighter/slower the wheel gets the harder I have to pedal. It feels like riding uphill the hole time". Anybody knows what the problem can be? The one mechanic said that it is really very strange.

 

you sure you just not getting tired

[divernick]

Try a different wheel and see if that solves the issue.

[cyclingfan]

Well the guy who tried to fix it rode the bike and said it is very strange. I knew that this would be the response but I really would like to know if anyone knows what could be wrong?

[Mojoman]

Pistons not retracting back into the caliper?

[Mojoman]

Wheel bearings tighten up on themselves?

[divernick]

Well my curiosity is definitely piqued.

[cyclingfan]

I also thought that it might be the bearings. Was thinking of taking it to singeltrack to see if they can solve the problem but it is about 80km from where I live I don't want to name the shops which have already tried to fix it.

[Pants Boy]

I've had similar on an old Jeep Willys - turned out to be the master cylinder return spring being fubar. It caused the system to build pressure, thus binding the brakes. Not sure if that's your issue, but have you been able to identify WHERE the problem is? IE is it the wheel, or the brakes?

[Jay_B]

Try working out what is causing the problem, the wheel (i.e bearings) or the break and take it from there....

[TheV]

You should go for a night ride, and film it using an infra-red camera, maybe there is more to this than we might imagine... evil spirits might be at play here...

[Pants Boy]

Yah, forgot about that - have you checked for a tokolosh yet?

[DR ◣◢]

What happens with the lever when this happens. Does it get harder to pull?

 

My guess would be the heat from the disc is causing the piston to expand and bind.

 

What brakes are these?

[rvdm1]

My dad has the same problem on his Trek Fuel ex5, not certain what brand and model brakes it is though. I haven't personally seen or felt what happens but it sounds as if the brakes don't open after releasing the brake lever and still creates friction on the discs.

[droo]

When the brakes cool down, does the problem go away? If yes, then it's probably just air in the system and a bleed will sort it out.

 

If not, then it may be sticky slave piston seals or a faulty master return spring as mentioned earlier.

 

Wheel bearings would be easy to confirm - when the problem occurs just take the wheel out and see if the axle turns smoothly. If it's a battle to get the wheel out then it's your brakes.

[Dirtbreath]

Had a similar problem once. Turned out the diaphragm was put in wrong. Affected the flow of mineral oil.