Bicycle Mechanics - Locked Brakes

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Niceaction
05-25-08, 05:37 PM
Hi there,

I was wondering if someone could help with a problem I am having with my mountain bike. I purchased it about 5 months ago, but haven't been able to ride it for the last 3 months due to an injury. In this time the bike has been in the shed and hasn't moved.

I tried to get the bike out today but have found that the front and rear wheels are both locked as if the brakes are on full.

The bike has hydraulic disk brakes and i've not had these on a bike before so am not very experienced wit them.

Does anyone know if this is a common problem with these types of brakes? Any sugestions as to how I can get the wheels moving again?

Thanks.

Retro Grouch
05-25-08, 05:56 PM
I don't know where you live but 5 months ago it was winter and cold out. I suspect that the warming weather has expanded your brake fluid and hydro-locked your brakes. If that's the case, bleeding the brakes will fix it.
Niceaction
05-25-08, 06:42 PM
That sounds plausable. Thanks, i'll give it a go.

Joshua A.C. New
05-27-08, 02:09 AM
That doesn't happen. Hydraulic fluid is chosen because it doesn't change density the way, say, air does in a pneumatic system.

There's a chapter in here (http://www.amazon.com/Bicycling-Complete-Bicycle-Maintenance-Repair/dp/B000RIIXBI/ref=pd_sim_b_img_1) about adjusting and repairing hydraulic brakes. I suggest reading up first, or taking it to your LBS.
dabac
05-27-08, 04:04 AM
..t haven't been able to ride it for the last 3 months ..have found that the front and rear wheels are both locked as if the brakes are on full...The bike has hydraulic disk brakes

I don't know if bike brake rotors are always stainless or not. If they aren't there's a possibility that rust between rotor and pads are keeping the wheels immovable. Fairly common thing over here for vehicles that only gets used seasonally. Best option in that case would be to pull the pads, clean the rotor, install new pads, hope for not significantly scored rotor and get back to riding. Crude option is to force the wheels to move and hope that normal wear will clean things up. Put bike upside down and start pulling/yanking/wiggling wheels back & forth. Brakes would be very grabby during braking initially after having broken free.