Bicycle Mechanics - Canti problem (stiff arms)

Dear All,
my wifes bike is sufering from poor braking at the rear. When you pull the brake lever, the left hand arm pivots towards the rim as it should, and all is well. The right hand arm (the one with the adjustment screw) just stays there, and is too stiff to move with the cable. I took it off and greased it, but it made no difference once I tightened it fully down. How can I improve matters?

The brakes are Shimano Altus, and it uses a Shimano straddle cable.


Thanks in advance!

check to make sure the "Y" cable pulls from the centre, not from either side.

Is there a spring problem that's jamming the brake arm?

I am not sure, but when I installed a pair of those brakes recently one a bicycle I remember torqueing the bolt fastening the canti arm to the frame to the point that it had immobalized the arm. I had to back the bolt off,file the arm a hair, relocktite etc, to make it work.

maybe a bad batch of brakes,
good luck.
jk

You need to adjust spring tension, and the way you do that depends upon the particular brakes that you have. You need to post a picture of your brakes.

Those cants are notorious for the plastic spring cover busting. Check the plastic cover for a crack...if this is the case you will never get decent tension out of the spring. A new pair should run about $6-8.

Here are some unconvincing pictures. There are no obvious cracks in the plastic, and I greased it last night. It looked like it might be better if I did not tighten it as much, but it did not improve matters significantly.
I'm about to take the bike to my friendly performance armed with some avid fr-5 levers and suntour xc pro canti's and charge them to make the braking work with either vs or the cantis.

I think the problem may actually be that the straddle wire is too long, and that it is therefore not properly centred.

Have to admit, I've been looking forward to seeing the suntours in action. We need Self Energising power, now!