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need help centering side-pulls(4 posts)

need help centering side-pullsmoschika
Aug 5, 2003 2:55 PM
i can't seem to keep centered my older shimano 600 side-pulls. when i squeeze the brakes, one side of the side-pull opens out fine but the other side usually stays up against the rim.

is there a way for them to stay centered? when i tighten them up, then the calipers don't move.
How are you trying to center them?Straightblock
Aug 5, 2003 3:40 PM
Some models of older sidepulls have flats on the centerbolt for a cone wrench-old Campy Record used 13mm, and I had some Gran Compes or some other Japanese brake that used a 10mm. I have an early 600 set on my beater that has a 5mm allen head fitting on the end of the centerbolt. If this is what you have, there may be a rubber plug in the end that you need to remove to access the allen head.

Assuming your brakes are similar to one of these, loosen the nut on the back of the brake and use the appropriate wrench to turn the centerbolt and center the brake. Be sure to squeeze the lever a few times to release any tension that may be left. Hold the centerbolt with the wrench while you tighten the nut and you should be good to go. You might want to put a drop of lube where the springs contact the arms and where the arms pivot on the centerbolt to be sure they aren't sticking.

If your centerbolts don't have any wrenching point, the last resort is to tap down on the spring with a hammer and flat punch on the side you want to move closer to the rim.
re: need help centering side-pullsxcandrew
Aug 8, 2003 12:09 AM
"when i tighten them up, then the calipers don't move"

It sounds like the locknut is loose on the centerbolt. If it has an adjusting nut and locknut in front, tighten the adjusting nut to take out any play while allowing free movement of the arms and lock the locknut down on it. You'll need a thin brake wrench.

If the brake is the model from the mid-80's or thereabouts, the front of the brake has just one cone shaped hex nut that you can center the brakes with. In this case, the nut that carries the spring on the backside is the adjusting nut. You need to remove the brakes from the frame. Use a thin brake wrench on the flats of the spring carrying nut to take out the play (while allowing good rotation of arms) holding the nut in front with an allen wrench. Then tighten the back locknut and the spring carrying nut together. Put it back on your bike and center using the front nut, and squeeze the levers a couple of times to make sure it's centered.

If the adjustment is fine, clean the springs and the arms where they contact each other. Friction/dirt here is the main reason why sidepulls come uncentered. If there are plastic sleeves on the spring at the contact point, that's a good thing. It reduces the sliding friction between the two parts. Older brakes without the plastic sleeves uncenter easier. Make sure you have one one each side, not just on one side, because that would cause the brakes to go off center too.
Centering procedureCalvin
Aug 12, 2003 2:19 PM
It is likely these are the "safety pivot" type. If the pivot adjustment is not correct, they will never stay centered. See http://www.parktool.com/repair_help/sidepull.shtml
After adjusting the pivot, use a wrench in the front bolt and on the mounting nut. Move both wrenches together to align pads.