Adjusting Lee Chi Sidepull brakes
 

I have a men's bike that says Venture on it. I think it is made by Raleigh and I am having trouble adjusting the front brakes. They say Lee Chi on them ( side pull ). At first they wouldn't budge so I took them off and cleaned them all up and oiled them where oil was needed, then made sure they were put back on the bike the EXACT way they came off but when I apply the brake only one side pulls in. Yet I have checked that they are centered and there is no play in them and when I squeeze them by hand they both go in and out smoothly. I must have missed something but not sure what. Can anyone give me some advise on how to fix this problem. I have even tried to center them with an offset wrench and a wrench on the back nut. This brake assembly has two nuts at the front of the brake and the slot for an offset wrench.

Thanks... Greg

I'm a bit confused about the post. You say only one side goes in, do you mean only one side releases.

The way brakes work, is one when side touches the rim first, it stops moving and the cable tension forces the other in. It doesn't matter that one side touches first, it cannot exert any pressure until the other comes in and they squeeze together.

The usual problem is that one side doesn't release and even adjusting the balancing screws doesn't solve the problem. If that's your problem come back and I'll suggest ways to deal with it.

Hard to follow descriptions

also, those brakes are likely crap and perfection is probably asking too much of them.

I'm guessing that the spring is assyetrically balanced, hence one side of the brake prefers to move more than the other. Combined with a lack of cable tension; this could produce the symptoms you describe of: only one side moving.

Try this:
unbolt the cable from the brakes
hold the brake closed against the rim (a 3rd hand helps here)
pull the cable tight
rebolt the cable onto the brakes

recenter the brake so neither side drags the rim when not in use
likely wont be able to make both sides contact at the same time; so just focus on neither one dragging

Cheap side pull brakes can have a lot of slop between the spring and the center bolt "block' that the spring is held in. The slot the spring sits in is often a bit too large and the spring can rock/shift within it. Why is this a concern in your case? Because the rotational arrangement of the spring is what controls a lot of the pads releasing off the rim equally. And if the spring rocks/moves within the slot the pads will seem to be centered one time they release then the next time the spring rock allows the pads to "move" to one side (or the other).

Also cable casings can act as a spring, pulling/pushing one side of the caliper more then the other side. Andy.

I disconnected the brake cable and made sure that it was free moving and wasn't sticking. Then centered it and did what Xenologer said and put it back together that way. But when I squeeze the brake lever only one side goes against the rim and the other side stays put, Strange...

Thanks...Greg

This defies logic, unless the cable is so slack that you run out of lever travel with one side touching and before the other is forced to move.

Newton's 3rd law of motion dictates that the force then housing exerts on one arm is equal and opposite to that which the inner wire applies to the other. Likewise no arm can exert any force on the rim until the other comes into contact.

As I think about your problm, I suspect that you simply have the brake cable adjusted so long that you run out of trave,.

Try this, disregard the cable, and squeeze the upper and lower arms together (where the cable and housing are) and see what happens. If both move in your hand, they will when the cable is a attached.

Ohterwise (and don't get offended) two other possibilities exist.

1- you're trying to string a cable without housing
2- the housing coop is cut so short that it cannot move down pushing the brake arm before it.

Otherwise, a photo may be necessary for us to help.

In many cases problems can be solved by observation. If you look at how the brake is actuated you will see that when you pull on the lever the cable moves up, pulling one arm in. But both ends of the housing that the cable goes through are stopped, at one end by the brake lever body and at the other end by a ferrule on the other brake arm. Because that other arm also is allowed to pivot the housing will normally push it down, pulling in the other brake arm.

If the housing is too short the cable will pull up on one arm but the housing will not be able to push down on the other. You need a gentle curve on the housing as it goes down to the brake, enough so that there is still some curve left when the brake is against the rim on both sides..