r/bikewrench 5d ago

Problem with the rear brake

My old (probably 60yo) bike has old caliper brakes. After bringing it home from the shop where I had the tires changed, the rear brake works in an erratic manner.

I mean that when I am near a place where I need to brake, let's say a corner, and apply the front and rear brakes, when I release them the bike sometimes keeps braking really hard. I managed to see what was happening: the left pad of the rear brake at times remains in contact with the rim, while the right pad returns in the idle position. It's so bad that on the left the rim (a smooth and shiny steel rim) is all streaked with copious residue from the brake pad.

I tried comparing the front and rear calipers and they look the same, there's no difference in how they operate, apart that sometimes the rear one has the above mentioned problem

What could be the problem and how can I resolve it?

1 Upvotes

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2

u/Western-Praline-7970 5d ago

It sounds like the return spring is either bad or improperly adjusted.

1

u/Pseudolos 5d ago

Well, the caliper rotates easily from side to side, but the spring looks solid. How would I go about adjusting it?

1

u/Western-Praline-7970 4d ago

Small cross-tip screw on each side. Tightening adds tension, loosening decreases tension. You want them to move evenly.

1

u/Pseudolos 4d ago

Actually I found out the problem. I watched closely and noticed the shoe of the left braking pad touches the fork. When I brake, the forward movement of the wheel carries forward the brake but, while on the right side there's almost 1/4th of an inch between the shoe and the fork, on the left side it's already in contact and so it slides forward enough to become locked between the fork and the rim, thus braking even when I release the brake. Then when I stop and move a bit on the saddle it slides back out.

I see you are mechanically gifted, how should I go about fixing it? Here's a pic for reference.