okane

I have this World Sport (no laughter please...I like em!) a while back and in getting it ready for the road I noticed that the hole in the break bridge for the caliper is ovalized just enough do that the caliper moves up & down/back & forth (take your pick) during braking, thus no rear brakes to speak of.

It is one of the full cro-moly frames and I like the color, but it's not worth the expense of having a pro install a new brake bridge.

Any suggestions for a fix, or as the title indicates, is it junk?

blamester

Tighten the nut up properly. See does it move.

fietsbob

some one over tightened the mounting nut thinking it would tighten the brakes , themselves?

okane

I tightened it the point I felt I was getting close to torque limit....worked ok on the stand but when riding it moves.

rhenning

You take the up and down looseness out by using the 2 nuts on the front of the brake. Loosen then from each other. Tighten the inside one on the brake to take out the slop and wiggles but let it still move freely. Tighten the outside nut so the adjustment doesn't move. Ride the bike. Roger

fietsbob

if you are willing to fabricate DIY, get some steel tubing with a 6mm ID, and fit it through a slightly enlarged hole
you make through the seat stay brace..

Added tube will resist compression because you are squeezing its ends.. not just across the hollow tube..

Physics of braking makes rear brakes not needing super strength because your weight is more on the front ..

https://en.wikipedia.org/wiki/Newton%27s_laws_of_motion



..

wernst

Yours is a 1987 or 1988 World Sport, and they are great cruising bikes. They were also index-ready. If you haven't already, replace the friction stem shifters with 6-speed Shimano indexed shifters, and the freewheel and Light Action derailleur are compatible and ready to click! These ones are perfect. Previous advice about fixing the brakes are spot-on.

CliffordK

If you have someone that can do a little brazing, then you could braze on some saddle washers, similar to this.

https://www.pegasusautoracing.com/pr...uct=3077%2D002



If one had the parts that fit well, then it would be an easy brazing and reaming job.

You could, of course, also ream the back side for a recessed nut too.

Gresp15C

From the pic on the right, it almost looks like the piece that the spring fits into, is cracked.

I have two Schwinn frames of similar vintage, and I love them. They are a great raw material for building up nice classic bikes. One of mine had those old Dia-Compe brakes, and the best thing I ever did for a bike was to replace those with modern Tektro dual pivot brakes. The old brakes were just so mushy. I don't know if was from years of use, or if they were crap brakes all along.

Tektro still makes ones with the non-recessed nuts. You have to research the part numbers a bit to make sure you get the correct reach for your bike.

One thing to do is to tighten the nut with one hand while you force it upward with the other, so it has no further to go when braking force is applied.

cny-bikeman

Unless it's really bad I don't see what would cause it to move much, as you only apply the brakes when moving forward. Just pivot it down and tighten well. However, if you do need to fix it here's an idea:
See if you can get a sleeve the right ID to just fit over the center bolt where it goes through the bridge. Cut to length just longer than the brake bridge. Drill out the bridge and fit washers to the same OD as the sleeve, then assemble.

Kontact 

I agree. The brake looks cracked. Is it?

okane

First, thanks for all the info.

I have spinal stenosis and the first thing I did to the bike was install a riser bar, new brake levers, and a Shimano trigger shifter and compatible drs. Works well for me as to pain, but upright is a terrible way to ride, especially on windy days.

I did check the caliper and it looks like it may be cracked in the photo, but upon close inspection last night it isn't.

Easiest suggested fix is to hold caliper in down position and tighten..makes sense and I will try this first.

Brazing the saddle washers in place also seems like an easy fix and I know someone who may be able to do this. I'm guessing that the caliper should be in place in the correct position while brazing**********

Using a shim sounds like a good idea, could you suggest where I would get something in the size needed?

Again, thanks for all the replies. Maybe I can save this one.

okane

Could you elaborate on this a bit...I'm not sure I understand. Thanks.

fietsbob

1) fill the drilled hole the bolt will fit through, (| |) with a liner tube of steel, glue in with epoxy, no burned paint..

2) 'a body in motion tends to stay in motion until affected by an opposing force'

Gresp15C

Yup, both of my Schwinn frames now have "north road" style bars. I don't have a diagnosed condition, but I greatly prefer the comfort of the upright posture, and living with the aerodynamic penalty is worth it for me. The ability to fit parts from a wide range of years is one thing I like about the Schwinn frames.

Deleted my lengthy message after seeing what @fietsbob wrote. I was over-complicating things. The existing aluminum saddles can't be brazed by mere mortals. They would have to be a compatible metal such as steel.

But I like the idea of a liner tube and epoxy. You can always bore out the tube to a larger diameter if needed. My favorite heavy duty epoxy is JB-Weld, which you can get at the hardware store. The surfaces have to be clean and free of oil. It takes at least overnight to cure, so be patient.

fietsbob

Another old thing; an L shaped piece bolted under the brake shoes .. got adjusted so as to hit the frame, when the rear brake flexed a little,

when putting on their rear brake..

CliffordK

You don't really want to braze the brake in place. However, the brake center pivot bolt simply needs to be centered and perpendicular to the seatstays.

Ideally one could just use a bolt to hold the washers in place while brazing. The existing holes would help align it. However, I'm not sure how to prevent the brass from sticking to one's bolt. Perhaps one could tack it, then clamp and finish brazing.

It might take a little more research if going with that method.

cranky old road 

Perhaps I am being silly, but it seems that if the OP rotates the brake as fully down as it will go before tightening the nut and sets the brake shoes with the proper bevel the braking should be fine. One does not, after all, need to brake in reverse, so the rim's pull on the brake should be unidirectional.

fietsbob

If brazing, and burning paint, to get bare steel the face pieces can be steel flat washers..

the brass filler melt will go between the round tube and the flat washers..

by the way brass has a harder time bonding with stainless steel , ..





...

MisterK

Any chance you could drill the holes a slight bit bigger and source out a new bolt for it?

Kontact 

The brake doesn't have a bolt.



It sounds like the OP needs to just tighten the mounting bolt on his caliper properly, rather than drill, epoxy, sleeve, braze or anything else. Like wheels, the brakes are not held in place by the size of the hole but by the clamping force of the hardware. An oversized frame hole is no different than a horizontal dropout.

cny-bikeman

That has essentially been suggested, but unknown if the OP has tried that.

cranky old road 

Needs to make certain that the rear of the shoes are slightly further away from the rim than the front of the shoes to prevent chatter.

capnjonny 

If you haven't yet , check out:

https://www.parktool.com/blog/repair...icle-section-7

the tool, Park OBW-4 , is the one for the job. It's worth picking up.

The whole article is required reading.

If your braking is sub par a set of Kool stop Salmon pads will help.

Kontact 

The Park article is written as if most sidepulls weren't centered by tapping the spring arms with a punch. I guess Park doesn't sell punches.