BeeRich

Hi folks.

My front brakes need some attention. Both sides just greased, then tightened. They both move. Driver side is dead stuff and sits on the rim. Passenger side is allowed to separate from the rim. Not sure why driver side is so tight.

Anybody know what I need to do? Otherwise great brakes.

Watch here:

Bill Kapaun

Did you try adjusting the screw?
Spring hooked into the hole?
What's it do if you disconnect the straddle cable? Just flop? If so, it would be a spring issue.

cxwrench

It's not 'driver side' and 'passenger side'...it's drive side and non drive side. Please. As for your brakes, either one side is dirty/corroded, the spring needs to be adjusted or the spring leg isn't in the same hole on both sides.
ETA: It looks like your rim is totally worn out and the pad may be getting caught under the lip of worn section.

andrewclaus

You don't show the cable hanger. Some of them mount to the headset and can rotate. It looks like yours might be rotated too far to the drive side. Then you'll need to move the pivot point of the link wire. Slide it down closer to the cable pinch bolt on the non-drive side caliper.

See Sheldon Brown's article on cantilever brakes.

Andrew R Stewart 

Someone should take the RH side (any question as to which side that is???) off the post and see why the spring is not providing enough tension to rotate the pad away from the rim. It's possible that the pad has worn enough and unevenly so that it now has a lip along the bottom edge that's catching on the rim and keeping the pad there. Given the rather unevenly positioned pads and that the RH side's pad is not tangential to the rim (the rear end of that pad is close or is touching the tire) I would not be surprised if the spring was installed into the wrong tab holes.

Besides taking that side off the post to look at the spring ends positions and besides the poor pad alignment WRT the rim I would also position the pads further out on their shafts so the arms angle outwards a bit more. This will lower the straddle cable clip (yoke) and increase the leverage of the set up. As andrewclaus suggested check out the Sheldon Brown instructions. Andy

smd4

Looks to me like those brakes need to be completely readjusted from the ground up. So much looks wrong here.

BeeRich

I did try the screw, and it did nothing. I'm thinking it needs a new screw. I will replace the whole set.

Cheers

BeeRich

Wow I apologize. Did I offend you? The rim is not worn out, nor is the pad. It sits properly.

Crankycrank

As Andrew mentioned, are you sure the spring ends were properly inserted into the holes of the brake mount and brake arm when you installed it after re-greasing?

BCRider

It's possible that the retraction spring on the left side is broken internally. Otherwise I'm also thinking that the pin for the retraction spring is not in the proper matching hole on both sides. The other things like how the hanger is positioned also comes into the issue. But that's the finer detail stuff. You've got a major issue of the right (drive) side arm having strong retraction force and the left (non drive) side having very little or no retraction force at all. So either badly mismatched retraction pin hole selection or the left side arm has a broken spring. Especially when the adjuster screw has zero effect. That alone makes me think it's a broken spring on the left side.

BeeRich

That's what I'm thinking. Any chance you know where I can pick up a set of springs? They're all originals from 1992, so might as well replace the whole set.

Cheers

BeeRich

Wasn't a complete removal. Just a loosening to get the grease in there. I should be taking it apart as a full service. I'm going to look for new springs as well.

BeeRich

OK, but I never said the screw was stripped. Nothing is stripped. The cantilever moves and isn't tight. It's just forcing against the rim for some reason. I have to have a better look. The reason I'm asking in here is because it seems to assemble just fine. The mounting screw seats pretty solid against its seat, and it still pivots fine. It keeps the clamping from happening.

Leisesturm

We know you never said the screw was stripped. You said you tightened it and nothing happened. The other poster said, basically, that that is impossible unless the screw is stripped. They are not wrong. To be fair to you, however, that screw is very tiny and has a tiny range of adjustment. It's easy to miss the fact that something is in fact happening, just not enough of that something. Sadly, you need that kind of fiddly, one half turn is the difference between a pad dragging and not dragging, frustration, to make these brakes work optimally.

It is probably not the tiny adjustment screws. Set them halfway through their full adjustment and start all over. The posters saying the ends of the springs that fit in the small holes on the brake bosses are mismatched are probably right. There are usually three small holes vertically placed on a plate next to the boss. The middle hole is a safe one to start with. Make sure the ends of the spring on each side of the front brake is in the middle hole as you slide the caliper arm onto the boss. It is easy to get wrong.

There is no shame at all in taking this bike to a bicycle co-op where you are encouraged to watch while the tech works on your bike. You haven't offended anyone that I can see, but I can tell that you don't have the experience necessary to get your bike back to the factory defaults. Buying new brakes will only kick the can down the road because they WILL get out of adjustment as well. It's the way it is. Since there are bike stores and bike co-ops (that are practically free) you absolutely do not have to become a bike mechanic yourself. But it really, really, helps if when you bring an issue to a forum of bike wrenches if you can use the proper names for things, and follow the conventions of troubleshooting procedures. These days the easiest way to get up to speed with all of that is YouTube videos on the part of the bike you have an issue with.

BeeRich

Two screws here. There is the mounting bolt/screw, and there is a tiny limit type screw. The latter I tried and it did nothing, up and down. Taking the bike into a shop here in Toronto means I don't have my bike for a month. I've been working on my bike for 45 years, and I'm fixing a bunch of other things right now. I just wanted some suggestions as to what it could be. It's so out of whack that I thought it would be immediately assumed it was something that's common. I haven't taken it apart yet which I intend to get accomplished soon.

400E

If you really want to understand how your brakes work, and how to troubleshoot them, I'd suggest getting one of Leonard Zinn's bicycle maintenance books. He goes into detail about different types of rim brakes, has exploded diagrams, and helpful repair tips.

smd4

There aren't two "screws." As you noted, there is a mounting bolt.

I know pictures can be deceiving, but from what I can see, your brakes need a bit of work. The shoes don't appear to be properly aligned, *to me.* Not that that is the issue here--but it could be.

Cantilever brakes are pretty simple. If you've been working on your bike for 45 years, the problem should be very apparent to you, since you are not looking at photos/videos of the problem from behind a computer monitor. I agree with the others. Either you didn't position the spring properly, or it's broken, or the arm is grabbing on the shaft for lack of lubrication, or maybe you even forgot to install the spring. Unlike the rest of us, you have the ability to disassemble the brake and see what the problem is.

Rick

I have had this problem before. I removed all crosion from both cantilever studs with drywall sandpaper. lubed the studs. Then I pulled out the wheel and twisted each brake arm to weaken or strengthen the springs so they are more equal in tension. This allowed the adjusters to fine tune.

BCRider

That's a perfect time for the tang on the spring to jump from one hole to the next and not notice. Cheaper bikes only have one hole but most medium and better have three holes to permit setting the overall retraction force. It's HIGHLY important that both sides use the same hole.

You don't even need to remove the arm to see which hole the spring tang is in. You should be able to look in from behind the legs and see the holes in the canti stud's base plate and see the tang sticking through. If they are not in matching holes then fix that to start.

If they are in matching holes or there's only the one hole and the tang is showing in both then it's highly likely that the left arm's spring is broken. You can check for this too. Unhook the straddle from both of the arms and remove the front wheel. You don't NEED to unhook the cable from the cable clamp on the left arm but if you are at all in doubt about it then I'd do so. It's only about 30 seconds to remove and re-set later.

With both arms totally free free they should both retract away with somewhat similar pressure. If the left side arm has a broken spring then the spring action will be either not there at all or it'll be very odd feeling when the ends touch to give you some spring but it's not the same or even a proper sort of feel.

For that age of brakes you simply won't find parts other than in the "Ye Olden Box of Parts" kept under the work bench. And since it sounds like you don't have that sort of box you'll need to go around to the local bike shops.

I'd say that if you like the bike enough that this might also be the time to switch over to a V brake setup. It'll cost more since you need to buy the brakes AND proper matching levers though. But if you enjoy the bike enough it would be a nice upgrade at the same time you fix the broken brake arm issue.

RGMN

May I suggest looking at this: Cantilever Smooth Post Brake Service | Park Tool

jo_lacs

Hi. I hope this helps. Those particular era of Shimano cantilever brakes had 2 spring tension settings namely, "SLR" and "normal" settings. I think SLR stood for Shimano Linear Response? or something. Anyway, these settings are visible from behind the arms on the plastic caps that cover the tension springs. There should be 2 arrowheads on the plastic cap, one for "SLR" and one for "normal". I'm guessing that you might have one brake arm set to "SLR" and the opposite arm may be set to "normal". The settings should match meaning they should both be set to either "normal" or "SLR". You change the spring tension by inserting the hidden end of the tension spring into the appropriate hole so that when you put the plastic cap back on, it either points to SLR or normal.

BeeRich

Yes, have seen that. Probably the best instructions I'll find. Cheers

BeeRich

So it was the spring. It sat in the wrong hole. Corrected, with an alignment of the pads (service) and works like a charm.

Cheers

Rogerogeroge

Those brakes first need to be set up correctly. Pic 1 shows the pad hitting low on the rim, and the lower edge of the pad may not even be contacting the rim. Pic 2 shows the pad hitting high on the rim, almost into the sidewall of the tire. Look at pic 3. One arm is more ‘vertical’ than the other. The arms should be angled the same and should be symmetrical. If you look at the slots above the brake pad posts, one is showing 1-2 mm gap, and the other has about twice the gap. Again, needs to be symmetrical. You can mess around with the spring tensions all you want, but it’s in vain if the brakes aren’t set up correctly.

BeeRich

Yes, it got adjusted. I'm running tires that clip the top of the pads, but it's been serviced and is all fixed now.