How do I even up cantilever brakes?

[swee'pea99]

Front & back, same deal - only one side moves. T'other stays rubbing on the rim. I can easily move it back by hand, but the springs on each side don't seem to have equal 'pull'. I know how to adjust caliper springs - you just unclip the buggers and bend 'em a bit more. But I can't actually see the springs on these...they seem to be internal. There's a wee screw on each arm - is this some kind of adjuster? Thanks if you can help.

 

[mickle]

Screw it in to increase spring tension.

 

[swee'pea99]

Thanks Mickle. Partial success. On the front one, I needed to decrease the spring tension on the adjustable side, which I managed to achieve by loosening off the screw - so that one's fine now. On the rear tho', I do need to increase the tension on the adjustable side, but the screw's already all the way in, so I'm a bit stumped. Any ideas?

 

[Amanda P]

In my experience, this seems to be a perennial problem with cantis, especially when only one side has an adjuster screw.

The cure (I'm afraid) may be to remove the calipers and springs from the frame, clean everything up (including the bosses on the frame, which usually rust, so a little fine emery cloth or wire wool may be needed), apply a little grease, rebuild and then adjust the balance with the adjuster screws.

Be careful not to lose any parts, remember what order they were in - there may be washers that are important. Remember also which of the holes in the boss the spring was hooked into.

My 80s Galaxy needs this treatment at least once a year. Mrs Uncle Phil's Orbit less often, but sometimes rust and gunk build up to the point where friction overcomes the spring tension in one or both sides and a strip-clean-rebuild is the only way to sort it out.

 

[tyred]

I had this problem and worked some WD40 into it. Seems to be okay so far but a strip and clean would probably be a better solution.

 

[palinurus]

Sometimes if the cable hangers are a bit off-centred this can happen.

 

[swee'pea99]

Thanks all. I'll try working some lube into it & see if that helps. Not really keen to do the full monte unless it proves absolutely necessary.

 

[Night Train]

I have the same problem on my old hack. The side that needs the screw winding in is already all the way in and the other side is all the way out. Have stripped, cleaned and rebuilt and I reckon a) the springs are knackered, the adjusters are knackered, c) I need to replace the whole brake mechanism.

Is there anything better to replace the whole thing with or just like with like?

 

[gwhite]

I have the same problem on my old hack. The side that needs the screw winding in is already all the way in and the other side is all the way out. Have stripped, cleaned and rebuilt and I reckon a) the springs are knackered, the adjusters are knackered, c) I need to replace the whole brake mechanism.

Is there anything better to replace the whole thing with or just like with like?

It's worth doing the whole job. Dismantle and clean and grease the bosses. Remove the springs and either put these in a vice and bend them so as to increase the tension, or buy new ones and replace. Replace the arms and put locktite on the fixing screws ensuring that you do not overtighten. Put both adjusting screws to mid position and, leaving out the brake blocks, pull the cable through the pinch bolt until the arms are vertical. adjust screws until both arms are equidistant to the rim. Fit blocks while arms are in vertical position and bring these up against the rim with an elastic band on the trailing edge to ensure toeing in. That's it really.

 

[BADGER.BRAD]

If you do take the brakes off you will notice ( in most cases) that there are three holes in the frame that the spring end fits in. By altering the hole that you put the spring end in you can alter the spring tension I have in the past found that they generally seem to be set up in the middle hole or the hole at the loose end of tension as standard. Worth a try.

 

[Night Train]

It's worth doing the whole job. Dismantle and clean and grease the bosses. Remove the springs and either put these in a vice and bend them so as to increase the tension, or buy new ones and replace. Replace the arms and put locktite on the fixing screws ensuring that you do not overtighten. Put both adjusting screws to mid position and, leaving out the brake blocks, pull the cable through the pinch bolt until the arms are vertical. adjust screws until both arms are equidistant to the rim. Fit blocks while arms are in vertical position and bring these up against the rim with an elastic band on the trailing edge to ensure toeing in. That's it really.

Did all that the first time around though without the locktite or new parts so I figured the springs were knackered.

If you do take the brakes off you will notice ( in most cases) that there are three holes in the frame that the spring end fits in. By altering the hole that you put the spring end in you can alter the spring tension I have in the past found that they generally seem to be set up in the middle hole or the hole at the loose end of tension as standard. Worth a try.

Yep, I did try different holes.



Took them apart and had a closer look now. The adjuster on one side isn't catching the spring end. It pushes on the spring a bit and then the spring flips off it. The screw feels loose in its threaded hole. I think it will be easier to just replace all the parts and be sure that the brakes work.

Thanks for the advice.

 

[mountainrider]

Easy if you know how.
1. if the adjuster screw does not do the job you need to lossen it of to a neutral position first.

2. if you remove the hole canty by the 5mm bolt on the front you will find the spring slots into one of the 3 holes on the frame.ideally it will be the same on both sides, middle hole preferably. if not and you think it will rectify it put them in same hole. or ( after cleaning and lubing everything) put it in the hole best suited to balance your problem.
3. replace bolts, then fine tune with the adjuster screw.

if either side does not rotate smoothly it needs cleaned lubed and if necessary sanded down to remove corrosion on the frame mount or it will never work.