norkona

I have a problem re-installing the right arm of my front break (Suntour XC) on my newly acquired vintage Kona Cinder Cone after stripping and cleaning the whole bike.

No problem for the left arm. Its spring engages into a hole on the fork boss. It works perfectly when the bolt is tightened with a washer on.

The right arm has its own spring block (for spring tension adjustment I suppose) that I believe should come in direct contact with the boss on the fork (not 100% sure). When I tighten the bolt in, the whole assembly gets locked, i.e. the arm can't move. I tried different sizes of washers on the bolt but can't get the spring block to stay in position (supposedly pressed against the fork boss by the bolt) and the spring loaded arm to move freely. What am I missing? I realize I may have lost a part (washer, bushing, or something else). See pics for what I have and the order I am assembling them. I can't find an exploded view of this model or the manufacturer installation instructions on line. Any suggestion is welcome.

Chicago Al 

Hi, Norkona:

Funny you should post this (not funny you have a problem though) yesterday as I am about to reinstall a set of XC Ltd brakes on an early 90s Paramount PDG MTB. I took it apart a week ago and hope to put it back together tomorrow, including the brakes. I will likely be looking for diagrams etc too! I am pretty sure I did not lose anything.

The parts you you have look right to me. But I think if you look closely you will see that on two of the springs, the 'ends' are cut a little shorter, and I think this is because they are intended to go into that chrome bushing with the wrench flats on it, and NOT into the holes on the boss. I will be back on this tomorrow and will let you know what I come up with. I have pics of the brakes installed, before I removed them, which I can post as well.

Update: here is an earlier thread in this forum, which notes that in fact the spring on one side only goes into that bushing rather than the boss on the canti post.

https://www.bikeforums.net/bicycle-me...e-oddness.html

And if you read down in this Sheldon Brown article (go to Dia Compe) it says the same thing, but suggests there should be a brass sleeve which goes over the boss.

Adjusting Traditional Center Pull Cantilever Bicycle Brakes

I was just looking at the brakes, put a pair of them on the bike's fork, and ran into the same problem you did. But perhaps I had the wrong 'side,' ie it didn't have that sleeve. But that's a job for tomorrow. Don't worry, we'll figure this out.

Slash5

The right arm looks like it has an integral inner sleeve and bushing. When you tighten the bolt the inner sleeve is captured and the arm should pivot on the bushing. The bushing may be seized on the inner sleeve.

Chicago Al 

This shows the install and adjustment of very similar brakes (in fact the Suntour ones were certainly made by Dia-Compe), but doesn't address the binding problem you and I are having. I am going to be fiddling with it, suspect it's just a matter of getting the right arm, spring, barrel together.

Chicago Al 

Success! Norkona, hope you are following this thread or have solved the problem on your own.

It's just as Slash5 said, the arms that are intended to be adjustable (the ones with the 'hook' for the straddle) have an inner sleeve, and that can easily get stuck and/or seized. I'm surprised this happened on mine as they were working fine on the bike, however I had not pulled them apart for cleaning and they sat for a week as I tended to other stuff on the bike. One came out easily, I gave it a quick run with a dremel and wire brush wheel, some Tri-flo, and of course cleaned out the inside of the bushing. Mounted it up on the fork and it worked like a charm. I do think that you want to put the spring with a shorter 'tab' into the adjuster.

The second one resisted coming out a little, and I had to put the arm in a vise and tap the sleeve with a nail set and hammer--gently. As you can see it's pretty cruddy but I'm sure it'll be fine with some light abrasion, cleaning, and lube.



Now...will the XC Ltd shifters and RD work with the 7 sp Shimano cassette the bike has, ie will it index? It did pretty well on the 8 sp cassette but of course wouldn't do all the cogs, so I went to 7sp. (This bike came to me with all the XC gear but the wheelset.) It'll certainly work in friction mode but it would be cool if it all worked together.

FBinNY 

The total stack of the parts is the same, right and left. So you're missing something if the front end is extending past the post and binding when you tighten.

Possibly the back plate of the boss is a bit bent pushing the spring cam out a bit, or you have springs reversed or upside down so a leg is going past the cam or brake and binding.

One thing you might try is mounting the right brake on the left post to see if the issue is the brake or post.