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80's Kuwahara MTB Brake Issues

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80's Kuwahara MTB Brake Issues

Old 04-24-20, 09:34 PM
  #1  
SimpleScott
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80's Kuwahara MTB Brake Issues

Hello BikeForums members!

This is my first post here after lurking for years, gleaning as much useful information I could from these archives. I've researched and read as much as I could about these brakes and I now present with an issue at hand on a 1987 Kuwahara Sage MTB. I purchased this frame second-hand with only the front brakes installed. It wasn't loved for a while before becoming by winter beater.

Since I can't upload photos, the album is visible at this imgur link. imgurDOTcom/a/IySXv9S. As you can see in the first photo, brake installation involves sliding the brake over the threaded bolt, and then onto its pivot resting place, then the spring is attached to one mounting hole on the exterior of the boss and finally a nut is threaded to secure the brake. I've italicized things that appear to be extra-ordinary and troublesome to find information on.

I am looking to give the bike a further overhaul as it has everything I need BUT an easy brake conversion.
Has anyone had any experience with this style brake mount?
Is it conducive to newer brake styles?
I have rear brakes right now but they are mighty jerry-rigged and are not long-term solutions.

Any information would be appreciated!
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Old 04-25-20, 12:01 AM
  #2  
Chris Chicago
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I had that spring hole on the outside problem. I know that dia comp cantilever brakes, model 980 work. Here is a thread that discusses others
https://www.bikeforums.net/classic-v...980-930-a.html

Maybe there are some v brakes that would work too, but I've little experience with those.

Good luck
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Old 04-25-20, 12:25 AM
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Originally Posted by SimpleScott
Hello BikeForums members!

This is my first post here after lurking for years, gleaning as much useful information I could from these archives. I've researched and read as much as I could about these brakes and I now present with an issue at hand on a 1987 Kuwahara Sage MTB. I purchased this frame second-hand with only the front brakes installed. It wasn't loved for a while before becoming by winter beater.

Since I can't upload photos, the album is visible at this imgur link. imgurDOTcom/a/IySXv9S. As you can see in the first photo, brake installation involves sliding the brake over the threaded bolt, and then onto its pivot resting place, then the spring is attached to one mounting hole on the exterior of the boss and finally a nut is threaded to secure the brake. I've italicized things that appear to be extra-ordinary and troublesome to find information on.

I am looking to give the bike a further overhaul as it has everything I need BUT an easy brake conversion.
Has anyone had any experience with this style brake mount?
Is it conducive to newer brake styles?
I have rear brakes right now but they are mighty jerry-rigged and are not long-term solutions.

Any information would be appreciated!
Can’t get the imgur link to work.
I’ve seen the outside holes a couple of times. Some brakes don’t actually need the holes as such, the base of the arm(with the return spring adjustment screw) is simply clamped in place with the mounting force of the screw holding the brake arm in.
Otherwise it’s not hugely difficult to make an adapter plate that puts some holes on the inside.
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Old 04-25-20, 04:59 AM
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Originally Posted by dabac
Can’t get the imgur link to work.
I’ve seen the outside holes a couple of times. Some brakes don’t actually need the holes as such, the base of the arm(with the return spring adjustment screw) is simply clamped in place with the mounting force of the *screw* holding the brake arm in.
Otherwise it’s not hugely difficult to make an adapter plate that puts some holes on the inside.
Thanks for the reply Dabac.
The imgur link works for me if I just replace the DOT with a period.
​​​​​I understand there are brakes that have the return spring integrated or held in place with the force of mounting but the main issue I see with this brake mount is that the brake is not held on with a bolt. The brake slides on to the mount and then a nut (either nylock or with a locking washer) and a standard washer are used to secure it to the mount.
I'm not sure if that makes it easier to understand the issue here. If I remember correctly in trying different brakes on it, the mounting post was also a strange size so that even using contemporary brakes with the nut to secure it wouldn't work. I am not 100% on this.
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Old 04-25-20, 06:32 AM
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I don't think the OP is talking about the holes or the U brakes. He appears to be talking about Bolts (this is what I usually see in my limited experience) vs Nuts. His brakes posts are threaded and will receive a nut rather than a bolt.
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Old 04-25-20, 07:48 AM
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https://m.imgur.com/a/IySXv9S is the link to pics.

He could measure the distance of the posts from the drop outs, if it's the same in back as front then it's cantis all over. If not then you got an exotic on back.

Seems like nut vs bolt, though unusual shouldn't be a problem, just get a nut. Do the front brakes fit on back, if so you could look for some on ebay.

Last edited by Chris Chicago; 04-25-20 at 07:53 AM.
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Old 04-25-20, 11:15 AM
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Pic assist





The bosses appear to be the same between front and rear. The stud and outboard location of the spring hole are unusual, but I'll bet someone here will recognize that brake design. First thing I'd do is remove one of the arms from the front, so you can better compare the bosses visually. You could even try mounting the brakes on the rear, just to see if they hit the rim properly.

I wonder if this is it - https://www.ebay.com/itm/303504516991 . Still leaves you one spring short.

Last edited by madpogue; 04-25-20 at 11:28 AM.
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Old 04-25-20, 12:42 PM
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Those particular brakes are excellent in my experience, one of the most compact (and less protruding) yet work extremely well. Even the original pads from 1983 seem to still work perfectly on all of my touring bike purchases that featured these brakes.

I would buy these ASAP, new and perfect:
https://www.ebay.com/itm/Vintage-Dia...53.m1438.l2649

EDIT:
Actually I mis-spoke, those do have the hole positioned on the wrong side of the post it appears.
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Old 04-26-20, 08:44 AM
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Thank you for the responses everyone.
The front brakes do fit on the back. While I don't have a problem with the front ones, the back ones are currently different levers with unmatched springs; not ideal, but functional enough.

I was more curious about potential replacements or modifications. Is the fixed mounting bolt replaceable?
As indicated by a few replies there are brakes available on Ebay as NOS, but do you know of any that are contemporary that will work for this mounting? Perhaps integrated springs? I doubt I'd get V brakes compatible with the outside hole.

I can get measurements today while I disassemble to clean it of its post-winter beating.
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Old 04-26-20, 10:09 AM
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Usually the stud is removable from the boss, but why would you want to replace them?
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Old 04-26-20, 12:08 PM
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Originally Posted by madpogue
why would you want to replace them?
The bike I got for $10 and has served me well so I'm willing to invest in it. The brakes I have on the back (and the front but to a lesser degree) are both using not-entirely-safe-currently straddle cables. They're also a little unfriendly to adjust and clean so if I could replace them (which I should anyway) I figure I could go for a newer set on the back.
Now that I am aware of NOS I might also do that.
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Old 04-26-20, 01:19 PM
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I was wondering why you'd want to replace the studs. You asked about them being replaceable. They look quite serviceable.
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Old 04-26-20, 01:21 PM
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Oh the studs are fine so long as I have a locking nut or locking washer. I am not confident that they would be compatible with other brakes if I were to switch them.
As long as it's just unorthodox and not unsafe to use nuts instead of bolts for mounting then I will continue to do so.
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Old 04-26-20, 01:30 PM
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It's neither unsafe nor unorthodox to use nuts in this case. Those posts are made for them.
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Old 04-26-20, 04:31 PM
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Well I'm glad to hear that. Unorthodox in that any other canti that I've seen has been mounted with a bolt.

I cleaned them up today and they are Dia-Compe 981's. The front and back mounts are identical. I have Shimano BR-AT 50's mounted on the back with unequal springs and just enough return tension to make them usable - which is my real issue here. I have found threads on here about custom spring making but I feel it might be best to go either NOS or upgrade/update.
Is anyone familiar with compatible cantis? Would I have luck with any V brakes that mount to an oppositely-placed spring hole?
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Old 04-26-20, 05:56 PM
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If you watch on ebay, the correct springs for yours come up on ocassion. I had to buy a set for an old Mongoose frame that had outboard springs.
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