Bicycle Mechanics - Brake install question

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Drexman
02-20-07, 08:43 PM
I have an older 80's steel framed road bike that I have converted to a SS. The bike has older Shimano single pivot side pull caliper brakes. When I reinstalled the front brake, it does not seem to be clamping on both sides. In other words, when I engage the brake lever, only one brake pad pulls toward the rim. The other pad remains still.
I adjusted the front center bolt and tried different cable routings. What am I doing wrong?
astrodaimler
02-20-07, 09:12 PM
Does it have a washer against the fork that looks like a toothed cog?
Drexman
02-20-07, 09:29 PM
No, it does not. I installed that washer on the back side of the fork facing out with the toothed part against the nut. Should it be installed on the front of the fork with the toothed part against the fork?
Thanks for the help.
thePest
02-20-07, 10:56 PM
Very Very common problem...
Traders trick:
a.) A high quality pivot bolt will have what looks like a slot. You may not have the offset tool for it. They come as 10-11 or 12-13. If you are lucky and it's a 13? You can go ahead and use a cone wrench between the breakspring and th efork.
b.) this is the most common way. Take a punch and place it onto the spring towards the top. if looking righ at it. say the pad drags on the right. Place the punch on the left side of the spring near the top. Just give it a tap till it is centerd.
c.) Also Weinmann invented a two prong tool you sneak into the loops. But I would use b.) For I did for 35yrs!!!
tellyho
02-21-07, 07:12 AM
I think what I'm going to say may echo thePest, but I can't fully visualize what he's saying. My solution to this problem has always been to adjust the spring on the side that is not moving enough. On the side where the pad is NOT moving, use a screwdriver to lever the spring out from it's perch. Then bend the spring out away from the fork, giving it more tension. Push it back into position. You should have balanced the spring action a little more in the process.
Of course, if the toothed nut belongs in front, ignore the above.
astrodaimler
02-21-07, 10:11 PM
Hi Drexman,
Got your email. Yes the cog washer needs to be like this: allen_bolt--bridge--cogged_washer--caliper--springs--etc..etc..
Initially, having the cogged washer there, you can pretty much center it by hand before you tighten the allen bolt and carefully hold the whole unit centered while tightening the allen. The Shimano should (not completely sure) have an 11mm flat bolt somewhere around near the cogged washer and calipers. There was a tool back then called the Park Centering tool and that was just using the 11mm and twisting it. As I recall, the proper method was to use the 11mm tool while tightening the allen bolt.
Part II on "thePest"s reply works also but he's correct, do Part I first. Part II was with really old calipers without a slotted 11mm.
HTH.
Drexman
02-21-07, 11:51 PM
Yes the cog washer needs to be like this: allen_bolt--bridge--cogged_washer--caliper--springs--etc..etc.
Thanks for all the help. Last question (I hope) - when you say bridge you mean either the rear brake bridge or the fork? If so, shouldn't there be some sort of washer between the allen bolt and the bridge/fork?
astrodaimler
02-22-07, 07:30 AM
Thanks for all the help. Last question (I hope) - when you say bridge you mean either the rear brake bridge or the fork? If so, shouldn't there be some sort of washer between the allen bolt and the bridge/fork?
The rear is the bridge and the front will be the fork. The allen bolt goes inside the bridge and inside the fork area so there shouldn't be a washer in there.
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