what causes 1 brake shoe to stay on rim?

have center pull brakes and this is a problem i've seen from time to
time in bikes i owned. i depress and release the brakes, this time on
the front wheel, and one shoe stays on the rim.

so frustrating! do i have to take the housing apart and replace the
spring?

On May 24, 5:14 pm, wrote:
have center pull brakes and this is a problem i've seen from time to
time in bikes i owned. i depress and release the brakes, this time on
the front wheel, and one shoe stays on the rim.

so frustrating! do i have to take the housing apart and replace the
spring?

First, I'd make sure that the caliper is cenetered, if it's a
centerpull caliper brake. If it's already centered, you might want to
lube the pivots.

If it's a centerpull cantilever, at least one side's spring should be
adjustable. Increase the tension on the pad that's sticking.

Another problem can come on centerpull cantilevers if you have a link
wire, and the guide tube for for the main cable becomes compressed.
One half of the mechanism will have more mechanical advantage, and can
cause pull imbalance. You can replace the guide tube with some cable
housing, or replace the link wire with a traditional straddle cable
and yoke.

wrote:
have center pull brakes and this is a problem i've seen from time to
time in bikes i owned. i depress and release the brakes, this time on
the front wheel, and one shoe stays on the rim.

so frustrating! do i have to take the housing apart and replace the
spring?

no, simply center the caliper correctly. there's usually a slot in the
pivot that allows a thin wrench to be used for this job.

or it's the wheel not positioned correctly.

either way, real simple.

wrote:
have center pull brakes and this is a problem i've seen from time to
time in bikes i owned. i depress and release the brakes, this time on
the front wheel, and one shoe stays on the rim.
so frustrating! do i have to take the housing apart and replace the
spring?

Center wheel in fork first. Lubricate the centerbolt thread, torque
properly then move the bridge (not the arms) it will stay centered.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

A Muzi wrote:
wrote:
have center pull brakes and this is a problem i've seen from time to
time in bikes i owned. i depress and release the brakes, this time on
the front wheel, and one shoe stays on the rim.
so frustrating! do i have to take the housing apart and replace the
spring?

Center wheel in fork first. Lubricate the centerbolt thread, torque
properly then move the bridge (not the arms) it will stay centered.


Same for brakes on my MTB, except they are sidepull. Every time I
remove & replace the front wheel. the brakes are in a different spot and
the blocks are usually rubbing - always need adjustment of the springs.
What gives?
Bob C

--
Posted via a free Usenet account from http://www.teranews.com

Bob Chambers wrote:
A Muzi wrote:
wrote:
have center pull brakes and this is a problem i've seen from time to
time in bikes i owned. i depress and release the brakes, this time on
the front wheel, and one shoe stays on the rim.
so frustrating! do i have to take the housing apart and replace the
spring?

Center wheel in fork first. Lubricate the centerbolt thread, torque
properly then move the bridge (not the arms) it will stay centered.


Same for brakes on my MTB, except they are sidepull. Every time I
remove & replace the front wheel. the brakes are in a different spot and
the blocks are usually rubbing - always need adjustment of the springs.
What gives?
Bob C



Friction in the pivots.

Lou
--
Posted by news://news.nb.nu (http://www.nb.nu)

wrote:
have center pull brakes and this is a problem i've seen from time to
time in bikes i owned. i depress and release the brakes, this time on
the front wheel, and one shoe stays on the rim.
so frustrating! do i have to take the housing apart and replace the
spring?

A Muzi wrote:
Center wheel in fork first. Lubricate the centerbolt thread, torque
properly then move the bridge (not the arms) it will stay centered.

Bob Chambers wrote:
Same for brakes on my MTB, except they are sidepull. Every time I
remove & replace the front wheel. the brakes are in a different spot
and the blocks are usually rubbing - always need adjustment of the
springs. What gives?

Lou Holtman wrote:
Friction in the pivots.

That's possible, but more likely on a cantilever. Some cantilevers pivot
on the frame's boss. Remove brake assembly (one side at a time!), emery
post and sleeve, then lubricate well on installation.

Other cantilevers, like linear brakes, have an inner sleeve which stays
in place; a bronze sleeve in the arm pivots on the stationary steel
sleeve. Those are harder to deal with when corroded but the effort pays
well. You'll need a small press to separate them, emery all surfaces
then lubricate well on installation

Sidepulls benefit from oil on all mating surfaces including the end of
the spring where it slides on the arm's peg (In Jobst's pithy analysis,
'cosine error'). Like classic centerpulls, the arms 'float' on the
spring(s) so the centering mechanism is the position of the spring slot
in the centerbolt. Merely moving the arm is futile; the bolt's attitude
to the horizontal must be adjusted. Better sidepulls provide wrench
flats to achieve that; They are easily added with a file. Later Modolo
style centerbolts and copies (Shimano) offer a broached end socket for
an allen key.

As in all brake centering difficulties, slip your fingers aside the tire
or rim on both sides simultaneously before touching the brake itself.
More often than not the wheel is to one side.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

have center pull brakes and this is a problem i've seen from time to
time in bikes i owned. i depress and release the brakes, this time on
the front wheel, and one shoe stays on the rim.

so frustrating! do i have to take the housing apart and replace the
spring?

It might not be the spring or even the brake itself, but rather a
severely-worn rim that now has a lip near the top of it (sometimes the pads
themselves can also be worn in such a way that they sort of hook into the
rim). Brake pads will sometimes catch on such lips and not want to
retract.Generally this only occurs when you're not actually riding the bike.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com