Life expectancy of rear brake caliper
 

Hi everyone,
My first posting to the forum and I suspect it's a 'how long is a piece of string' question - but here it is anyway!
After many years of driving to work, I bought a new road bike with Ultegra components back in April 07 and, bar holidays etc., have been commuting 35 miles a day (round trip), 3 days a week, ever since.
I own a Focus Cayo and have fitted SKS race blades for the winter. I rinse the bike down after every ride and give it a decent clean every 2 weeks.
For several weeks now my rear brakes have been seizing regularly. Three trips to the LBS later and we've finally decided that the caliper is shot.
Around 3,500 miles and my rear brake assembly (which I don't particularly favour - I tend to brake more with my front brake) has failed. Is this normal?
Appreciate your comments.

I think that the calipers can be shot only if they cracked. Highly unlikely.
I would first change the housing and brake cable, then check the spring.
Maybe, the wheel needs truing.

I see you wash the bike alot. Where do you live? Do you relube also? Have the alloy items on your bike crusted up?

I thought the same. Mechanically it seems a simple enough device - what can go wrong?!. The cable has been changed, spring tension adjusted as much as it can be, and the whole assembly greased. There are no bent bolts. It still doesn't work reliably.

I live in Edinburgh, Scotland. Roads are salted regularly during the winter which I'm sure doesn't help. I don't relube the calipers regularly - should I? My front brakes are used more often and get the same cleaning/(non) lubing regime, but are fine. No problems with with any other alloy components.

It's a new bike, you may have warranty.
Otherwise, Tektro www.tektro.com makes nice brakes, you can buy a set for $30-40.

Incorrect. Calipers usually fail when they no longer open or close smoothly and with enough force to push both arms away from the rim. It's easy to see if it's the cable/housing or if it's the caliper. Simply disconnect the cable and push the calipers close and feel it.

Calipers should be oiled, especially if you are riding it through winter. It is hard on everything on your bike.

Calipers are made of strong aluminum, and they don't fail easily.
I would suspect:
1) the arm spring is weak, you can adjust its tension http://bike.shimano.com/media/techdo...9830615949.pdf
2) cable jams in the cable adjusting bolt
3) the pivot bolt is bent

You can disassemble and reassemble the brake yourself, no big deal:http://bike.shimano.com/media/techdo...9830621027.pdf

The caliper is an aluminum alloy and the bolt is a steel alloy when you introduce water you are essentially
making a battery, after a while it pits and wears out the contact points and has to also contend with a
build up of corrosion particles which tightens the tolerances. On any part that is made from a different metal
with a steel hardware connecting the part together or to the frame, You should use silver antisieze or if $4.00
a tube is too expensive for you at least use grease to prevent your $1.50 bolt from attacking your $1500.00
bike!! Of course some silicone and a cable luber every 3 months will give super smooth cable operation, I like
silicone because it is super thin doesn't collect dirt like some oils but the bad part is it has to be reapplied more
frequently!!

I don't think that this kind of "battery" ruined the brakes bought in April 2007 or 10 months ago. Something is broken or bent or jammed.

I've seen corrosion kick up pretty fast in wet/salty enviroments. Put in the di-electric situation of metals and non or low use of calipers and the crust could build up in low tolerance areas. I just can't see, (unless you have some pixs?), the brake calipers going bad if they weren't abused.