Tiagra brake lost it's 'spring'

guybat

My rear Tiagra brake has lost it's 'spring'. Not literally, all are parts present and correct - but it doesn't spring back in on itself as it should. I've taken it apart, cleaned it; the actual coiled spring thing looks tarnished, and doesn't slide into it's little black plastic widget smoothly.

Is it just knackered, or is there a trick to regain it's spring, or a bit that needs particular care/lubrication?

pbiggs

The cable could be in need of cleaning, lubing or replacing. (Note though that some cables are prelubed or not meant to be lubed). Outer cable shouldn't be too long or short either.

Also try lubricating the ends of the spring.

<i>~Pete</i>

guybat

Cables are all fine. It's the actual brake itself that's not springing back outwards when you manually close it. I'll try lubing the spring ends.

Unknown

I am assuming here that when you say that it has lost it's spring, the caliper is remaining closed (i.e. against the rim) after you have operated and released the brake lever. If you look at the caliper from the front, there is an allen key screw on the right hand side of the caliper. This will be 'factory set' to a certain depth and tension, to allow the caliper to operate properly. If this screw tightens (which is possible through normal use), it pushes the front and rear arms of the caliper together, stoppingit from springing back to the open position. This screw is normally set with loctite at the correct depth, but prolonged use can loosen the loctite, and cause the screw to tighten. Try loosening the screw a quarter turn at a time (right to left), and you should see the caliper spring open. HTH.

If at first you don't suceed, deny all knowledge of ever trying!!!

pbiggs

Cable friction can stop the brake itself springing back, so double check the cables are OK.

The screw on the side of a dual-pivot brake is for fine tuning the centering.

The actual pivot(s) may be stiff (and can be adjusted, see Park Tools) but I would make sure nothing else is causing the problem first.

<i>~Pete</i>

guybat

Thanks all. I've taken it off the bike to inspect more closely. It's definitely semi-seized or jammed at one of the pivots. I can get a new one for œ14, but I'd just like to figure out how/why it's stuck.

The Park website is good, but I'm nervous about taking the spring out. One broke once on a brake I was dismantling, and shot across the room, just missing my eye.

pbiggs

Assuming dual-pivot.....

The side pivot is easy to adjust and doesn't require taking the spring out. Loosen nut at rear, adjust pivot at front with allen key, tighten nut.

The central pivot is much bigger job, but give the side one a go first if you think that might help.

Liberally oil both pivots as well - with ordinary general purpose oil.

guybat

I took the offending brake into those lovely chaps at Apex Cycles in Clapham High Street, who hit it with large blunt objects, bathed it in WD40, and managed to prise the stuck centre pivot back into play, not something I could have done at home.

And charged me a beer. Hoorah for LBS's!