Have got '08 Ultegra shifters on road bike.

When I pull the rear brake lever I get no real power. Can hear slight dry/creaking sound coming from within lever, so sprayed WD40 to loosen things up a little. Also cleaned the rear wheel rim really well with water and a washing up sponge, spotless now. But no joy. Still no real power.

All cables last changed 1 year ago, bike not ridden at all through winter, only ridden again since things got drier back in March.

Any thoughts?

On mtb would usually just lube/replace cable, but don't know how to change cable on road bike. Does it involve removing bar tape?

Either cable or seized up rear caliper; take the wheel out, try squeezing the caliper by hand; if it's not the caliper then replace the cable.

You can replace the cable without taking off the bar tape if you know what you are doing, but taking the tape off is not a big job..

I don't bother removing the tape when I change my brake cables. It is easy enough to feed it through the outers.

crikey, what do i do if it's a seized up rear caliper?

Don't worry dude it's not as bad as it sounds – just take it apart, clean it, lube it and put back together. Just a couple of allen bolts. Take note of where each bit goes as you dismantle it.

You don't need to remove bar tape to change the inner cable but if you wanna change the outer you'll need to. It's possible the inside of the outer has corroded causing "stickiness" in the cable movement.

I never manage to change the inner with the outer in situ without fraying the end trying to find the outer opening .I give up and take it all off

well…you could take it to bits, but I'd just drown it in WD40 or something similar and keep squeezing it by hand til it gets the message!

Might be best to take the brake blocks off,.

I never manage to change the inner with the outer in situ without fraying the end trying to find the outer opening .I give up and take it all off

A new cable should have a sealed/soldered end so shouldn't fray when you try and feed it through the outer.

A new cable should have a sealed/soldered end so shouldn't fray when you try and feed it through the outer.

Correct, just never cut a new inner cable until it's clamped, they certainly shouldn't be fraying.

Taking the calliper apart isn't quite as easy as that ^^.

My Tiagras need a 13mm spanner, a 10mm spanner, a silly tiny allen key for the little grub screw underneath, and then you have to fiddle about tightening things just right so they don't bind and aren't too loose.

Takes half an hour, the park website has a good guide to it.