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for the second ride in a row, my rear caliper has stuck itself fully on, as in bringing the bike to a halt and not being able to move it an inch......after a minute or so, the ride can continue and I get home without using the rear brake. Hardly use the back brake anyway as it's so rubbish, no noise from it, new pads last year, pedal all lubed up.......any ideas what I should be looking for tomorrow?

cheers for all the advice guys ;)

Probably some dirt/corrosion on the piston, stopping it from retracting properly, then the heat from braking causing everything to expand and seize on. Try removing the caliper, pumping the pistons out (a bit - not too far or they'll fall out), and cleaning with some spray cleaner and a soft cloth. Push the pistons back, and re-fit.

When you fitted the pads did you clean the paint off the top and bottom edges so the pads slid into place nice and smoothly.
Or did you have to tap them in with a knocking stick.
If you had to knock them into position, the pads will stick in the slides and cause the problem you have just mentioned.
Clean the paint off and put a little bit of copper grease on the edges being carefull not to get any on your friction matierial

top tips - I've got a bit lazy over here as the labour costs are soo cheap, the mechanic fitted the pads, so I'll take a look at that one myself....

Good advice from Blinkey.
If the pads dont drop into place easily then you cant expect them to push out and then return without problems, Ive had to file the edges of the steel backing material to remove paint and rough edges

Before you start stripping it, how full is the fluid? It's a common fault (I've had it!) that if it's over filled, the heat from the rear header expands the fluid and hence such pushes the pistons out and your brakes on. May just need some fluid sucking out. Hope it helps.

bigun wrote:Before you start stripping it, how full is the fluid? It's a common fault (I've had it!) that if it's over filled, the heat from the rear header expands the fluid and hence such pushes the pistons out and your brakes on. May just need some fluid sucking out. Hope it helps.

What he said.

This is the usual cause of that problem

Wot they said, but also make sure there's a couple of mm play at the plunger, if it's up against the piston you can get what you described

Be careful when you extend the cylinders out that the reservoir doesn't empty. I stupidly didn't keep an eye on it last time and the first I knew about the master cylinder sucking in the air was when it sounded like it was having sloppy seconds with a dutch hooker (no offence to the dutch).

Now my rear brake doesn't work as I've not got round to bleeding it through yet, yes I am that lazy :)

blinkey501 wrote:When you fitted the pads did you clean the paint off the top and bottom edges so the pads slid into place nice and smoothly.
Or did you have to tap them in with a knocking stick.
If you had to knock them into position, the pads will stick in the slides and cause the problem you have just mentioned.
Clean the paint off and put a little bit of copper grease on the edges being carefull not to get any on your friction matierial

Funnily enough I was just cleaning the bike and noticed the rear disc was looking a bit "blued"!? Took out the pads, there seemed to be a "blueing" on the pads too, possibly been dragging?

Anyway cleaned the caliper,pistons and pads putting everything back together, I thought the pads didn't seem to slide into the caliper too easily.
Decided too clean the edges as descirbed by your good self. Looks like I may have caught this one before it happend!