It’s years since ive adjusted any and on my sons bike on the rear brake only one of the legs seems to be moving and one is binding on a bit.
How do I go about sorting that?
It’s a pretty new bike, under a year it’s an Isla beinn 24 so I think the brake just needs adjusted rather than being goosed.
He’s got a race tomorrow night too, help!

There are two weeny screws to adjust tension on each arm, down by pivot. You can wind one in/out more than the other.
Check that the cable is clean.

There should be a little screw on each of the arms. This is used to adjust the spring tension. Either back off the one opposite the arm that isn’t springing back or tighten the one on the arm that isn’t springing back.

Screw some extra spring tension in on the ‘sticky’ canti arm. If that fails take it off and give the pivot a clean and lube before reassembly.

Sod that for a carry on. Unhook the wire on the sticky side, bend it out the way away from the arm then hook it back in.

Remove brakes from the studs, clean and grease the studs, reassemble then adjust, the amount of new bikes that used to come with no grease on the brake studs was silly, and caused no end of trouble with adjusting.

so either take apart, clean, grease, reassemble properly and adjust from there……
or unclip the spring and bend it for more tension.
the approach for you depends on time or OCD level

Before you do any of the above, check that you haven’t worn a lip on the lower edge of the pad where it may overhang the rim, as this often causes them to stick. a coarse file will take the offending lip off.

Soobalias – my OCD is fierce but I’m leaving early doors for work tomorrow so fiddling with screws had to do, it seems to have fixed it so thanks to you all for the help.
I’ll report back tomorrow with his race result!