Brake looks fine but doesn’t stop wheel when riding??

[BrakeGrief]

My sons bmx brake looks fine. I’ve taken into a shop and they said it looks fine. When you squeeze the break just holding the bike it stops the wheel, but when someone is sitting on the bike it just doesn’t. The brake is really stiff to pull as well. I have replaced brake lever with a longer one and oiled cable on advice of shop person - but it’s still no better.
I tighten it right up to the point where you can only just re fix the cable to the wheel part of the mechanism and it still doesn’t stop the wheel when there’s a persons weight on the bike. What the heck is going on here?

 

[Drago]

Degrease the rim, new cables, new blocks (compatible with the rim material and finish), job done.

 

[Dave Davenport]

Does the brake operate via a gyro (a system mounted just under the handlebars that allows them to swivel right round without twisting the cables)?
Braking performance is on a scale of poor to non-existent if it has one of those, best to remove it and run the cables direct.

 

[Cycleops]

Sorry about your problem. Not saying your bike is but some of these BMX bikes have poorly made and ineffective brakes. Could you please post a pic so that we can see what is involved. As @Dave Davenport says could be the headset mounted cable detangler might be having effect although I've never found this personally.

 

[BrakeGrief]

Hi, thanks for the responses. I can’t post pics because I’ve only just registered (to find help with this issue!).
It’s not a gyro. It’s a direct brake system like on my road bike, but it almost feels like there’s not enough give in it? Like when you squeeze the brake lever it doesn’t move much. I’ve tried adjusting the brake pads which has had zero effect. I’m at my wits end because it’s putting my son off riding :-(

 

[BrakeGrief]

I’ll try degreasing rims and getting new brake pads - though the ones on look ok, and the shop guy thought they looked ok too.

 

[HLaB]

Is it the back or front brake, the back brake should slow you down gradually but may not actually stop you (use it for control); the front brake should actually stop you. The correct balance is what you want there. As time goes on I favour the front brake more but be cautious of that if he's new to cycling.

 

[Cycleops]

You can post a link to a photo sharing site.

It's not cool to have a front brake on a BMX is it ?

 

[fossyant]

New cables too

 

[Nigelnightmare]

Is it a real BMX or a BMXSO with pressed steel brakes.

 

[Deleted member 26715]

I saw a young girl yesterday come around a corner & ride straight into a fence, when she got up she was riding a BMX with no brakes at all.

 

[Globalti]

It needs a new cable. Outer and inner.