Front brakes not braking evenly

[stuf99]

Hi
So I was at the state inspection yesterday and I was informed that my left front brake brakes 35% less than the right one. I was told that some lubrication of the brakes may do the job. But how do I check if this will do the trick? My first thought was to drive on a gravel road and brake hard, and then see of they brake at the same spot. I have tried it now before lubing, but I can't see that they brake unevenly, maybe its the ABS that interferes with this strategy...?
Anyone got other tricks up they sleeve?

[ex-x-fire]

Remove front wheels and push the caliper pistons in with a C clamp. They should go in with steady pressure. If not the piston might be sticky or might have a restricted brake hose. Pads should move freely in brackets, its common for them to rust in place. Caliper pin get frozen too.

[WeeYari]

If you are not experiencing the car pulling to one side when braking then your caliper pistons are probably ok.

My money is on your caliper sliders (pins) seizing. This is usually the first thing to contribute to uneven pad wear. Without being regularly cleaned and lubed, they eventually dry out or gum up. When this happens, the pads do not return to a "floating" state over the surface of the rotor upon release of the brake pedal.

[stykerdk]

In danish.
Det er 99% sikkert dine glidere der ikke kører som de skal.
Der er en fin video her på autodoc hvor de skiller dem ad, der må endelig ikke komme for meget fedt på gliderpindene.
Så komprimerer de fedtet inde i hullet og laver en fjedereffekt, så trykker den uens på klodserne.