I didn't see an option to adjust brake force while driving in the LFS manual or in any of the setup screens.
The problem is that rarely the " squash ball" under my brake pedal will shift not allowing enough pedal movement thus limiting brake force in a race..
If you can't get enough pedal movement, you could also try recallibrating the pedal in LFS with that respective option. Just push the brake as far as you want to push it after pressing recallibrate and it will use that maximum from then on.
It will shift and NOT allow enough pedal movement? I have the opposite. My pedal is VERY stiff from the squashball mod and it still has full range. But it will shift completely off to the side away from my brake pedal.
I started using very high braking force in my setups. Reason being is I now only use about 25% of the movement. It is very stiff and very hard to push through the entire range, and it now feels more like a pressure sensitive pedal with using the squashball and larger braking force.
And I don't really have the squashball mod. It's more of a half cut down raquette ball mod, hehe. Maybe that is why I still have full range of my pedal movement.
I've got a cut down foam rubber smilie face ball that I got from work.
The problem I have is that sometimes things do shift/crack or I'll change setups and realize in race that I should have dialed in a little more or less force (in the middle of a 15 lapper of course). It would be nice to be able to adjust while driving instead of by trial and error. Not realistic of course though....