I have just bought some second hand 7s.
I have put the rear on my bike and blead it.
Does anyone understand what the red wheel does and how you set it up?

I have screwed it fully in and fully out with the Allen keyed adjuster in and out.
And there doesn't seem to be much going on at the lever.
I can't find owt on the SRAM site.

I have noticed that the Allen adjuster gets dragged around at one extremity of red wheel adjustment and this may be working against each other.

The grub screw is the lever reach adjuster & each click of it results in 1mm of lever travel (either towards the bars or away, depending on how which way you turn it).

The red screw is the contact pad adjuster and should adjust how much lever travel there is before the pads contact the rotor. You should notice it with new pads particularly. At one ond of the travel, there'll be virtually no lever movement before the pad bites, whereas at the other end the lever will move a long way before the brakes start working.

Are you sure you set the brakes correctly before bleeding? I can't remember exactly, but think that the reach adjust grub screw needs to be wound out with at least 3 full threads showing before you bleed the brakes.
There's a great video from Avid on You Tube that demonstrates bleeding.

Violence is the only language they understand. Seriously. Just punch them like you mean it before trying to do anything with them.

Yes, I checked out both the vidoes(Keaeau & other) and they say two threads and wheel fully out.I may try again but the lever feels good at the moment.
BD Are you replying to my thread? Surely inanimate objects cannot bring forth such feelings?