JJ i agree with Kurt, as you know a lot of us are running the new style m4's and have had no problems with them what so ever, they look, perform and feel great. all my experiences with avid have been bad, and i know Brett has got a set of codes instead of his m4's , but they too feel really spongy and crap TBH. If the reliable local bike shop is the one i am thinking of and his bleeding hasn't solved it then ask him to check it over for you and explain in depth about whats going wrong, he should be able to help you out. failing that if you do need to settle and get a new set of brakes then id advise a set of hopes or something along the lines of shimano as they too are pretty reliable in my experience.

Right, I just dropped it off at the shop, well, it's partner shop. I explained the issue, and we are beginning to think its a problem with the either the diaphragm or master cylinder. Good call Dezmtber!

I will have it back on Tuesday with any luck, I'll let those who were too seeking an answer; (Sarah**)

It's a shame, especially considering how much potential the brakes have, hopefully this could have just been a small defect in a certain batch, as my front one has been perfect.

JJ

Edit: Does anyone know if I can fit a metal lever blade to this brake? bar straightline and dangerboy, looking for something short, has anyone retrofitted a hayes / hope blade?

If you've got plastic lever blades, you've been mugged when you bought the brake...

Avid's come with metal blades as standard, I've NEVER seen one with plastic blades that'd be f'ing ridiculous.

Rootes

I'd be VERY surprised if they were plastic.  Sounds odd though, I've run juicy's since they were released and never found them flexy.

I'm running straitline blades at the moment because I couldn't get new avid blades after snapping one in a crash, they're short and comfortable.  But no stiffer than the avid blades were.

Rootes

http://www.southerndownhill.com/forum/index.php/topic,166693.0.html

Hayes, but another story. It might help.

Rich

Have you hit them in a crash at all?  Marginal bending in an accident would explain the marks.

As for less modulation, make sure they're properly bled, if you still want sharper power then braided hoses might be the way to go, Avid don't recommend them because they're not made by Avid...and apparently make the brakes feel more wooden, ie. less modulated.

Rootes

Could be stress marks as you need to pull his brakes mofoing hard for them to ever start touching the rotor. although jj im sure there metal yours dont feel or even look as if there plastic.