[Land-speed] bounce

[bobbyhotrods at comcast.net]

Alright all you grouchy old farts, I can't think of a better bunch to bounce this query off. 
I finally ran my roadster last weekend at Loring, and had a great time btw. Surprisingly, there were no major issues and the car performed better than the guy making the decisions. 
But braking after the lights resulted in the front tires bouncing. The more brake, the more bounce. 
The front is dampened with friction shocks, and I'm pretty sure I replaced the rubber with fresh sheeting when I built the car some years back. Yeah, I can tighten them, but they weren't loose. 
Does any lister have any experience on what works best with these things? McMaster Carr has a variety of rubber sheeting, and I can put any finish necessary on the "washers", or even on the rubber I suppose. Even a good guess would be appreciated, thanks, BJ