Just throwing this into the pot,but how about stuffing the coils with a close cell foam rubber,maybe securing them with zip ties?
It might act a little like a shock absorber and remove some of the bounce.....

Well you did say you wanted a cheap fix....... grin


1950 Chevy Advance Design 3100 in Scotland
In the Stovebolt Gallery
More pix on Flickr.
I've definately got this truck thing in my blood ... my DNA sequence has torque settings
"Of all the small nations of this earth,perhaps only the ancient Greeks surpass the Scots in their contribution to mankind" Winston Churchill.