I used:

Timac Spring Manufacturing Inc.
825 Bellbrook Ave.
Xenia, OH 45385
(937) 372-3305

That was in Sept. 2012. Great service and great price. I sent them my old spring and they made 10 new ones...identical to what I sent. I think some other bolters have used them as well.

Good luck!

~ Victor
1941 3/4-Ton Pickup (in process). Read about it in the DITY Gallery
1955 Grumman Kurbside "Doughboy" 235/3 on tree w/ OD
1957 3100 - moved on
1959 C4500 Short Bus "Magic Bus" - moved on
1959 G3800 1 Ton Dually "Chief" - moved on
1958 C4400 Viking "Thor" ~ moved on to fellow Bolter