9/16 x 3 1/2 Inch Spring Bolts are used on nearly all types of heavy duty land and boat trailers. The 3 1/2" Length is also very common on trailers with 6,000 lb and 7,000 lb axles with 2" Wide Leaf Springs.
These 9/16 inch Spring Bolts can be purchased along side the leaf springs and equalizer bars. These bolts are raw steel, and are splined to allow a secure fit. The nuts are self locking and must be installed with the grooves(shown) out.
Feel free to check the measurements on your spring bolts before purchasing or call us if you need any assistance.