The second question has arrived for our new Q & A series. John W. asks Legacy Classic Trucks' Founder and President, Winslow Bent,
if "the original springs are used on [Legacy's] conversions."
Legacy uses a more modern and wider front leaf spring on our trucks. Specifically, we use one spring for gas trucks and a stiffer one for diesel trucks. In the rear we use original springs with bushing rebuild kits. From our many years of work, here are the issues we've addressed through these decisions:
Front Spring Wrap: The original suspension had limitations in the performance we were looking for, the biggest issue being the spring wrap. We found that when we upgraded to disk brakes, the torque generated by braking was great enough to "twist" the narrow front springs. This, in turn, would cause a pull on the steering drag link. Unless you would let go of the steering wheel, the truck would veer off the road, which is of course incredibly terrifying.
Rear Spring Wrap: The torque generated by our engines was enough to twist and in some cases break the main spring on the rear leaf pack. It also caused deflection in the driverline angles, which felt like a shutter when you would let the clutch out.
Bushings: The brass bushing added a lot of vibration from the road into the steering wheel.
Shackles: The front mounted shackles compress forward when the suspension absorbs a bump. This adds to a stiff and bouncy ride.
Our Solution: We replace the entire front suspension and steering and then move the steering box out infront of the axle. This allows us to do "cross-over" steering, which eliminates "bump steer" and steering shock loads. Using a custom Pitman Arm, we now have perfect geometry.
We then do a "shackle reversal" and install longer shackles mounted in the rear of the front lead pack. The entire axle now compresses inwards and up into the suspension. This works incredibly well with our shock hoops and Bilstein Shocks. We also add urethane bushings, which make the ride more comfortable for the driver and passengers.
Lastly, this new suspension allows us to add additional positive caster so that the truck wants to go straight, rather than turn. In the rear of the truck we remove the factory overload springs, which still leaves us with about 13 springs. We install new bushing to eliminate lateral deflection, make new top plates for the springs so we can add larger bump stops, and also take the time to add rear shocks. We fix the rear wrap issue by adding traction bars. The bars are .240 wall DOM tube and mounted with Heim Joints (Johnny Joints) on both ends. These can be adjusted as need be. When combined with a locker or posi, the new truck "jumps" off the line and pulls heavy loads with ease.
I suppose we could use a modern truck chassis, but I feel that would remove too much of the truck's character and integrity. I have never been a fan of "cab on scab" conversion and can always spot them a mile away.
Have a question of your own that you would like answered? Please shoot us an email at any time. We look forward to hearing from you!