1. Cracks
   Loose bolts
2. All of the above

It's always important to check leaf springs and their accessories for wear -- a worn or cracked leaf spring can cause untold damage to a trailer and its contents. When taking leaf springs off, it's a good idea to check the shackle links for wear. A round ring of wear that matches the shape of the nut is OK, but once the shape becomes an oval, it's time to replace the shackle link. <a href="http://auto.howstuffworks.com/auto-parts/towing/equipment/accessories/leaf-springs.htm">How Leaf Springs Work</a>

1. Two flat ends
   One curled end or one flat end
2. Two ends that curve up into a circle

Open-eye leaf springs have only one eye, or open hole. The other end of an open eye leaf spring can be a hook end or a flat end. <a href="http://auto.howstuffworks.com/auto-parts/towing/equipment/accessories/leaf-springs.htm">How Leaf Springs Work</a>

1. Two ends that curve up into a circle
   Two flat ends
2. One curled and one flat end

On double-eye leaf springs, the top plate -- and therefore the longest -- has both ends curved into a circle. The ends make two holes, which you can bolt to the bottom of a trailer's frame. <a href="http://auto.howstuffworks.com/auto-parts/towing/equipment/accessories/leaf-springs.htm">How Leaf Springs Work</a>

1. U-bolts
   Glue
2. Hatch lock

The purpose of the U-bolts is to keep the leaf springs flush against the axle so they take the weight of the cargo and don't move around too much during driving. <a href="http://auto.howstuffworks.com/auto-parts/towing/equipment/accessories/leaf-springs.htm">How Leaf Springs Work</a>

1. Overslung (placed over the axle)
   Underslung (placed under the axle)
2. Both overslung and underslung

The leaf springs can be overslung (placed over the axle) or underslung (placed under the axle). Either way, the U-bolts fit around the axle and secure to a metal plate that rests against the leaf springs. <a href="http://auto.howstuffworks.com/auto-parts/towing/equipment/accessories/leaf-springs.htm">How Leaf Springs Work</a>

1. Behind the wheel
   On the grill
2. On the bumper

Leaf springs are positioned behind the wheel -- you can't see them clearly when they're attached unless you crawl under the trailer -- so the wheel needs to be taken off completely before installation begins. <a href="http://auto.howstuffworks.com/auto-parts/towing/equipment/accessories/leaf-springs.htm">How Leaf Springs Work</a>

1. Support much heavier loads that monoleaf springs
   Offer improved suspension
2. All of the above

Leaf springs can improve suspensions weighted down with heavy loads. Drivers looking to tow heavier loads typically use multileaf springs, which consist of several leaf springs of varying length stacked on top of each other. <a href="http://auto.howstuffworks.com/auto-parts/towing/equipment/accessories/leaf-springs.htm">How Leaf Springs Work</a>

1. More protection than multileaf springs
   Less protection than multileaf springs
2. Breakaway prevention

Leaf springs come in several different varieties. There are monoleaf springs, or single-leaf springs, that consist of simply one plate of spring steel. These are usually thick in the middle and taper out toward the end, and they don't typically offer too much strength and suspension for towed vehicles. <a href="http://auto.howstuffworks.com/auto-parts/towing/equipment/accessories/leaf-springs.htm">How Leaf Springs Work</a>

1. Frame
   Rear bumper
2. Back bumper
   Axle

Compared to most automotive technology currently available, leaf springs don't look too fancy. They're simply long and narrow plates attached to the frame of a trailer that rest above or below the trailer's axle. <a href="http://auto.howstuffworks.com/auto-parts/towing/equipment/accessories/leaf-springs.htm">How Leaf Springs Work</a>

1. Tow heavy loads
   Prevent Breakaways
2. Prevent Tire Blow-outs

Trailers built with leaf-spring capabilities are much better at carrying heavy loads. <a href="http://auto.howstuffworks.com/auto-parts/towing/equipment/accessories/leaf-springs.htm">How Leaf Springs Work</a>