Ford lovers are a fiercely loyal bunch with a lifelong commitment to the Blue Oval. They love Ford for its rich history, and yet at the same time condemn Ford for some of its notorious engineering efforts. Ford did its share of design work with budget in mind—such as upper control arms void of grease fittings from the factory that ultimately doomed shock towers from the start.
Because Ford car buyers were unaware of this issue, they never anticipated the consequences.
Cracked and broken shock towers are common with the classic Mustang, Cougar, Falcon, and Comet primarily. Enthusiasts blame shock towers—however, this has never been the reason shock towers crack and break. Shock towers fail because upper control arm bushings have seized up, which has worked shock towers back and forth (known as “oil canning”) until they crack and fail. It is like bending a piece of metal back and forth until it snaps. When upper control arm bushings and shafts fuse together, the shock tower does all the flexing until it gives out.
Upper control arm bushings are a solid metal on metal relationship between the bushing, which is attached to the control arm, and the shaft, which is attached to the shock tower. Given adequate lubrication, they work quite well together. Because car buyers never gave any thought to upper control arm bushing/shaft lubrication, deterioration has only gotten worse with time. The bushing and shaft grind against one another until they become fused together to become one.
Once shock towers crack and break, they must be replaced with stronger aftermarket shock towers with proper reinforcements that will enable them to perform under the most grueling conditions. You may also add “big-block” reinforcements, which were used on big block and BOSS Mustangs. Scott Drake reproduction shock towers from Summit Racing are equal to original equipment and protected from corrosion with EDP coating for lasting corrosion resistance. As long as you keep upper control arm bushings lubricated, these shock towers will last a lifetime.
Shock tower replacement is not easy nor for the faint hearted. You will need to pull the engine because the shock tower and brackets are significant structural members that also support the engine and transmission. You will need a spot weld cutter, an assortment of drill bits, clamps, and a wire-feed welder, which can be rented. Of course, there are other tools you’re going to need.
Jim Smart is a veteran automotive journalist, technical editor, and historian with hundreds of how-to and feature articles to his credit. Jim's also an enthusiast, and has owned and restored many classic vehicles, including an impressive mix of vintage Ford Mustangs.