Ball joints are the hardest working suspension part. They move up and down with every bump and swivel left and right with each turn. The front, lower ball joints have the toughest job because they must rotate while supporting the weight of the car. It’s not surprising therefore that the lower ball joints are among the fastest wearing and most frequently changed of suspension parts.
For many decades before ball joints, cars had straight-axles up front and it was up to kingpins to support the front wheels while allowing them to turn. Straight-axles and kingpins are still around. They are easy to view on many street rods and they often still do the heavy lifting under large trucks. Although kingpins can support a lot of weight they only allow one axis of movement and are difficult to replace. Still, many auto manufacturers continued using kingpins even after advancing to independent front suspension. Ball joints finally replaced kingpins on 1955 Chevrolets and made their debut on Corvettes in 1963. C4s have the upper ball joint riveted (with four rivets) but switched to pressed-in lower ball joints. The later generations have pressed upper and lower ball joints. A ball joint press is needed to remove the pressed ball joints when the A-arm is on the car but using the press is generally faster and easier than removing (or installing) rivets.
Unlike other suspension components, ball joints were originally riveted to the A-arms. These original rivets can be removed via a grinder, chisel, drill or saw, but if the lower ball joints were previously replaced, which is common, the job is even easier. The new ball joints can be bolted in or attached with bolts whose heads look like rivet heads. Special fixture tools are also available to install rivets to preserve originality.
Before starting on ball joint replacement, it’s wise to inspect the rubber bushing on the A-arms. If they show a lot of wear, a lot of time and labor can be saved by removing the A-arms to replace these bushings and ball joints at the same time.
Fortunately, ball joints are easier to change than the kingpins of C1 Corvettes and other antique suspensions. No special tools are required other than a simple pickle fork (and that inexpensive tool often can be borrowed from auto parts stores). Replacing ball joints can be accomplished at home without a lift. And if you want to break up the task, ball joints can be changed one at a time or one side at a time. Follow along as we detail the weekend project and provide tips not found in the factory service manuals.
1. It’s easy to inspect the lower ball joints. Place a jack under the lower A-arm close to the wheel and raise it up and until the tire is off the ground. Use a board or long rod as a lever to pry the tire up and down. If any movement or clearance is seen at the ball joint, it should be replaced. Check both sides. A broken seal or intrusion of water and road grime can make one side wear much faster.
2. It’s easier to break the lug nuts loose while the tire is still on ground. If the car is already jacked up, an assistant is needed to hold the brakes to keep the wheel from spinning.
3. Battery powered electric impact wrenches are surprisingly good and convenient to use. Although not as powerful as air impact wrenches, they don’t have an air hose getting in the way.
4. Tip: Placing a 2x4 on the outside of the floor jack enables the pressure to be applied as far out as possible while still allowing room for removal of the ball joint. This compresses the spring further, which is beneficial to the job. It’s obvious that this ball joint was previously replaced because it’s attached by bolts not rivets. That makes replacement a lot easier.
5. The only special tool that is needed is a pickle fork, also called a splitter. Be aware that they come in different sizes. The forks on the tie-rod end splitter are so close together that they won’t fit over the lower ball joint shaft. A local auto parts store offered three different size pickle forks for use. Tip: Test the fork on the new ball joint to make sure it will work.
6. Remove the cotter pin and castellated nut from the lower ball joint. The splitter needs to go between the spindle and the body of the ball joint. Strike the splitter with a heavy hammer until the spindle pops down. Tip: Save your hand; hold the splitter shaft with a pair of pliers.
7. Tip: Leaving the lower nut connected by a few threads keeps the heavy spindle/rotor assembly from crashing down when it breaks free from the lower ball joint. After it is broken free, remove the lower nut and then, if needed, push down on the upper A-arm to get the spindle to clear the ball joint stud.
8. Push up on the spindle assembly or pry the upper A-arm up and place a block under it. This provides easier access for removing and replacing the lower ball joint. Remove the upper nut and the two bolts to complete removal of this ball joint.
9. The rubber of the upper and lower bumpstops deteriorates and cracks over time. Replacement is fast and easy while changing ball joints. Both are available from Zip Products. Also available is a set of bolts for the lower bumpstop.
10. Zip Products also offers special ball joint bolts with rivet heads for an original look. The rivet head goes on the outside, with the nut and lock washer on the inside. The set of rivet bolts, lock washers and nuts come in two sets: four to attach both lower ball joints and six to attach both upper ball joints.
11. This is the original style ball joint available from Zip Products that features the correct stud, correct rubber boots with metal retainers and correct style casting. The rivet bolt and new rubber bumpstop is also shown.
12. The upper ball joint was riveted to the A-arm and therefore was original. It had over 300,000 miles on it, which goes to show that the upper ball joint has a much easier life than the lower ball joint, which had been replaced several times.
13. The narrower tie-rod end splitter actually worked better to separate the upper ball joint. The spindle assembly is already connected to and supported by the lower ball joint. The upper control arm rubber bumpstop is a little easier to replace after the ball joint is removed.
14. A reciprocating saw from Harbor Freight (or Sawzall) with a fine tooth metal cutting blade works well to saw off the rivet heads. If available, an air impact hammer with a chisel bit makes rivet removal much faster.
15. Center punch and drill the rivet shaft to make tapping them out easier. Tip: Use a high-speed steel drill bit (marked HSS), a low drill speed and cutting fluid.
16. If needed, tap a scraper or chisel between the ball joint body and the A-arm to help extract the rivets. Eye protection is a must for any of these hammering operations.
17. After the upper ball joint is removed, raise and block the upper A-arm for access to the bumpstop. Tip: The rubber of the new bumpstop is fairly stiff so it helps to apply a little rubber lubricant or soap to its lower flange to insert it fully into the frame. If that’s not enough, trim a little rubber from the flange with a razor blade.
18. The upper ball joint is attached to the A-arm using the Zip Products rivet style bolts. Note: the three holes in the ball joint and the upper A-arm needed to be enlarged with a 5/16-inch drill bit. The job is almost completed; just pump grease into the new ball joints and reinstall the wheel.
19. Zip Products offers special tools for installing ball joint rivets. The air hammer bit has a concave end to match the radius of the rivet head. This lower ball joint rivet fixture (tool) is attached to the underside of the A-arm by a bolt through one bumpstop bolthole.
20. The upper ball joint rivet fixture is attached to the underside of the upper A-arm by the ball joint’s stud nut. This fixture also requires the use of the special air hammer bit. The rivet shaft is driven down into the upper surface of the fixture where it expands and flattens forming the inner head.
21. Unpainted ball joints are common on restored cars. At the factory, unpainted ball joints were riveted to painted A-arms. However, the finish on factory A-arms wasn’t as nice as this.
22. If the A-arm bushings are worn, this is a good time to replace them. Remove, bag and mark where the shims go on the upper A-arms, then tap the studs out (necessary only if the body is on the frame). The lower A-arm unbolts easily but requires removal of the shock absorber and spring. A long pry bar can reset the spring during installation.
Photography by John Pfanstiehl