It’s often tempting for us to think of our cars as a single entity, rather than a collection of many different components. It’s when one or some of those components fail that our relationship with our favorite Mustang or Ford vehicle can sometimes become a little rocky. Given that most of our favorite rides are getting on in years, components wear out and need to be replaced. And often some of the most overlooked (but vital) items include suspension pieces, like the lower front ball joints.
During the course of its life, a car’s suspension has its work cut out. It has to almost constantly cushion the blows from road surfaces and over time this regular pounding has an effect. Springs lose their tension and start to sag, while shock absorbers lose their damping ability, causing the vehicle to bounce over imperfections. As for ball joints, well if a ball joint fails, the spindle can dislodge from the lower control arm, causing the front wheels to rotate freely and a loss of steering, before bringing the car to a sudden stop. Now imagine you’re traveling at speed on the freeway when that happens – the consequences could be disastrous, which is why it’s important to take note of them and replace them as necessary, as we did on this 1988 Mustang GT convertible.
HOW A BALL JOINT WORKS
A ball joint is a spherical bearing stud and socket housed inside a steel casing. The end of the stud is tapered and also threaded where it attaches to the spindle, while the casing acts as a shield to prevent foreign matter from getting inside the bearing. The ball joint acts as a pivot point between the wheels (in contact with the road) and the vehicle’s suspension. Traditionally, ball joints required routine lubing on older cars, usually as part of a regular oil change procedure, however beginning in the late ’70s, sealed units, which were “lubed for life” became increasingly common and are now almost universal.
The problem is that on cars such as our subject Fox Mustang, sealed ball joints tend to have a shorter lifespan and wear out between 60,000 and 100,000 miles. The seals deteriorate, causing dirt and moisture to get inside the socket and rust to develop. As a result, the socket becomes loose until eventually it just gives way. You can tell if your vehicle needs new lower ball joints if the steering feels slack and you hear thud noises every time you go over a bump. However, like many basic maintenance procedures, replacing lower ball joints on your Ford or Mustang is generally straightforward, requiring tools available at any auto parts store, the joints themselves (approximately $40 each) and a few hours worth of time. In this story the folks at MRT, a renowned Detroit area Mustang specialist and performance shop, show us how to correctly replace lower front ball joints on a late-’80s Mustang GT.
1. Here’s our subject vehicle. This 1988 Mustang GT has spent all its life in the Midwestern United States. As a result it has traveled many miles on broken and potholed streets. The car is generally in very good shape and at the time of our story, boasted just over 76,000 original miles on the odometer. However during driving, the owner noticed that the steering was developing play on the left side in particular and clunking could be heard over bumpy surfaces. Time to replace the ball joints?
2. Our first task of the day was to get the car inside and on the hoist. Because the car has locking wheel nuts, MRT technician Nick Williams, opens the trunk to access the car’s factory wheel changing tool kit.
3. Next it’s time to remove the wheels. Fox Mustangs, except the 1984-1986 SVO and 1993 Cobra, came from the factory with four lug rotors, so we have the front rims off in no time.
4. Here you can see the basic front suspension hardware. Fox Mustangs utilize a Modified MacPherson strut design with the lower control arm attaching to the strut and the spring mounted inboard of it, to the lower part of the shock tower in the inner fender. The ball joint is housed on the edge of the lower control arm, underneath the spindle.
5. When you jack the car up, either using a hoist or axle stands, also make sure you use the recommended jacking points to ensure the vehicle is secure before you begin, as well as to avoid damaging the underside. On Fox Mustangs these are at the rear of the front framerails and at the back, just forward of the lower control arms.
6. Next, you need to remove the cotter pin that sits on top of the castle nut that keeps the spindle in place on the control arm. It’s location behind the front brake and dust shield means that it can be quite fiddly to remove.
7. Here’s one of our new replacement Moog ball joints, which we got from Federal Mogul. Note the tapered and threaded end of the socket where it attaches to the spindle, the heavy-duty rubber casing and also the replacement cotter pin and castle nut. When doing any work on your car, never, ever reuse old cotter pins.
8. At the bottom of each ball joint, is a small nipple that should come with them. Make sure you don’t lose it, as you won’t be able to properly grease the bottom of the joint without it.
9. The next task is to remove the brake caliper so you can pull off the rotor. Two hex bolts secure the caliper in place on the spindle and an impact gun works best to remove them.
10. You’ll want to make sure the caliper is safely tucked out of the way while you’re working on the spindles and ball joints. Nick’s solution is to use surplus coat hanger wire, threading it through the caliper at one end and securing it to the framerail at the other. This way it stays nice and secure, without causing damage to you, the fender lining or front suspension. At the same time it prevents putting unnecessary strain on the rubber hose that links the caliper to the car’s hydraulic braking system.
11. Next remove the bearing dust cap, so you can remove the outer front wheel bearing in preparation for pulling off the rotor assembly. Also bear in mind that you’ll have to repack the wheel bearings with fresh grease once the ball joints have been replaced.
12. Pull the cotter pin out, before removing the outer bearing from the hub assembly.
13. With the bearing out, slide off the rotor and put it to one side.
14. Next, you’ll need to remove the castle nut, before dislodging the spindle from the ball joint so you can access it.
15. On cars like this, which are regularly driven, several blows with a hammer will often be necessary to dislodge the spindle from the control arm.
16. Now it’s time to remove the dust shield from the spindle to gain better access to the ball joint assembly. The shield is held in place by just two bolts.
17. With it off, and having used our hammer to pry the spindle loose from the lower control arm, you can see our old ball joint. Now the real work begins.
18. In order to do this, you’ll need special ball joint removal tools including a separator, C-clamp, and adapter. These are available at most auto parts stores and come with different size collars for facilitating the removal of ball joints on different types of vehicles.
19. Using the ball joint separator, press it into the lower control arm from beneath.
20. Then fit the adapter on top and secure the clamp, slowly tightening it until it’s in line with the separator and the bottom of the control arm.
21. In some cases, if the ball joint is seized in place, due to grime and rust, you might need to use a heat gun or flame in order to pull it out of the lower control arm. If the car has been rustproofed, take great care using heat, as the presence of undercoating can easily cause a fire to start.
22. After using heat, we had to use a hammer to dislodge the ball joint, since it was so stiff, we had a difficult time just using the separator tool.
23. Finally, it came free.
24. Here you can see the old ball joint (left) alongside its new Moog replacement. It wasn’t until we pulled the old one apart that we realized how bad the damage was.
25. The ball almost fell out of the socket – note the corrosion around the bottom of the ball – definitely the right time to replace it.
26. Using the clamp and adapter, the new ball joint was pressed into the lower control arm. In order for a snug fit, considerable force is required, along with an extra pair of hands to hold the clamp steady.
27. With the ball joint in place, you can now place the dust cover over it. Make sure that it’s nice and tight – the last thing you want is for moisture and dirt to get inside your brand new ball joint, otherwise you’ll have to perform this job all over again.
28. From beneath you can see the bottom of the ball joint assembly. Remember that little grease nipple we talked about in caption 8? Here it is, installed.
29. With the ball joint in place and everything nice and tight, we can slide the spindle back over ball joint and secure it in place with the castle nut.
30. You’ll need a long wrench and a fair amount of leverage when tightening the castle nut on the top of the spindle. Make sure it’s sufficiently torqued and that a new cotter pin is installed once you’re done.
31. Here you can see the castle nut in place.
32. Once it is, you can then re-install the dust shield.
33. Followed by the brake rotor.
34. Make sure that you pack the front wheel bearings with fresh grease before reinstalling them.
35. Once the bearing is in place, install a new cotter pin.
36. Before fitting the dust cap.
37. Having cut and removed the coat wire, Nick carefully places the caliper back over the rotor.
38. Before installing the caliper bolts, make sure you lube them with a thread compound, to prevent them from seizing inside the spindle down the road.
39. Torque the bolts and you’re finished.
40. With the passenger’s side done, Nick turns his attention to the driver’s side, but in order to get at the spindle and particularly the castle nut, he needs to crank the steering wheel in the other direction.
41. Having repeated the process on the driver’s side, after a couple of hours, the front wheels were reinstalled. The Mustang is then lowered off the hoist and backed out into the sunshine. Ideally you should have front-end alignment checked as soon as possible, but even at this stage, the owner of the car already noticed a tighter feel in the steering. Job accomplished!
Federal Mogul Corporation