Fix It

A ball joint links the console arms of the front and rear suspensions to the wheel hub assemblies of your vehicle. In some vehicles, the ball joints connect all components of the suspension.

Significance

Rear ball joints are sometimes used in vehicles that are front-wheel drive and have independent suspensions. In some newer vehicles, the rear suspension is assembled with ball joints to link all parts of the suspension together.

Function

The ball-and-socket design of the ball joint provides swivel room for the knuckles of the joint as the wheels of the vehicle are steered. It also allows the suspension to handle changes in the road as the vehicle is moving.

Considerations

If there is a problem with the ball joint, you might hear a knocking noise when your vehicle goes over small bumps in the road. Erratic steering and wandering are also indicators of problems with the ball joint.

A U joint, or universal joint, is a type of connection used in many applications, but primarily in a car or trucks drivetrain. The universal joint takes its name from the ability of the joint to move in any direction.

Locating the U Joint

Most rear-wheel drive and four-wheel drive trucks have two universal joints on each end of the driveshaft. The driveshaft runs from the transmission to the rear differential and works to convey power from the engine to the wheels.

U Joint Appearance

The universal joint itself is cross-shaped, but when connected, the joint is identified by the U-shaped end of the driveshaft where it connects to the U-shaped end of the transmission and rear differential.

Common Problems

As a universal joint wears out, it often will make a metallic thump when the truck is placed into drive or reverse. This is due to the driveshaft taking up the slack in the joint. Worn universal joints also may cause the driveshaft to spin out of balance. An out of balance driveshaft may vibrate when the transmission is engaged.

A broken CV joint can propel your Subaru right off the road. Its a part well worth the time and effort to replace. A 1993 Subaru Legacy has CV axles in the front and rear of the vehicle, depending on the model. The most efficient way to replace a CV joint is to replace the entire CV axle with a new or re-manufactured axle. The front CV axles are more difficult to replace due to the more complicated front steering and suspension assembly, but most aspiring do-it-yourselfers should be up to the task.

Instructions

Preparing to Remove the Axle

1

Park the car on a level surface and set the emergency brake. Make sure the Subaru is parked in third gear or higher if it has a manual transmission. Slightly loosen the lug nuts. Do not jack up the vehicle.

2

Remove any covers over the axle nut (also called the spindle nut, it is located at the center of the wheel on the end of the axle). Pry or beat out any indentations in the slotted portion of the axle, using a straight screwdriver. Spray penetrating oil on the nut if any rust is present. Then, using the breaker bar and a six-point socket of the correct size, break the axle nut free, but do not remove it.

3

Jack up the vehicle and lower it onto a jack stand. Make sure the vehicle is safely supported--you are going to have to crawl underneath it. Remove the wheel and the axle nut.

4

Unbolt the sway bar bracket from the lower control arm. Remove the cotter pin and castellated nut from the lower ball joint. Separate the lower ball joint from the steering knuckle with a ball joint separator. Remove the lower control arm the rest of the way by unbolting it at the two points immediately above where the sway bar bracket was attached.

5

Remove the cotter pin and castellated nut from the tie rod where it attaches to the steering knuckle. Use the tie rod separator to remove the tie rod from the steering knuckle; then push the detached end of the tie rod out of the way.

6

Crawl underneath the vehicle and locate the retaining pin that passes through the axle where it joins the transmission or front differential. Using a hammer and a small punch or a Phillips-head screwdriver, pound out the retaining pin.

Removing and Reinstalling the Axle

7

Remove the CV axle from the end at the transmission. Use a flat screwdriver or another suitable prying tool to separate the axle from the transmission or front differential.

8

Remove the axle from the steering knuckle using the axle puller.

9

Slide the new axle through the steering knuckle, and install the new axle nut. Tighten it by hand for now.

10

Align the axle retention pin holes on the new CV axle and the transmission end. Slide the new axle into place at the transmission end and install a new retention pin.

Finishing the Job

11

Re-install the lower control arm, tie rod and sway bar bracket. Using the torque wrench, tighten the nuts on the lower control arm to 113 Nm, according to the 1993 Subaru Legacy repair manual published by Chilton Library.

12

Tighten down the castellated nuts on the tie rod and ball joint, and install new cotter pins.

13

Torque down the new axle nut--the torque figure for this nut is 186 Nm, as also specified by the 1993 Subaru Legacy repair manual. Using a hammer and screwdriver or punch, score the outside of the axle nut at the keyed portion on the axle.

14

Put the wheel back in place and tighten down the lug nuts. Raise the vehicle, remove the jack stand, and gently lower your Subaru to the ground. Re-tighten the lug nuts.