The following information was supplied by the John Bean 5 series alignment machine. The information is not meant to be passed as being my own and all credit goes to the John Bean company and it's associates. Information I add will be notated as follows: *** Text ***
Suspension Systems:
-Control Arms
-MacPherson Strut
-Ball Joints
-Stabilizer Bar
Every vehicle manufactured relies upon some type of suspension design for motion control and directional navigation. These basic designs are the Short Arm Long Arm (SALA) and the MacPherson Strut systems. There are countless variations of these principle designs, so only the basics will be discussed. For specific application material, refer to the vehicle repair manual.
-Control Arm suspension
This is commonly referred to as short arm/long arm (SALA) due to the upper control arm being shorter to allow for inward positioning of the upper ball joint for SAI. During bounce and rebound the upper control arm moves over a greater angle causing more sideways movement at the top of the tire than at the bottom. This keeps the tires flatteron the road during cornering lean. The arms are held to the frame with bushed shafts or bolts. These shafts allow movement of the control arms in the up and down arc. Usually the upper control arm is used for adjustment of the camber and caster. This adjustment can be slot adjustments, cams or shims.
-SALA Adjustments
The SALA suspension systems rely on basically three types of adjustment for the CAMBER and CASTER.
1) Shims may be used between the control arm and the vehicle frame to space the control arm to the desired position.
2) Slots are also used to allow movement, and the control arm is then secured in place with bolts.
3) Cams at the pivot point may be used to force the arm to the proper position. Usually all three types of adjuster provide movement at both the front and the rear of the control arm. To change camber only, move the front and rear in or out the same amount. To change caster only, move the front and rear in opposite directions by the same amount.
-Control Arm Bushings
Always inspect the control arm bushings in their natural position, with wheels on the groun. Look for obvious deterioration and breakage. Make sure the bolt or shaft is going straight through the center of the bushing. If not centered, they could cause variations in alignment angles during driving. When replacing these bushings, do not tighten completely until vehicle is lowered to its normal ride position. This will assure the bushing does not have a twist which will lead to premature wear.
-MacPherson Strut
The MacPherson strut is a clever design using fewer parts to reduce costs. The MacPherson is generally made up of a shock absorber, spring, and upper bearing plate which rotates when turning. This unit takes the place of the upper control arm, so most alignment adjustments are made here. To inspect for failure, look for oil leaks or bends in the rod. Check the vehicle for bounce and rebound, the vehicle should not bounce more than two and one-half times.
-Ball Joints
The ball joint is a ball with a tapered stud, a housing and a bearing surface. This allows the ball to move in a circle or in an arc, but not in or out, much like a shoulder joint. Most suspension systems use ball joints at th some point to allow a circular motion. Ball joints are usually either compression or tension loaded joints. The compression loaded means that the weight of the vehicle will push the ball into the housing. The tension type will be pulling the ball away. In either case the ball will be in constant contact with the bearing surface. Usually the load carrier or compression joint will be the one closest to the spring or torsion bar. The other will be the followerer.
----Checking the Ball Joint
------Checking for Axial Play
Before checking, the ball joint should be unloaded (have weight removed from them). The conventional SALA system locates the weight carrier on the lower control arm. The spring or torsion arm also makes contact here. Place a jack under the lower control arm and lift until the tire just clears the floor or rack. Place a dial indicator base on the control arm, with the dial placed on the steering knuckle. Zero the dial. While moving the tire up and down, read the dial change and check to see if it is within manufacturers specs. Some other tupes of modified strut place the spring or weight carrier on the upper control arm. These are checked by jacking vehicle by the frame and placing a suitable wedge, available from alignement tool manufacturers, to hold the arm away from the frame.
------Radial Ball Joint Checks
Note: Any play in the wheel bearing will be included in the radial measurement. To avoid this, apply the brakes or tighten the bearings.
Lift the vehicle until the tire just clears the floor. Place the base of the dial indicator on the control arm and dial touching the wheel rim. Zero the dial. Hold the tire at the top with one hand, and the bottom with the other. Push in with one and pull out with the other, alternating in and out. Note the difference in dial readings.
------Wear Indicator Ball Joints
Many late model vehicles use a "wear indicator" load carrying type ball joint. This design allows checking of the joint without lifting, or use of dial indicators. Before checking, clear the area around the grease fitting of any dirt or excess grease. The fitting is screwed into a boss or plate with a 1/2 inch nipple, which protrudes about 0.050 inch beyond the surface when good. As the joint wears the nipple recedes. If it is flush or inside slightly, the joint is worn and should be replaced.
Note: This type of joint should be checked in the "dry park" position, or resting on the floor with full weight on the tires.
-Stabilizer Bar
The stabilizer bar, or sway bar, is used to keep the vehicle level by transferring forces from one side of the vehicle to the other. When cornering or driving on an uneven surface, there is a weight shift which causes vehicle lean or change in ride height from side to side. This change could cause changes in the camber and toe settings. A properly sized stabilizer bar will improve the handling of most vehicles by reducing sway. The stabilizer bar is attached to both lower control arms and is also secured to the frame with bushings. These bushings should be checked for damage, deterioration, or looseness. Some vehicles use the sway bar as a strut rod.
Suspension Systems:
-Control Arms
-MacPherson Strut
-Ball Joints
-Stabilizer Bar
Every vehicle manufactured relies upon some type of suspension design for motion control and directional navigation. These basic designs are the Short Arm Long Arm (SALA) and the MacPherson Strut systems. There are countless variations of these principle designs, so only the basics will be discussed. For specific application material, refer to the vehicle repair manual.
-Control Arm suspension
This is commonly referred to as short arm/long arm (SALA) due to the upper control arm being shorter to allow for inward positioning of the upper ball joint for SAI. During bounce and rebound the upper control arm moves over a greater angle causing more sideways movement at the top of the tire than at the bottom. This keeps the tires flatteron the road during cornering lean. The arms are held to the frame with bushed shafts or bolts. These shafts allow movement of the control arms in the up and down arc. Usually the upper control arm is used for adjustment of the camber and caster. This adjustment can be slot adjustments, cams or shims.
-SALA Adjustments
The SALA suspension systems rely on basically three types of adjustment for the CAMBER and CASTER.
1) Shims may be used between the control arm and the vehicle frame to space the control arm to the desired position.
2) Slots are also used to allow movement, and the control arm is then secured in place with bolts.
3) Cams at the pivot point may be used to force the arm to the proper position. Usually all three types of adjuster provide movement at both the front and the rear of the control arm. To change camber only, move the front and rear in or out the same amount. To change caster only, move the front and rear in opposite directions by the same amount.
-Control Arm Bushings
Always inspect the control arm bushings in their natural position, with wheels on the groun. Look for obvious deterioration and breakage. Make sure the bolt or shaft is going straight through the center of the bushing. If not centered, they could cause variations in alignment angles during driving. When replacing these bushings, do not tighten completely until vehicle is lowered to its normal ride position. This will assure the bushing does not have a twist which will lead to premature wear.
-MacPherson Strut
The MacPherson strut is a clever design using fewer parts to reduce costs. The MacPherson is generally made up of a shock absorber, spring, and upper bearing plate which rotates when turning. This unit takes the place of the upper control arm, so most alignment adjustments are made here. To inspect for failure, look for oil leaks or bends in the rod. Check the vehicle for bounce and rebound, the vehicle should not bounce more than two and one-half times.
-Ball Joints
The ball joint is a ball with a tapered stud, a housing and a bearing surface. This allows the ball to move in a circle or in an arc, but not in or out, much like a shoulder joint. Most suspension systems use ball joints at th some point to allow a circular motion. Ball joints are usually either compression or tension loaded joints. The compression loaded means that the weight of the vehicle will push the ball into the housing. The tension type will be pulling the ball away. In either case the ball will be in constant contact with the bearing surface. Usually the load carrier or compression joint will be the one closest to the spring or torsion bar. The other will be the followerer.
----Checking the Ball Joint
------Checking for Axial Play
Before checking, the ball joint should be unloaded (have weight removed from them). The conventional SALA system locates the weight carrier on the lower control arm. The spring or torsion arm also makes contact here. Place a jack under the lower control arm and lift until the tire just clears the floor or rack. Place a dial indicator base on the control arm, with the dial placed on the steering knuckle. Zero the dial. While moving the tire up and down, read the dial change and check to see if it is within manufacturers specs. Some other tupes of modified strut place the spring or weight carrier on the upper control arm. These are checked by jacking vehicle by the frame and placing a suitable wedge, available from alignement tool manufacturers, to hold the arm away from the frame.
------Radial Ball Joint Checks
Note: Any play in the wheel bearing will be included in the radial measurement. To avoid this, apply the brakes or tighten the bearings.
Lift the vehicle until the tire just clears the floor. Place the base of the dial indicator on the control arm and dial touching the wheel rim. Zero the dial. Hold the tire at the top with one hand, and the bottom with the other. Push in with one and pull out with the other, alternating in and out. Note the difference in dial readings.
------Wear Indicator Ball Joints
Many late model vehicles use a "wear indicator" load carrying type ball joint. This design allows checking of the joint without lifting, or use of dial indicators. Before checking, clear the area around the grease fitting of any dirt or excess grease. The fitting is screwed into a boss or plate with a 1/2 inch nipple, which protrudes about 0.050 inch beyond the surface when good. As the joint wears the nipple recedes. If it is flush or inside slightly, the joint is worn and should be replaced.
Note: This type of joint should be checked in the "dry park" position, or resting on the floor with full weight on the tires.
-Stabilizer Bar
The stabilizer bar, or sway bar, is used to keep the vehicle level by transferring forces from one side of the vehicle to the other. When cornering or driving on an uneven surface, there is a weight shift which causes vehicle lean or change in ride height from side to side. This change could cause changes in the camber and toe settings. A properly sized stabilizer bar will improve the handling of most vehicles by reducing sway. The stabilizer bar is attached to both lower control arms and is also secured to the frame with bushings. These bushings should be checked for damage, deterioration, or looseness. Some vehicles use the sway bar as a strut rod.
