Check for wear on the running surfaces of the ball joints by turning the ball pin by hand. Free movement of the finger or its sticking is unacceptable.
A more accurate check of the state of the ball joint by the value of the radial and axial clearance is carried out on the fixture. To do this, install the ball joint 1 (pic. 4-6 A) into the socket of the fixture and tighten it with a screw. Install indicator 2 in the fixture bracket so that the indicator leg rests against the side surface of the hinge body, and the indicator needle is at zero.
Pic. 4-6. Checking the ball joint on the fixture:
1 - ball joint;
2 - indicator;
3 - torque wrench;
4 - fixture;
A - scheme for checking the radial clearance;
B - scheme for checking the axial clearance.
Install the torque wrench 3 in the upper socket of the tool and apply a torque of 196 Nm to it (20 kgf·m) in both directions, use indicator 2 to determine the total radial clearance in the ball joint. If it exceeds 0.7 mm, replace the hinge with a new one.
Similarly, check the axial clearance in the ball joint, after changing its fastening in the fixture, as shown in fig. 4-6 V. Axial clearance in the hinge is allowed no more than 0.7 mm.
Suspension springs. Carefully inspect the springs. If deformations are found that may cause a malfunction, replace the springs with new ones.
To check the spring settlement, squeeze it three times until the coils touch. Compress the spring along the axis of the spring; the bearing surfaces must correspond to the surfaces of the bearing cups on the vehicle suspension. Then apply a load of 6276 N to the spring (640 kgf). Along the length of the spring (see fig. 4-7) under the specified load are divided into two classes: class «A» – length over 192 mm and class «IN» - length equal to or less than 192 mm. Springs class «A» may be unmarked or marked with white paint on the outer side of the coils, class springs «IN» marked with black paint.
Pic. 4-7. Basic data for checking the front suspension spring.
Install springs of the same class on the front suspension as installed on the rear suspension. In exceptional cases, when springs of class «IN», and there is no such class of springs for the front suspension, then it is allowed to install springs of the class «A». But it is not allowed to install class springs on the front suspension «IN», if the rear suspension is equipped with class springs «A».
Check the technical condition of the insulating gaskets and replace them if they are damaged.
Stabilizer, suspension arms, steering knuckle. Check if the rod is deformed and if its ends are in the same plane; if the deformation is insignificant, then straighten the bar; in case of significant deformation, replace the rod.
Carefully inspect and make sure that the suspension arms, cross member and steering knuckles are not deformed or cracked. If there are cracks or deformations, replace the indicated parts.
Suspension crossbar. Check the geometric parameters of the cross member with a control device. If the cross member is significantly deformed, when it is impossible to adjust the angles of the front wheels with washers, and if all other suspension elements are in a satisfactory condition, replace the cross member.
Rubber-metal hinges. Signs of the need to replace rubber-metal joints are described in subsection «Determining the condition of the front suspension parts».