Disassembly
- Secure the front suspension strut and, using a special device with grips, compress the spring so that it moves away from the upper plate (Fig. 14.27).
Fig. 14.27. Using a special device to compress the front suspension shock absorber spring
Warnings
- (1) Install the special devices symmetrically and so that its maximum length does not exceed the installation limits.
- (2) Do not use an air impact tool to tighten the bolt of the special spring compressor, otherwise the special tool may be damaged.
- Secure the shock absorber rod with a wrench to prevent it from turning and use a second open-end wrench to loosen the central nut securing the shock absorber rod (Fig. 14.28).
Fig. 14.28. Unscrewing the central nut securing the shock absorber rod
Warning: To avoid loosening the piston rod lock nut, do not use an impact wrench.
- Remove the shock absorber damping support, upper spring plate and upper spring pad from the shock absorber rod.
- Remove the spring together with the spring compressor, the rubber compression buffer and the lower spring pad.
- Loosen the tool bolt until the spring is fully extended and remove the tool from the spring.
Shock absorber disposal
- Pull the shock absorber rod out completely.
- To remove gas from the shock absorber cylinder, drill a 3.0 mm diameter hole in the location shown in Figure 14.29.
Fig. 14.29. Location of drilling a hole for removing gas from the shock absorber cylinder
Note: The gas escaping from the shock absorber is safe, but care must be taken to avoid injury from flying chips.
Examination
- Check the strut support bearing for wear or damage.
- Check rubber parts for damage or deterioration.
- Check the coil spring for deflection and loss of elasticity.
- Check the shock absorber as follows:
a. Grasp the shock absorber rod with your hand and push it in and out of the shock absorber several times;
b. Check that the piston rod moves smoothly, without sticking, and that the force applied to the piston rod does not change with each stroke;
c. Make sure that there is no extraneous noise when moving the rod.
Assembly
- When installing, it is necessary to use springs with the same technical characteristics (with the same color marking) on one axle of the vehicle.
- Install special tool MB991237 and MB991238 on the new spring and compress it to install it on the shock absorber.
Warning: Do not use an impact wrench to tighten the special tool bolt as this will cause the bolt to lock.
- Install the compressed coil spring so that its lower end is correctly positioned in the lower spring pad.
- Install the rubber compression buffer, upper spring plate and strut damper support, then temporarily tighten the shock absorber rod mounting nut.
- Align the holes in the lower and upper spring support plates. This job is easily accomplished using a length of pipe as shown in Figure 14.30.
Fig. 14.30. Using a piece of pipe to align the holes in the lower and upper support plates of the strut spring
- Correctly align both end coils of the spring with the grooves in the upper and lower plates, then loosen and remove the special spring compressor.
- Use a wrench to prevent the shock absorber rod from turning and use a second open-end wrench to tighten the central nut securing the shock absorber rod to the required torque (see Fig. 14.28).
Warning: To avoid loosening the piston rod lock nut, do not use an impact wrench.
- Apply general purpose grease to the front strut damper bearing (Fig. 14.31).
Fig. 14.31. Location of the front strut damper support bearing
Warning: Be careful when applying grease; do not allow grease to come into contact with the rubber elements of the damping support.