Overhaul
WM 433037 Disassembling and assembling front air-spring strut
Tools
Information
As of a mileage of 200,000 km (125,000 miles), it is recommended that the air springs be replaced on each axle if there is damage to one air spring.
If the vibration dampers are leaking, the complete air-spring strut must be replaced. The oil from the vibration damper can damage the convoluted air bellows.
When depressurised, the air spring must not be twisted. There is a danger that the convoluted air bellows inside the air spring will be damaged by bending or folding, thereby significantly reducing the service life.
Disassembling and assembling spring strut
Notes
The greatest possible care and cleanliness, as well as perfect tools are important requirements for carrying out perfect repairs on air-spring struts. The general and basic rules of safety apply. These are specifically listed here again for repairing air-spring struts.
- Thoroughly clean the connection points and their surroundings before loosening them.
- Do not use fibre-shedding cloths.
- Do not take spare parts out of the packaging until right before installation.
- Only use lubricants that have part numbers.
- Carefully cover open components or close them if the repair work will not be carried out immediately.
- Do not use an impact bolter.
- Observe correct tightening torques. -> 43 Tightening torques
Gaskets, sealing rings
Always replace sealing rings and bellows.
After removing gaskets, examine the contact surfaces on housings for burrs and damage.
Tools and materials
Torque wrench 60-100 Nm (44-74 ftlb.)
Socket-wrench insert 3186
Disassembling and assembling spring strut
Air-spring strut
Overview of air-spring strut
Overview of air-spring strut
1. Carefully clamp the air-spring strut on the lower mounting (use aluminium protective jaws).
2. Loosen the fastening nut on the vibration damper -6- using socket-wrench insert 3186 and carefully remove the air spring -5-.
Removing/fitting spring-strut mount (shown as an example)
3. Remove clamp.
Clamp on boot/bellows (shown as an example)
4. Slide the boot/bellows downward and secure it (2nd mechanic required!). Hold the rolling piston -1-. Carefully press the two clips outwards -arrows-.
Clips on air spring
Carefully remove the rolling piston from the shock absorber (vibration damper) in an upward direction by turning it slightly to the left/right.
Air-spring strut rolling piston
5. When replacing the air spring, slide the additional spring -1- out of the centring device.
Additional spring (shown as an example)
6. Remove boot/bellows.
Information
If the shock absorber is not replaced, the sealing ring must be replaced.
- Make sure that everything remains absolutely clean. The smallest impurities can cause leakages.
- Clean the contact surfaces of the sealing rings with a lint-free cloth.
- Lightly grease sealing rings with Syntheso Glep 1 (Part No. 000.043.204.68).
After carefully examining all components for leaks, the spring strut is assembled in reverse order.
Information
When replacing the air spring, always replace the boot/bellows.
After removing gaskets, examine the contact surfaces on housings for burrs and damage.
Always loosen and tighten screws or nuts crosswise for mounting covers and housings.
- When sliding in the rolling piston, the convoluted air bellows must lie evenly between the outer guide and rolling piston (roll fold).
Pull the boot/bellows down fully following assembly and clip them in.
Observe correct tightening torques. -> 4X00IN Tightening torques for front axle 4X00IN Tightening torques for front axle