Replacing Residual Pressure Retaining Valve (RDHV)

Replacing residual pressure retaining valve (RDHV)





Preliminary work
1. Set the vehicle to the high level. Clean the area around the residual pressure retaining valve using high pressure cleaning equipment. When doing this, cover the air bellows (rubber) -arrows- with a metal sheet (shop-made).





Air bellows

2. Remove persistent dirt using a plastic wedge (do not use wire brushes or metal objects for cleaning!).
3. Dry the area around the residual pressure retaining valve thoroughly using compressed air.
4. Switch off the levelling system (described in "Lifting the vehicle") and raise the vehicle. The wheel remains fitted on the vehicle!

Tools and materials

Tools and materials
Torque wrench 2-10 Nm (1.5-7.5 ftlb.)
Socket insert T10158/1
Insert part T10212
Materials
^ Screw plug (Part No. N.904.142.01)
^ Pump flange cleaning agent 250 ml (Part No. 000.043.300.57)
^ Wax spray can 400 ml (Part No. 000.043.30058)

Replacing

Replacing residual pressure retaining valve (RDHV)
The residual pressure retaining valve may only be replaced if:





Removing/fitting residual pressure retaining valve

1 - Residual pressure retaining valve
2 - Socket insert

- it was damaged during removal and installation,
- it was damaged while disassembling and assembling the air-spring strut,
- the sealing ring is faulty,
- it does not allow any more air to come out (valve jammed),
- there is obvious corrosion around the residual pressure retaining valve at the air spring -7-.

If the residual pressure retaining valve is jammed, the vehicle must be lifted on the platform lift to facilitate replacement and the wheels must be allowed to turn freely.
1. Remove the pressure line at the residual pressure retaining valve -(arrow)- using insert part T10212.





Warning
Vehicle is lowered when air line is loosened
^ Risk of squashing

-> When loosening the residual pressure retaining valve, raise the vehicle on a lifting platform.
-> Only leave the vehicle on the lifting platform until a new residual pressure retaining valve is installed and the air-spring strut is filled.

Information
If the residual pressure retaining valve breaks off when being removed and/or there is severe corrosion around the residual pressure retaining valve, the air spring -7- must be replaced.
^ Do not take spare parts out of the packaging until just before installation.





Exploded view of air-spring strut

2. Remove the residual pressure retaining valve using socket insert T10158/1.
3. Seal the bore in the residual pressure retaining valve using the screw plug. If necessary, clean again using the cleaning agent, as described in the section on Preliminary work Steps 1 - 3.
4. Mask the area around the -marking-. Spray the marked area with a mist of wax. Then unscrew the screw plug and screw in the residual pressure retaining valve IMMEDIATELY and tighten to the prescribed tightening torque.





Waxing residual pressure retaining valve around the marking

5. Fit the pressure line at the residual pressure retaining valve -(arrow)- using insert part T10212.





Subsequent work

Information
The air spring must not be compressed with empty convoluted air bellows.

1. Fill the air-spring strut.
2. Lower the vehicle and switch on the levelling system (described in "Lifting the vehicle").