Technical Support
How to Replace a Valve Block on a Discovery 3
How to Replace a Valve Block on a Discovery 3
The fifth generation Discovery was released in 2014 and offered a range of new features including a more powerful and cleaner diesel engine.discovery 3 valve block The new model also featured a more sophisticated interior, a range of safety and driver assistance technologies as well as a one speed transfer box which replaced the old two speed design. A computer controlled progressively locking central differential was also fitted to aid with traction.
One of the more common problems with these models is a faulty valve block which can result in sagging and other air suspension issues.discovery 3 valve block Often the cause of this is due to the small metal particles that circulate around the system during operation. These can clog the solenoid valves or simply wear them down. This is usually an easy fix for a DIY owner, with the right tools and a couple of hours the job can be done in a garage or driveway.
Located underneath the passenger side wheel on the chassis is the front and rear valve blocks.discovery 3 valve block There are six solenoid valves inside these which control the flow of air to and from the air reservoir and the wheels. Each of the valves are activated by a signal from the air suspension control unit. Air is supplied to the valve block from the air compressor, then fed to the valves by two outlets connected to each of the wheel suspensions.
When one of the valves becomes faulty or wears down it will cause the pressure in the gallery to reduce and the wheel to deflate, or in some cases to leak excessive air into the compressor which can damage it.discovery 3 valve block Normally the sensor inside the valve block will report back to the ECU that one of the solenoids has stopped working. This is a good sign that it is time to replace the valve block.
Before you start working on the valve block it is best to lay it out flat in a clean area and get the tools ready. A large selection of spanners, screwdrivers and pliers are needed along with some cleaning fluid and rags. A crotchet needle and brass wire are also useful for removing the o-rings.
It is also worth taking the time to study the diagram of the valve block as a refresher before starting work. This will help you to understand how the system works and what flows in and out of each of the solenoids.
The first step is to remove the fuse which governs the air suspension. This will disable all calibration through the night and will allow you to more accurately pinpoint the faulty component. Then it is a case of loosening the air lines (3x 12mm brass fittings) and carefully letting the air out. Once the bags are deflated, you can pull out the valve block (held in with rubber feet, no bolts) and pop a new one in place. Once it is inserted you can connect the air lines and test the system, if it is sagging or not it is most likely the fault of a faulty valve block.
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