Thread: Hard suspension

Originally Posted by discojools

I have 110 D250 on airbags a year old now. Always thought my suspension is very stiff. Have compared with a friends Defender and a couple of others which are much smoother. Have tried to demonstrate to my dealer but very hard to do in suburban streets. They have checked the venting which is in spec. Took a friend to the LR 4x4 show yesterday and he is also suspicious of the ride. He said it was nothing like the demonstrator that I drove him in. Just don’t know where to go from here. Will have to get the dealer to bring a demo down to me so that I can show them the difference. Wish me luck! Apart from that I love the car.

You'll need to consider a few other factors:

- What wheel size are you running?
- What tyre? Have you changed them?
- What pressures are they running at?

Then theres.. What model was the demonstrator? Bigger (heavier engine)? What spec?

The kerb weight, tyre pressure, rubber type all have a bearing on how the bags perform - the venting isnt particularly relevant when driving - only the struts valving comes into play during most of that.

Running 18s with factory Adventurers at factory recommended pressures. The demo was a D300 and a P400, both were substantially more comfortable. My neighbour has a D250 110, sightly older than mine better ride than mine despite the BFG KM2s. Also friend with D300 110 which we have tested back to back and both think mine is too stiff.
Feels like stiff dampers to me. I believe they are adjustable, otherwise why the wires out of the top of them.

The shocks are indeed CVDs. Abnormal ride harshness with CVDs can be caused by a loose or faulty height sensor or a loose or faulty accelerometer which may appear to the suspension and CVD ecus to be producing valid signals therefore no fault codes are posted. Displaying wheel heights and articulation can be useful as the one sensor serves both suspension height and the damper systems. A valve in a shock can also be faulty but providing the coil isn't open circuit, it won't be considered faulty.

Its of no use disconnecting 1 shock at a time trying to find a faulty one because the whole system is disabled if any 1 is disconnected.

On older vehicles such as the MY10-12 L322, ride harshness is usually caused by a faulty height sensor but because those vehicles use a twin sensor, 1 for ride height and another for CVDs, watching ride height displays can be inconclusive, although usually the fault is that the linkages partially sieze making the arm movement erratic.

Probably should update this thread with the information that the chassis module was proven and subsequently accepted by LR to be faulty, not powering the bypass valves in the shocks. A replacement chassis module fixed the issue.

Originally Posted by Graeme

Probably should update this thread with the information that the chassis module was proven and subsequently accepted by LR to be faulty, not powering the bypass valves in the shocks. A replacement chassis module fixed the issue.

Interesting, do you have the part no for the chassis module and the fault identifications from LR by sny chance?

I find my 23.5 P400SE suspension also very stiff, and i have not ever seen the suspension adapt in over 12000km of driving on various surfaces. Wondering if im having the same issue as described.

The part numbers are different depending on the vehicle specs although probably only the s/w configuration rather than the hardware.

The tell-tale sign was no increase in ride harshness with an electrical connector detached from a shock (any shock, so detach a front one to test) as this disables the whole CVD system. Subsequently an IIDtool was used to display and record live values showing that no current was being drawn by the shocks even though other live value displays showed that the shocks were supposedly being softened. A helpful LR dealer then repeated the monitoring with his LR diagnostic tool, LR specialists got involved and eventually a replacement chassis module was ordered.

The ride transformation with a working module was magic carpet stuff. A module out of a new vehicle was tried which fixed the ride but caused too many errors for the module to be left fitted.

OK, so I disconnected the right front CVD and went for a drive
The dash warning around suspension fault came up as expected, however car was able to proceed. Ride was much harsher than normal, so I don't believe I have an issue with the CCM. I dont have a GAP tool yet to record live values, so will check again when the G4 Iid BT tool arrives.

I suppose the suspension feel is subjective, i do run my tyres around 40-41 psi cold, so may try lowering those to see what difference that makes.

Thanks for the tip.

Sometimes 2 psi can make a big difference to the ride.