Member Since: 10 Mar 2021
Location: Nicosia
Posts: 92
Suspension Woes - What should I test?
Good afternoon kind people,
Seeking for some advice yet once again.
It’s a D3 2.7 TDV6 Auto HSE (2006).
The car has gradually over the past 5-6 days developed a very stiff/hard suspension ride.
No faults, no warning lamps, no bongs. Ride height works fine in all three modes and I can see it rising and lowering as normal but driving the car especially at low speeds I can feel even the slightest thing on the road. The front seems to be a bit harder than the rear.
The car has recently undergone front lower arms, steering racks, front bearings, 4-wheel alignment, and about 300miles later fitted with new Pirelli Scorpion AT+ (255/55R19) all around. The problem started developing about 3-4 days after the tires were fitted and I have calibrated the suspension using the GAP IID Tool twice and with no difference at all.
I have been reading on the forum that this is more likely to be the shock absorbers gone bad but was wondering if anyone can give any advice as to what tests/live values I can carry out with the GAP tool to see if everything else is working as it should?
Another thing I have come across is that this might be the cross-link valve of the front and the rear valve blocks which I have ordered the seals/O-rings (repair kit) and have it sitting at home, so have that covered in case this is the issue.
TIADiscovery 3, TDV6, HSE, 2006
GAP IID BT Tool
22nd Oct 2021 2:41 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4939
When this harsh ride occurs what position is the terrain selector in, and what height is being indicated by the susp height switch at this point?
The crossover valve only becomes active in "off road" mode.yµ (idµ - eAµ) ψ=mψ
22nd Oct 2021 3:14 pm
AndreasG
Member Since: 10 Mar 2021
Location: Nicosia
Posts: 92
It was in normal/road selection in terrain response and in normal height.
It wasn't specified in the posts I already read that the cross-over valve is active only in off-road height so thank you for that!
I tried driving the car in access mode today and at normal heigh at the moment the car is harder/stiffer than that. it also sounds like a broken top mount when going over pot holes or speed bumps.
(Don't know if these suspensions sound the same -as a non air suspension car- or if its the same type of top mounts that are fitted)Discovery 3, TDV6, HSE, 2006
GAP IID BT Tool
22nd Oct 2021 6:15 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4939
I think you need to get it on a ramp and check the suspension for damage.yµ (idµ - eAµ) ψ=mψ
22nd Oct 2021 7:00 pm
AndreasG
Member Since: 10 Mar 2021
Location: Nicosia
Posts: 92
Just a quick update,
Did not get the chance to check suspension parts but noticed that the vehicle lowers at the rear (self-levels?) every time I switch it off and lock the car. It lowers down around 1-2cm (I'm assuming by looking). I have not measured it. This happens when I close the doors and the blowing/hissing valve sound goes off.
Don't know if this helps at all but just thought I'd mention itDiscovery 3, TDV6, HSE, 2006
GAP IID BT Tool
26th Oct 2021 2:35 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4939
It's normal behaviour, the front and rear valve blocks will attempt to level the car when parked.yµ (idµ - eAµ) ψ=mψ
26th Oct 2021 2:46 pm
AndreasG
Member Since: 10 Mar 2021
Location: Nicosia
Posts: 92
Should the front be doing something similar too?
This happens only on the rear sideDiscovery 3, TDV6, HSE, 2006
GAP IID BT Tool
26th Oct 2021 2:56 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4939
Yes, but to a much lesser extent and only if there is a discernable imbalance. Weight over the rear is much less when the car is unloaded, and so it more prone to movement/articulation.yµ (idµ - eAµ) ψ=mψ
26th Oct 2021 3:08 pm
AndreasG
Member Since: 10 Mar 2021
Location: Nicosia
Posts: 92
Hi,
First of all, thank you PROFSR G for taking the time to reply. seems that slowly I'm eliminating probable issues and hopefully will find a solution.
anyways, I managed to check everything under the vehicle and nothing seems broken or out of place.
Further info is that the car seems to be knocking (feeling harder) intermittently. Some days it's much more noticeable than others but haven't figured out if there is any common denominator to this. It's also much more noticeable when going over something diagonally rather than in a right angle; e.g a speed bump.
I took a screenshot of some live values last night after driving home from work (around a 20minute drive). The car was resting in P, on a level surface with the engine running.
Was not quite sure as to what reading I should have taken so I took anything that seemed familiar from reading various posts from here. Again without being an expert does the gallery pressure seem quite low? Was reading that it should be around 1750Kpa???
Thanks
P.S. I've also booked a 4 wheel alignment for Saturday to get the car done again in a proper way as I was not read up properly according to the manual the previous time it was aligned. (was not in tight tolerance and did not calibrate the steering angle sensor) but not sure if this has much to do with the stiff ride
Discovery 3, TDV6, HSE, 2006
GAP IID BT Tool
2nd Nov 2021 11:46 am
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4939
Yeah that all looks OK but you need to activate the suspension height settings in order to see what each component is doing!! The screen shot shows everything at "idle"!!! In any case if there's no dtc's I would think it unlikely you have any issues with that system.
One thing you should check though with your IID is the steering angle sensor calibration! Its under "Calibration" in the menu, just make sure the car is on level ground and wheels straight ahead. Follow the on screen prompts.
Having said that, if you're going for 4 wheel alignment you must do the steering calibration afterwards anyway. In the meantime you could give it a go and see if she plays any better. It's easy stuff and only takes 2 mins.
By the way, don't get too hung up on "tight tolerance mode", if the car is sitting level on the ramp before the adjustments begin that's more important! TT helps, but it's not critical if the car is level.
If things don't improve after all that there may be an issue with the valve blocks, but first things first!yµ (idµ - eAµ) ψ=mψ
2nd Nov 2021 6:19 pm
AndreasG
Member Since: 10 Mar 2021
Location: Nicosia
Posts: 92
Thanks for all the info!
in order to check on non-idle do I just rise the suspension from access to off road and take the readings then?
Also isn't 123kPa too low compared to the 1750kPa i've been reading about or is there a reason for that (being idle perhaps?)?
I've read up on the alignment so hopefully that will make a difference. I've booked at the same place where the LR dealer takes their vehicles for alignment so hopefully the guy knows what he's doing.Discovery 3, TDV6, HSE, 2006
GAP IID BT Tool
2nd Nov 2021 6:50 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4939
Yes, just raise the height control switch and you'll see the system spring into life to meet the demands of the air bags. 1750kpa is the reservoir pressure, once the reservoir valve has closed and exh valve has popped you'll see the gallery pressure fall back to 160 - 200kpa or thereabouts.
I've had another look at your screen shots and the only anomaly I can see is the corner heights which look odd.
Have another look at them whilst raising and lowering the system and post the heights as well as the voltages for each corner height sensor.yµ (idµ - eAµ) ψ=mψ
2nd Nov 2021 7:03 pm
AndreasG
Member Since: 10 Mar 2021
Location: Nicosia
Posts: 92
Managed to take some more readings yesterday Pics posted below.
Again the car was parked on a level surface, in P, engine working and I was sitting in the vehicle. I lower the suspension to access mode and pushed the button to raise it all the way up to off-road mode for the readings. The screenshot was taken after the car reached its full height but the compressor still working (about 40 seconds after pushing the button).
I also calibrated the steering sensor and driving to work today the car felt much smoother BUT I could hear the suspension thudding and clanging throughout the whole drive to work today
I think i'll try it out today again and tomorrow and see how it goes on Saturday when I get it properly aligned.
Live values as below; please let me know if you see anything worrying or that needs attention
Thanks!
Discovery 3, TDV6, HSE, 2006
GAP IID BT Tool
4th Nov 2021 2:08 pm
Yankee_Rover
Member Since: 02 Jun 2021
Location: Seattle
Posts: 183
While you continue investigating the EAS, I’m curious about the changes you made.
What were your old tires? Size and model? Could the harshness be related to a change in tire choice? I notice more bumps in my AT than the OEM Highway tires.
When you replaced the lower control arms, did you replace the entire arm or just bushings? What brand of arm or bushing? Polybush is notorious for a harsher ride, and many complain about them with 19” wheels. Inferior LCAs can appear equal while having slightly altered geometry or bushing material, causing all sorts of other side effects.
If you are hearing clunking / clanking / thumping sounds, particularly from the front. I’d suggest also inspecting other suspension items. Sway bar bushing and sway bar end links would be first suspect. These wouldn’t explain a harsher ride but they would explain sounds. The LCA and tires could explain a harsher ride, but not necessarily the sound (unless the LCA replacement was faulty).
4th Nov 2021 2:55 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4939
AndreasG wrote:
I also calibrated the steering sensor and driving to work today the car felt much smoother BUT I could hear the suspension thudding and clanging throughout the whole drive to work today
I think i'll try it out today again and tomorrow and see how it goes on Saturday when I get it properly aligned.
If you're hearing noises from the suspension there's obviously a component weakness that you or your garage has not spotted. It may be something simple like the anti roll bar links or the bushings. Since you're getting the the geometry adjusted anyway, ask the technician to thoroughly check the entire suspension before he begins.
It's pointless doing the geometry if there is an issue with one of the major components.
The live data from IID will not be able to indicate such an issue, so you need to eliminate the knocking sound before proceeding with the ride problem yµ (idµ - eAµ) ψ=mψ
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