4 Corner suspension - rear left low

Paulpen · Post by **Paulpen** » Wed Jul 13, 2016 6:49 pm

Hi guys - thought id start trying to sort all my issues out and suspesnion is first on the list.

The rear left corner is / was low. Would go up and down but always be too low. It looked to have a new level sensor on that corner too.

The compressor cuts in as it should and creates 15 bar pressure and there are no signs of air leaks.

The ride height voltages were all over the place so recalibrated them with the snapon scanner and now have a bit more of a level vehicle !

It will do normal height and raised height pretty much as it should howver it never gets to fully low - it gets most of the way and the low position just keeps flashing.

The sensor voltages and deviations look to be pretty equal but ive got a few questions !

When raising the suspension all the voltages seem to go up apart from the front left which seems to go down - is this normal ?

Also when calibrating the height the scanner asks is it has sport or comfort suspension and if its on a standard or modified bmw chassis - how do I know the correct answer for these questions ?

Finally when entering the heights I want measuring from the bottom of the wheel rim to the bottom odge of the wheel arch - is this correct ?

Many thanks

Paulpen · Post by **Paulpen** » Thu Jul 14, 2016 10:08 pm

Heights all calibrated many times and still proving troublesome !
It will do standard height and offraod height fine. Putting it to access height will result in it lowering but the low position light will just keep flashing.

Drive it around for a bit in normal height and the tyre pressue light and suspension inactive warnings will come on.

Igntion off and on and then read the codes - a pair of codes in the ABS ECU (5F1E variant code) and (5DD7 height invalid).

Data list shows that the front left deviation from satndard value is 1800mm !

Reset and calibrate all the ride heights again and all back to the start until the fault pops up again on driving !

Is there a standard spring conversion for all round air setups....

Horizon · Post by **Horizon** » Thu Jul 14, 2016 10:56 pm

There is a £200 rear Spring conversion for the rear, available from eBay, or SE spec springs and cups from the dealers.
But the front needs coil overs , Raj did a coilover conversion on his 4.8 a few years back, there is a few post if you do a search. It's the Achilles heal of the 4.8 the all round suspension.
Coilover so are the way to go, all round .

http://xdrivers.co.uk/forum/index.php/t ... #msg135676

Paulpen · Post by **Paulpen** » Thu Jul 14, 2016 11:28 pm

Ive literally just been reading that and messaged Raj about it !

Id be curious on how comfy the ride is compared to the air and also how it would perform if towing ?

As much as I want to get my air working I dont want to keep throwing money at sensors and modules that may fail again if there is a solution that does not require as much maintanance and fits my needs

Mpower · Post by **Mpower** » Fri Jul 15, 2016 8:40 am

I've done the same conversion on the 4.8 and tbh it isnt that difficult,its labour intensive espcially the fitting of the rear springs but very achievable.
Get it done and you wont have any more issues after!

Regards to ride quality its not far off from all round air but its no big deal.

Mpower

Paulpen · Post by **Paulpen** » Fri Jul 15, 2016 6:47 pm

The labour is not an issue for me tbh - its the ride and the fact I might be towing thats my main concern.

Where abouts are you based chap ?

Mpower · Post by **Mpower** » Fri Jul 15, 2016 8:46 pm

In Hertfordshire & yourself?

Paulpen · Post by **Paulpen** » Fri Jul 15, 2016 10:07 pm

Somerset - not like I can pop over for a lookie :'(

Mpower · Post by **Mpower** » Sat Jul 16, 2016 7:38 am

It wasnt my car just helped a mate out who had the same problems as you are constantly pouring money replacing parts like as if a bottomless pit.
That was 2years now and he's not spent any more £'s on it and the ride is good so no negatives.

Regards to towing I believe at the time I fitted the rear springs you can get the updated ones for towing haven't looked since.

Mpower

Here you go mate if you read further down the descriptions you will find the updated springs for towing.

http://www.ebay.co.uk/itm/BMW-X5-REAR-SUSPENSION-AIR-BAG-TO-COIL-SPRING-CONVERSION-KIT-1999-2006-E53-/251990393553

Paulpen · Post by **Paulpen** » Sat Jul 16, 2016 7:44 am

So you can mix towing springs on the rear and coilovers on the front ?

And then just code the air suspension out ?

Mpower · Post by **Mpower** » Sat Jul 16, 2016 8:21 am

Yes Paulpen that's the best option,coding out is easy if you use Ncexpert which I used to remove susp. Inact from cluster,after a full 4 wheel alignment to sort the geometry.

Paulpen · Post by **Paulpen** » Sun Jul 17, 2016 2:00 pm

Handy to know it can be done in a neat fashion then if the worst does come.

Im determind to get it sorted though !

Paulpen · Post by **Paulpen** » Mon Jul 18, 2016 10:11 pm

Hi guys - think I cracked it tonight !

Checked the sensor positions as advised and all looked correct.

Checked that battery too and showing over 13.4 at the module and just under 14v at the battery so a slight drop down the length of the car. No resistance over the earth side to body at all.

Recalibrated again tonight and still no luck - the back end never want to sit at the correct height anymore. Found a damaged pin on the module connector (pin 8 to the front axle solenoid valve) so repaired that. I suspect someone has either front probed it and damaged it trying to diagnose this or a previous issue as it was in a right state !.
Recalibrated again and no luck with back end again. When moving the vehicle through all heights and while driving all the sensor voltages are showing as correct and moving however only on of the deviations out of the four actually varies when driving !. I think the module can see the inputs correctly but cannot seem to calculate what they mean or cannot store the calibrated settings - maybe due to the damaged pin or maybe just a dead module.

Module on the way - jus need to find out how to code it myself now !

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