E53 2004 Diesel... Saggy on 1 Rear Corner INSTANT FIX

[X5-D-Sport]

Gents / Ladies...and those some where in the middle...

A month or so ago, my Facelift would OCCASIONALLY sag on one corner over night... maybe twice every month...
This hints at a mechanical leak at the control valve block, NOT a leaky joint or air bag or reservoir ...
... because any of these would leak every single day... as opposed to every other week.

I raised the issue here, and by good fortune ended up with a work contract at one of the companies that make/used to make the valve blocks that control the corner levelling for these vehicles....

Whether there is a refurb' kit for the valveblocks I'm unsure - but couldn't find one, only a refurb kit for the main pump..

Now, understanding that this system will have thousands of litres of air pumped thru it over a 100k miles most likely... so is it any wonder that the seals in the valve block may get a tad' dry ??

So, after a good natter with some of the development engineers here at work, I procured a 2cc/ml syringe with a 1inch blunt needle tip full of the specific Silicone Oil that the manufacturers lube these O-Ring seals at point of manufacture.

So, I emptied my boot space,
removed the spare tyre,
Disconnected the battery ++/Red cable,
dismantled the air pump unit to reveal the pump module incl its pipes, wires & other junk as one lump...
Then, One output pipe at a time (Blue & Red) let out some air on each side of the vehicle causing a 3inch sag each side.....
Then, undid the input pipe from the pump.... squirted  the 2cc/ml of Silicone oil into the input.... reconnected the inlet pressure pipe...

Reconnected the battery & the pump kicked in immediately.....
A month later, and the vehicle level has not sagged a single mm since

The company that make millions of O-Rings a month is Superior Seals... easy to find on the Net...
However 500cc of this Silicone Seal Oil is approx. £195 + vat + freight...

Noting the Silicone Oil for these seals is very specific in its ingredients so as not to corrode other materials in the vehicle, ie pressure sensor electronics, the seals them selves, aluminium parts, the air bags, None Hydroscopic etc... (you cannot squirt any old crud into this air system- Take Note)

I will try to find a cheaper source of this goo with the correct inhibitors if any of our members are interested....
Silicone + correct syringe (with safe BLUNT tips/needles) ...AT COST + £2 to post... I'm guessing approx. £7 all incl.... interested ?

Personally the options of .........£200 new, or £85 for a second hand valve block that could fail soon,
or £7 spent on some goo & 15 minutes tinkering seems a better option to me.....

Penny for your thoughts...

[Dave ett]

Very interesting - good skills!
I have a slightly saggy left corner so would be up for some goo.


Sent from my iPhone using Tapatalk

[Denis O]

Disconnect the red cable.

No, no and thrice no.

Disconnect black cable first.

[MrMaloo]

I dont drive my x every day but when i go to use it i've noticed it sits very low until started....then it gradually rises to correct height. Should it be 'relaxing' in this way between drives? Or do i need the syringe kit? Mine is a 4.8is so has the all setup all round.

Thanks

Jon

[X5-D-Sport]

Okie gents...

Let me make what I did a little clearer, as it was written in a rush earlier...
On My own vehicle... which only has air bags at the rear...
I disconnected the battery 1st..... this prevents the pump operating when the vehicle senses its not level...
Then I released one of the pipes from the OUTPUT of the valve module that went to left or right, allowed some air out until it visibly allowed a corner to sink....
Then did the same for the other corner...
Do this one corner at a time & reconnect the pipe before you move on to the next corner pipe air feed...
NOTE WELL that these pipe release connectors are often plastic and VERY FRAGILE.
If they are unscrewed, they only need nipping up very gently... be gentle...

Then, i disconnected the single main air input pipe to the valve module and fed  about 1-2cc of this silicone oil into the PIPE...
Then reconnected this pipe back to the pump....
Re- assembled the pump into its housing...
And re-connected the battery.... the pump began operating soon after... cannot remember if it was when I turned the keys or on battery connection....

When reconnecting the battery... MAKE SURE you dont short the battery with any of the iron-work brackets that hold the pump housing in place... or your world will change for the worse... instantly...

Richard who write here is very knowledgeable on this and every other X5 topic and may be best able to advise whether this procedure will possibly solve your particular problem concerns....
but one thing seems likely to narrow down the cause of the suspension sags...

The Silicone Oils remedy may or may not work for you of your vehicle sags every day...
If it does not work for you, then you will more likely have a leak in the reservoir, or the air bag or the pipes to either of these...
At least you can rule out the valve module... and look further down the line...

If you vehicle sags once in a while, then the reservoir and bag are likely ok... or your vehicle would sag every day...
Therefore more likely leaky seals on the valve module... or leaky pipe connectors.

If you two guys above this posting want to PM me contact details i will gladly post you both a syringe of this stuff and you can pop the results back on this topic column.

Regards
Grant B