E53 rear air suspension problem

[eckbmw]

Hi
Normally when I open the car using the remote the rear suspension pumps up and you can indeed hear the compressor running.
The last few days this has not happened and the rear arches sit just above the top of the tyres on both sides.
I connect INPA to the car and pump up the suspension successfully and the car stays this way all day whether I run around in it or it's parked for hours.
Next morning though there it is siti-tng down at back again.
I have no error codes in INPA and obviously the compressor functions.
Can anyone help.

[Horizon]

It's obviously loosing air from somewhere. I can't ever recall my compressor running when I had my E53 in 2 years.
It defiantly shouldn't loose enough air over 24 hours to make it sit low.
Either leaking air bags, try using a spray bottle with water and fairy liquid to spray on the air suspension bags to check for leaks.
If the bags are ok, it could be the valve block that controls the inflation/ deflation of the bags. If the seals are gone it will allow air to weap out and deflate the bags overnight.
Use the search button to find relevant previous posts.
Some one fitted one off eBay from a disco, as they are the same I think

[X5-D-Sport]

If the Valve block is acting up, understand that the air it draws thru it is the unfiltered dusty filth that sits in the tyre well... the same dusty air that gets stirred up with every pot-hole & bump..

This eventually dries out the seal "O" rings in the valve block & can cause leakage by-pass.

Very often, the valve block can be given a new lease of life by using some spray silicone by giving lots of good squirts into the air input side of the valve block, or even by removing the intake filter at the pump & giving good squirts into that as the pump is running, the pump is a one way valve & cannot hydraulically lock - so you can squirt like hell into the intake as she pumps & thus lubricates the valve block.

In industrial applications of similar Valve blocks, that often pass MUCH LESS air, they have an oil droplet feeder & a decent intake filter too.... our expensive cars have none of this, so some lubrication is definitely worth a go.

NOTE WELL... the couplings to/from the pump / valve block etc are soft as butter & VERY brittle... finger tightness only on small spanners - NO pliers or grips.

[eckbmw]

[quote="X5-D-Sport Salisbury"]
If the Valve block is acting up, understand that the air it draws thru it is the unfiltered dusty filth that sits in the tyre well... the same dusty air that gets stirred up with every pot-hole & bump..

This eventually dries out the seal "O" rings in the valve block & can cause leakage by-pass.

Very often, the valve block can be given a new lease of life by using some spray silicone by giving lots of good squirts into the air input side of the valve block, or even by removing the intake filter at the pump & giving good squirts into that as the pump is running, the pump is a one way valve & cannot hydraulically lock - so you can squirt like hell into the intake as she pumps & thus lubricates the valve block.

In industrial applications of similar Valve blocks, that often pass MUCH LESS air, they have an oil droplet feeder & a decent intake filter too.... our expensive cars have none of this, so some lubrication is definitely worth a go.

NOTE WELL... the couplings to/from the pump / valve block etc are soft as butter & VERY brittle... finger tightness only on small spanners - NO pliers or grips.
[/quote]What you say makes a lot of sense and this is a route I will go down when the weather clears up (It has been raining cats and dogs for the last few days here). The usual suspects such as pneumatic springs would seem unlikely as it would be strange for both sides to suddenly fail. I suspect any leak I have is extremely slow and may be down to what you describe. I happen to have a supply of silicon lubricant so will give it a go.

[X5-D-Sport]

Yeah, the giveaway that a Block seal is playing up - that the whole rear goes down.

I will be VERY surprised if the Silicone does not fix the issue, as I've fixed 6 vehicles now with the same issue.
My own vehicle sank on one corner... & 2 years on it's still fine.

If the pump raises the suspension when you open up, unplug the connector power at the pump & loosen the pipe unions a few turn in the Front-Right of the boot floor to allow the rear end to sink as low as you dare...

Then remove the union pipe feed from the pump to the Block AT THE BLOCK.
BIG squirt of silicone in the block, re connect (gently) & power up a few seconds, remove the pipe to the block again - several times & pump a bit more after more silicone....

Then allow her to pump up properly to normal ride height, & this will probably solve the issue for keeps.
Regards
Grant B

[henrym3]

Sounds like a good preventive maintenance tip when your in there for whatever reason.

[X5-D-Sport]

Agreed,
A pump unit or Valve block is potentially a hugely expensive item.

My rear suspension pump AND Valve Block have acted up in the past... and some silicone lubricant fixed both.

For the sake of a can of spray silicone, it is a good action for prevention better than cure me thinks....

[chrisn7]

When you say silicone lubricant, what exactly is the product please?

[Alan Gunn]

This is the one i use a lot.
https://www.amazon.co.uk/WD-40-Speciali ... cone+spray

[X5-D-Sport]

Hi Alan,

YES, that will work just fine.

Silicone Dash-Board cleaner is NO GOOD, but a Purely Silicone Lubricant is ideal.

The variant the manufacturers use on the "O" Rings when new is a much higher grade, as it goes further, but the link above will be quite adequate for this.

A damned good squirt into the Pump intake hole is worth doing too, as it will rejuvenate the pump's piston ring & clean out & better seal the valve on the cylinder head of the pump too.

[centurion]

I have a similar problem albeit my pump does not react at all and i do not even have a LED light anymore next to the steering wheel (up/down suspension). And the most weird thing is that using DIS i can control the height!? Any suggestions?

Ps. No errors on the dis or inpa.


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[centurion]

One other thing, can anyone point me to how to take out and check air line from the pump? Connectors seem a bit fiddly and i'd like to know how could i disconnect the air line?

Thx


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[eckbmw]

Apologies for the reply in responding as I didn't want to jump the gun and assume everything was OK. I set out to carry out the silicon spray job as recommended by "X5-D-Sport Salisbury" and carried out the initial removal of pump / compressor unit. Had a little look just to suss out what he was describing. I didn't actually remove anything other than the block connector that is situated by the right hand side accumulator (As observed from rear of car) as it was my intention to nip up to Halfords who keep silicon spray in stock. Anyhow as usual the rain came on big style again and I sat in the drivers seat with the intention of closing down INPA when I noticed the option to close hand control which I did. Due to inclement weather work was cancelled for the day.
Now 3 days later each morning my car has lifted as it should when key fob pressed to open car. Was it the fact that I chose the "close hand control in INPA" or the fiddling about with block connector which may have not been seating properly. Perhaps I'll never know but as you can all understand I am mightily relieved.

[centurion]

Hi, could you post a screen shot of what you did in INPA? Thx


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