EAS: Diaphragm question

NikTheGeek · Apr 26, 2013

Attached is a pic of both sides of the diaphragm I fitted that didn't work. I had to put the old one back in. But I still have a slight leak so I want to have another go.

Clearly it goes white/aluminium side down, facing the spring. But how does it work? There's no hole in it to let air pass so what is its function?

Also, ebay member Symlisep38parts (who I didn't get it off) says: "Lubrication and the metal insert from the old diaphragm are essential for correct function" I assume I don't need the old metal bit as I have a new one, but what lubrication? I didn't lubricate it. But then the old one that came out wasn't lubricated - it was softer rubber tho...

tnx

Nik

wammers · Apr 27, 2013

If you look into where is sits you will see a brass port about 9mm across. This is the outlet from the filling/exhaust gallery. When compressor is running the diaphragm solenoid opens and puts air pressure under the diaphragm pushing it up to seal this outlet. When compressor stops the air is exhausted through the 4mm pipe into harness. Allowing the residual H/P air used to fill the tank to exhaust to atmosphere. Only then can air be exhausted from the bags. Is it leaking with compressor running or with compressor stopped? If still leaking when compressor has been stopped for a while look at my "How to" and follow the guide to discern what is leaking. Diaphragm should not need any lubrication.

NikTheGeek · Apr 27, 2013

Thanks. I'm not sure to be honest. Now all seals are done, the compressor runs when the car is first started then stops and only runs occasionally. The car jumps up when you raise it in a second or two. It maintains it's height over night and doesn't drop on any corner. However, after driving it it has dropped a bit and unless you allow it to come back up before turning the engine off, its in access mode and will have to come back up next time its started.

The only seal I haven't replaced is the diaphragm because when I tried, it wouldn't fill or raise at all.

I have measured heights all round and they are 48cm from wheel centre to wheel arch in standard height. But I haven't checked or carried out calibration.

I wonder if calibration is out a bit between wheels and driving it is causing it to try and self level. It didn't help that air lines 3 and 4 were swapped around before I refurbed it...

Nik

Datatek · Apr 27, 2013

I don't like the look of that diaphragm, never seen one quite like that.

NikTheGeek · Apr 27, 2013

Datatek said:
I don't like the look of that diaphragm, never seen one quite like that.

Well it didn't work!!

Datatek · Apr 27, 2013

NikTheGeek said:
Well it didn't work!!

It just looks too thick and rigid from the photo. Was it from the Dutch site? If so it's crap.

NikTheGeek · Apr 27, 2013

Datatek said:
It just looks too thick and rigid from the photo. Was it from the Dutch site? If so it's crap.

No, a UK ebay seller. Not Symlise. However, looking at his:
RANGE ROVER P38 AIR SUSPENSION VALVE BLOCK DIAPHRAGM | eBay
I wonder if I should remove the white bit and re-use the bit that comes off the old one as he says "the metal insert from the old diaphragm is essential". So I might try that. But yes, the rubber was a lot thicker. Maybe I should just buy his

Nik

Datatek · Apr 27, 2013

NikTheGeek said:
No, a UK ebay seller. Not Symlise. However, looking at his:
RANGE ROVER P38 AIR SUSPENSION VALVE BLOCK DIAPHRAGM | eBay
I wonder if I should remove the white bit and re-use the bit that comes off the old one as he says "the metal insert from the old diaphragm is essential". So I might try that. But yes, the rubber was a lot thicker. Maybe I should just buy his

Nik

Get a proper one from Symlise

NikTheGeek · Apr 27, 2013

Datatek said:
Get a proper one from Symlise

Just ordered one of his!

wammers · Apr 27, 2013

NikTheGeek said:
Thanks. I'm not sure to be honest. Now all seals are done, the compressor runs when the car is first started then stops and only runs occasionally. The car jumps up when you raise it in a second or two. It maintains it's height over night and doesn't drop on any corner. However, after driving it it has dropped a bit and unless you allow it to come back up before turning the engine off, its in access mode and will have to come back up next time its started.

The only seal I haven't replaced is the diaphragm because when I tried, it wouldn't fill or raise at all.

I have measured heights all round and they are 48cm from wheel centre to wheel arch in standard height. But I haven't checked or carried out calibration.

I wonder if calibration is out a bit between wheels and driving it is causing it to try and self level. It didn't help that air lines 3 and 4 were swapped around before I refurbed it...

Nik

The diaphragm valve CANNOT cause the suspension to drop. It is only ever used when the compressor is running. As explained earlier. The Dutch ones are to stiff.

EAS: Diaphragm question

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