gareth71
Member Since: 10 Apr 2016
Location: North-east Wales
Posts: 568
  
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| Suspension dropping slowly - likely causes? |
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Last few days, have noticed that the suspension on all four corners (but more noticeable on the front) has been dropping very slowly when parked up.
Did some measurements - ran the compressor to the point of cut-off yesterday afternoon, and set standard suspension height. 27 hours later, and it's lost 20-25mm of height on both front corners, and 7-10mm of height on both rear corners.
Possibly related, possibly not, but has been happening for quite some time - compressor runs for quite a long time when starting after a period of being parked up just to get the reservoir back up to pressure, so to me that suggests gradual loss of pressure in the system.
Reservoir tank, relief valve and compressor were replaced two years ago.
Thoughts?
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 24th May 2024 9:18 pm |
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Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10414
 
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Seals in the front valve block probably want replacing.
Seal kits on eBay
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| 25th May 2024 7:57 am |
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desv8
Member Since: 01 May 2020
Location: CHELTENHAM
Posts: 126
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Mine ended up being a small leak on the front OS strut.
Suspension in off road, plenty of soapy water and eventually found a small leak. Struts were original from 05 and over 200k so let her off.
Good luck.
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| 27th May 2024 10:06 am |
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gareth71
Member Since: 10 Apr 2016
Location: North-east Wales
Posts: 568
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D3 went in for a service and MOT this week - asked them to have a look over the air susp system, mentioning the significant height drop over the course of a weekend (ended up dropping about 40mm front and 30mm rear over three days) - "no leaks found". Well, that's clearly wrong!
The fact that it's dropping evenly, and not just one corner, suggests valve block issues, I guess. The drop on all four corners rather than just two - would that point to the centre block by the compressor?
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| 30th May 2024 1:34 pm |
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Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10414
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The car electronics self levels when parked.
Ppl remove a 20a fuse under the bonnet to stop this, for diagnostics
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| 30th May 2024 3:08 pm |
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gareth71
Member Since: 10 Apr 2016
Location: North-east Wales
Posts: 568
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That's the next plan! Won't need to drive it anywhere over the weekend, so going to pull the fuse and leave it for a couple of days, see if the drop changes from all four corners to just one or two.
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| 30th May 2024 4:11 pm |
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AdamB
Member Since: 18 Jan 2023
Location: Thurrock
Posts: 114
 
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Pulling the fuse is the best starting point, it will self level otherwise and hide the source of the issue. Even overnight or if it's left parked for a period at work or whatever is worth doing. It should show itself quickly once isolated.
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| 30th May 2024 4:31 pm |
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gareth71
Member Since: 10 Apr 2016
Location: North-east Wales
Posts: 568
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Fuse 26 in the engine bay fuse box, right??
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| 30th May 2024 5:30 pm |
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gareth71
Member Since: 10 Apr 2016
Location: North-east Wales
Posts: 568
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Right, after a couple of days with fuse 26 out - OSF dropped by about 60mm, NSF by about 30mm. NSR lifted up by about 15mm (to be expected, given the big drop on OSF), and OSR dropped by the same amount (makes sense, same amount of air in the rear system, balances out).
Gave the OSF air bag a quick spray with soapy water this evening, no obvious leaks (was getting a bit dark by then, will give it a proper look tomorrow or Tuesday) - but assuming air bags are fine I guess it's front valve block.
Any good videos with a how-to in terms of getting at it? Seems easy enough once I'm in there (seal refurb kit from eBay), but does the wheel arch liner need to come out or is there a better way of accessing it?
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| 2nd Jun 2024 10:54 pm |
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Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10414
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You could remove the bumper, if it’s been off recently
Most ppl go in through wheel arch.
When you loosen the pipes the front suspension will drop. So axel stands or deflate first
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| 3rd Jun 2024 7:43 am |
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gareth71
Member Since: 10 Apr 2016
Location: North-east Wales
Posts: 568
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Useful write-up, thanks. I guess just removing enough fasteners to pull back the front part of the wheel arch liner would be enough - no need to remove the whole things.
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| 3rd Jun 2024 11:21 am |
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gareth71
Member Since: 10 Apr 2016
Location: North-east Wales
Posts: 568
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Just for the hell of it, I popped the fuse back in, lifted the D3 to offroad height, then pulled the fuse again. Interestingly, it's dropping much less this time around.
Last Friday evening the offside front was at 815mm (standard height) to the wheelarch, and by Sunday evening it was down to 755mm. Fuse in, lift, fuse out... OSF at 859mm (offroad height), and just now, three days later, it's only dropped to 825mm.
The other wheels have followed the same sort of trend as last time - NSR has 'cocked its leg up' a bit to compensate for the OSF drop, and the other two have only lost about 10mm each.
So 60mm drop on OSF in 48hrs from standard height - but only 30mm drop in 72 hrs from offroad height.
Might be significant, might not - thoughts? Am I overthinking this?!
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| 5th Jun 2024 9:03 pm |
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Trickysummer
Member Since: 23 May 2016
Location: Maidenhead
Posts: 16
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I had similar problems a few years back on my ‘12 disco. After months of trialling fuses etc my compressor finally burned out as it was working hard to keep things level. I changed the front valve block and that fixed the issue. No probs since, but I wished I fixed it sooner as the compressor was an expensive casualty. The valve block is a pretty easy diy job & maybe worth trying, if I recall the part is around £50?
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| 5th Jun 2024 10:38 pm |
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Pete K
Member Since: 15 Jan 2016
Location: GL
Posts: 10414
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Yeah. The front value block is easy to access and a common issue. So worth doing anyway as maintenance
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| 6th Jun 2024 8:14 am |
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