Thread: Changing the air struts in a Discovery 3

I've been merrily tinkering away with my 2007 Discovery 3 TDV6 for the last 12 or so months, doing various maintenance bits and pieces to get her up to scratch. One of the things I've been working on is the ride quality, which, while not terrible, wasn't as good as I thought it should be.

The primary symptoms I've been looking to rectify have been a harsh ride over rough terrain (even mild stuff like poorly patched bitumen), excessive bounce and body roll and tram lining.

To date, I've replaced the front and rear ARB bushes and front lower control arms. They certainly improved my symptoms but didn't resolve them, so after a bit more research, I decided to replace the air struts. I've not got any leaking from the bags, but I suspect after 11+ years, the shock absorbers are a little second hand.

My first task was to find a supplier. Prices for the struts vary wildly: $550-700ea from local suppliers for non-genuine OE-spec replacements, around $900ea for genuine Land Rover parts and between $260-400 for UK-sourced aftermarket parts (plus shipping).

I wound up purchasing from Island 4x4 and asked them beforehand about their supplier, as it wasn't clearly indicated on the product pages. This is what they said in response to my query:

No they won’t have any branding. They are made by BWI who make them for Land Rover (BWI own Delphi)

Good enough for me to take a punt! I bought two Discovery 4 front struts (LR032646) (based on stuff I'd read which indicated the D4 had nicer damping) and two Discovery 3 rear struts (LR038096) (based on the fact that they seem to be the same). Delivered for $AUD1410.

Install day came around and I inspected the new struts. Here are the fronts sitting on my work bench:

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You'll notice they have no branding on them, unlike genuine or Dunlop aftermarkets (see Island 4x4's comment above). They look clean and shiny and about the right shape, so I proceeded.

I first jacked the car up and installed stands under the chassis rails to do the front. Once the car was up, I plugged in the IIDTool and deflated the struts (Service Test -> Suspension -> Deflate Corners). With the wheel off, the first job is to remove the bolt securing the shocker to the lower control arm. Note that this bolt is supposed to be torqued to 300nm, so it'll be tight! Depending on the condition of that bolt, you might need to get some penetrating oil onto it.

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With the bottom bolt removed, the next task is to remove the three bolts at the top of the strut. Access is tight (you can just fit your hand in there), but it's only the rearmost of the three that is a real pain.

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At this stage, leave the air line attached (you'll remove it once you've loosened the strut). This photo was taken after I installed the new strut – take note of that little bracket above the nearest nut: that's meant to sit under the bolt. The bracket is a bit loose and a bit fiddly (seems like a poor design, really), but there you go. With the three bolts removed, the strut will drop and you can get easier access to the air line. The brass fitting there is undone from the strut and you then remove and discard the brass fitting, leaving a bare plastic pipe.

Old versus new struts, front and rear below. The rear had a torn gaiter that I was going to replace, but decided to just do the whole strut. The struts are stamped with 03/2007, so they've done a solid decade's worth of work!

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Refitting is more or less the reverse of removal. The manual says to tighten the three bolts on top of the strut to 63nm, but I'll be buggered if I can get a torque wrench in there. I put some loctite on the bolts and did it up to be "pretty tight", using feel at removal time as a guide. With the top three bolts in place, you reach in to the air line and push it down into the new brass fitting on top of the strut. It's correctly seated if it doesn't pull out with a light tug.

I used my trolley jack to raise the hub assembly to the right height to slide the bottom bolt through the lower control arm and strut. Loosely do up the bolt, then raise the hub assembly so that the distance between the centre of the hub and the top of the wheel arch is 465mm (485mm for the rear) – normal ride height. Now torque that bolt to 300nm. This ensures there aren't unnecessary shearing forces applied to the bush when the bolt is tightened/returned to normal ride height.

Replace the wheels, lower the car, torque the wheel nuts. Start the engine and re-enable the EAS in the IIDTool. The bags should reinflate in about 30-60 seconds. I ran through the height calibration procedure for good measure too.

With the struts replaced, I have noticed a marked improvement in ride quality. It's still like driving an armchair in comparison to my wife's Evoque, but that's what you get with a Discovery. The main test for me – driving over those bumps and uneven surfaces – is passed with flying colours. I'm really, really happy with the result and fairly certain I've saved myself a small fortune doing the job myself.

I reckon the two best resources for doing this job are the Haynes Owners Workshop Manual and this great clip from Britpart. It's an easy job for the average joe to have a crack at in the driveway. You really only need a jack and stands, a torque wrench and socket set and (to make your life easier with those top bolts) a set of ratcheting spanners. Having never done it before, it took me about an hour per corner. I reckon it'd go a lot quicker next time around.

I reckon I'll tear down one of the struts and have a look at replacing the shock, as that's the other option you could look at if the bags are OK. I'm interested to see what kind of aftermarket shock absorber might be coerced into the strut. Bit of a labour intensive exercise, but a bit of fun if you're into that kind of thing. One of those shed projects I'll probably never get to!

Hope this is of some use to people.

Cheers,

- Andrew

So, managed to get my 4 struts replaced on Saturday. Make such a difference having a hoist - I think it halved the time we would've taken otherwise!!!

Thanks Andrew for the great tips (along with the youtube clip and pointers from a couple of other posts). Similarly, took about 4-5hrs all up - with the front right being the hardest (small hand clearance, top rear bolt being the hardest to access).
All the tool tips around having ratchet ring spanners etc were useful. Not essential, but make it easier.

The small bracket on the 2 front struts looked like it was just there to hold the engine heat-shielding in place. As you said, not a great design, and easy to miss (leave loose) if you're not looking for it.

Great job to have done (and now have 4 used-but-functional spares!)...

Surprisingly, I don't notice a substantial improvement in the ride (even though the old ones had done 225k kms!!! Still an awesome ride!

Thanks for your help.

Rob