How to Remove and Replace the Air Suspension Strut on Your Discovery 3, 4, and Range Rover Sport

Hello and welcome to The Britpart Workshop. I'm here with Paul Myers, Britpart MD. Paul, tell us when you want to ensure Britpart quality, how do you make that happen? Okay, we have 800 customers worldwide who stock our parts and distribute them. We list those on our website, but basically any of the major Land Rover repair shops in the UK, in Europe or the rest of the world, will be able to source our parts. Great, because they're all trade customers. Aren't they? Absolutely. We are a trade wholesaler so we supply for the trade. Great. But you're all branded in those workshops. So if you want a Britpart part you can go there and specify. Absolutely. Great stuff. Okay, so what are we looking at today? Okay. This is air suspension unit of a Discovery 4, very similar technically to Discovery 3 and also to Range Rover Sport. The air suspension replaces traditionally a coil spring by having an air bellow and that's the main cause of failure. So what, the bellow just in here, is that right? This is the air bellow in here. Yeah. After use, it will start to leak air and the suspension on the car will not hold its correct ride height anymore. Right and that's how you diagnose it, I imagine. Absolutely, yes. It can either completely burst and fail which is quite obvious all overnight, it will start to gradually sink the car. And in the morning, you'll have a car sat too low. Okay, and this is OE spec stuff, is it? Absolutely, this is exactly the same as was put in the car when it was originally built. Great, okay. Well look, we're going to go over to the workshop now where Steve and Martin are going to fit one of these and they're also going to explain some of the important safety aspects of replacing suspension components, such as this as well. Let's go and see what they're up to. Right, so we've got the old strut out. That's held in place by a long 24 mil bolt through the lower wishbone. Once that bolt's out, all the pressure is released from the strut itself. You've then got three 15 mil nuts on top which go on to studs on the top plate. Once they're removed, the strut can be lowered down a couple of inches to give access to a 12 mil brass air fitting on top. Undo that. As you loosen it, it's perfectly normal to hear some air escaping because the system's never fully depressurized. Even if you're in access mode or you've gone into it with a diagnostic computer. So once you've released the air pipe, the old unit can be lifted away. It's then important that you remove the old brass fitting from the pipe because that will just push straight into the top of the new component, which Steve is now going to fit. So he's just slotting the lower bush into the wishbone now and then he'll offer up the top plate into the bracket on the chassis. Just hear the threads passing through there. And then it will start the three 15 millimeter nuts on the top. We've got a pillar jack just placed under the wishbone there. That's just to add a little bit of support and to make lining up the lower bolt with the holes on the wishbone a little bit easier. It's a little bit fiddly to access the 15 mil nuts. So generally, the flexible headed ratchet with a shallow socket or a 15 millimeter ratchet spanner is the best tool for this job because there's not a lot of clearance between the inner wheel arch and the top of the chassis bracket. You see, he's just jacking up the lower wishbone now to align the hole in the bottom of the strut bush with the hole in the wishbone and the lower bolt can then be slipped through from the front. Once that's through, the washer and the nut are just loosely fitted. And the next job is tighten up the three 50 mil nuts on the top of the strut plate, that will bring it up into the bracket on the chassis and hold it securely which makes fitting the air parts a lot easier. Just a smear of grease or something on the threads makes running the nuts down a lot easier on this. You'll find that when unbolting the old one if there's any rust or dirt on the threads, it can be a pain to get the nuts undone. Because the rim, those nuts are tucked right over the back of the strut. Steve's just using a ratchet, a long-handled flexible headed ratchet with a 15 mil socket just to speed things up a little bit. Once those three nuts are tight, the last job at the top end is just push the air pipe into the brass fitting. And the way you can make sure that that's fully located is to just give it a little pull, make sure it's not going to come out. Just going to use some long nose pliers to make sure it is fully home. Once he's happy that the top end is all complete, the last thing to do is to nip up the nut on the lower bolt but not fully tighten it yet. And the reason for that Fuzz is going to explain now. When fitting suspension components, it's vital that you did not tighten them fully until the weight of the vehicle is on them. So down off jacks or off ramps, the weight of the vehicle sitting down on suspension, then nip it up. And there you go. It's tight and in the correct position, which means that the component itself is working within its limits of operation. That's what we want. However, if we tighten it before putting the weight of the vehicle on, then we will be forcing this rubber bush into a sheer motion which is beyond its normal limits of operation. So even before the component's down where it should be there's loads and loads of tension in that bush and that's going to be far too much. The suspension isn't going to be operating right. And that bush will fail pretty quickly. So loosen it off, get it with the weight on, right height. That's perfect. Nip it up. There we are, working exactly as it should do. No stress. Right, so we've topped up the lowest strap bolt at ride height. We've put the wheel back on. The final thing to do is to start the engine, make sure the suspension cycles through all its heights and listen for any leaks. Start her up, Steve. That all seems to be working properly. For more handy tips on how to work on your Land Rover, check out the rest of the Britpart Workshop video series.