DIY Guide, Rear air spring replacement

[tlow98]

Originally Posted by Abstracted

I didn't experience any danger.

I used a box cutter to slowly cut through the rubber. The cut started a slow leak that I could expand by wiggling it open a bit.

In retrospect, I see no need in using software or taking off body panels and unplug other lines. Manually deflating the bags by cutting them or stabbing them works just fine.

Agree. Just triple check you have the correct part number on the new bags otherwise you’re going nowhere fast.

[Abstracted]

Originally Posted by Mr.47

DO NOT LET THE JACK DOWN WITHOUT REFILLING THE BELLOWS WITH AIR, SUSPENSION DAMAGE WILL OCCUR!

I let the jack down without refilling and as far as I can tell, no damage occurred.

Once finished, I promptly took the beast up to 105mph: No parts came off and I'm still alive

[Autobarn234]

Does anyone know if the air springs are the same for Security Plus models?
I see some aftermarket sellers list the same item for both part numbers 37126795013 (regular F15 X5) and 37126795014 (bulletproof models).

[raducris]

Originally Posted by Maverik259

Also found in ISTA that I had a voltage issue with my driver side rear level sensor. So I bought a new one and fingers crossed it helps with the compressor not filling automatically

Do you remember how that error looked like? Was it happening randomly? Mine sagged for the first time last night while parked inside and, by reading this thread, I have a hard time believing that the culprit is the air spring itself if it sags overnight but then stays up for weeks. At this point in my reading I don't think (yet) this can be a permanent air leak, either form the air bags or the lines, rather the height sensors or the module/software. Valve block would be my last suspect, as, from ISTA diagrams it seems that 2 valves need to open for the air spring to deflate. I don't believe in coincidences, so 2 valves cannot go bad at the same time but one sensor can. I'll keep reading but what is your feedback after 2.5 years, what actually fixed your problem?

[X5guyinRI]

Originally Posted by Sedoy

I recently replaced mine without messing with ISTA. I just unbolted height sensors and set them in high position to make the airbag deflate, after that I disconnected the battery. Super easy to replace, I wish all BMW DIYs were that easy.

I'm trying to do this - super helpful tip. It's not working. I don't hear any noise when I try to move he unbolted height sensor. Do I pull fuse 110 first? Do I need the car on (bot not started)? I've tried everything. I recall you saying if you move it around too much you have to wait. I've tried that too. Not sure what I'm doing wrong. Any help would be greatly appreciated. Car is sitting on jacks and I need to drive 'er tomorrow :-) Thank you! (I do not have ISTA up and operational - but I do have a sharp knife).

[Abstracted]

Originally Posted by X5guyinRI

I'm trying to do this - super helpful tip. It's not working. I don't hear any noise when I try to move he unbolted height sensor. Do I pull fuse 110 first? Do I need the car on (bot not started)? I've tried everything. I recall you saying if you move it around too much you have to wait. I've tried that too. Not sure what I'm doing wrong. Any help would be greatly appreciated. Car is sitting on jacks and I need to drive 'er tomorrow :-) Thank you! (I do not have ISTA up and operational - but I do have a sharp knife).

Manually deflating the bags by cutting them or stabbing them works just fine.

[X5guyinRI]

I did it! Thank you for giving me the confidence to give this a try. What a community. Had to buy a lift and jack stands. For anyone that happens to scroll all the way to page 7 and reads this comment, I'll note a few observations and places where I deviated from the OPs original post.

1. First, the wheels were REALLY hard to get off! I unbolted them easily, but I had to kick, pull and pound the wheels (all while this thing was on jack stands) to get them off. I even googled how to "unstuck" a wheel.

2. I cut the air bag. I completely agree with everyone that said trying to get software to work, or the trick to make the airbags deflate (by adjusting the little arm underneath), or going under the car and removing the panel and pulling the lines, etc. is way too much work. Cutting the bag took seconds. I'm replacing it, I don't care if it's cut.

3. As hacky as this video is, it really helped.

I even bought the wrong jacks, just like he did, and had to go back to the store to get taller ones :-).

4. I found the step to insert the airline back into the new air shock was harder than I expected. It was almost slippery, you had to really grip it hard to force the airline hose into the shock.

5. I found the step to align the air shock top properly into the right place was easier than everyone suggested. I was able to see the pattern from looking up from underneath the car, and align the air shock quickly. It took just a minute.

6. Finally, besides getting the tire off, the hardest part was pushing the two tabs on the bottom of the air shock while simultaneously lifting it up was difficult. I was using screwdrivers, and got it, but it was tricky.

7. I didn't deal with disconnecting the battery, but I did pull the fuse as mentioned in the OPs post. Not sure why you need to mess with the battery - I find that always resets things in weird ways, and I didn't see why I needed to. If I just got lucky by not electrocuting myself, please let me know!

[tventz]

Hi Guys!
Can you do one side at the time? Lift the car on one side, pull the breaker, cut the bag, replace the bag, install the breaker back on, let it inflate and then go to the other side? I assume the car will be standing on three wheels and one will be up and bag worked on. Is right bag connected to the left one? So when I cut one, both deflate? Or they work independently?

Thanks

[X5guyinRI]

Originally Posted by tventz

Hi Guys!
Can you do one side at the time? Lift the car on one side, pull the breaker, cut the bag, replace the bag, install the breaker back on, let it inflate and then go to the other side? I assume the car will be standing on three wheels and one will be up and bag worked on. Is right bag connected to the left one? So when I cut one, both deflate? Or they work independently?

Thanks

Originally Posted by tventz

Hi Guys!
Can you do one side at the time? Lift the car on one side, pull the breaker, cut the bag, replace the bag, install the breaker back on, let it inflate and then go to the other side? I assume the car will be standing on three wheels and one will be up and bag worked on. Is right bag connected to the left one? So when I cut one, both deflate? Or they work independently?

Thanks

Bags are not connected. You can do what you suggested, but why not just lift the vehicle at the center rear mount point, use jacks, and do both?

[Chilled]

So i did mine. Replace with the Arnotts, and am now having an issue where I think its not pumping the bags up enough/holding at level.

Notice a couple of times the compressor running when I park at home. When I am reversing into the garage down a hill. If I park on the hill, engage the hand brake, get out for a sec (with the car running and in park), get back in, park in the garage. When I finish parking, turn off the car, and get out. I will hear the compressor running just as I get out for a split second. This never happened before with the OEM bags.

Has anyone had this issue?

So what is everyone's height with the OEM and the Arnott's bags to the fender. The OEM were at 81cm, and these pump up briefly to 81cm, but end up going down to 78.5cm/79cm.

[acmurda]

Originally Posted by Chilled

So i did mine. Replace with the Arnotts, and am now having an issue where I think its not pumping the bags up enough/holding at level.

Notice a couple of times the compressor running when I park at home. When I am reversing into the garage down a hill. If I park on the hill, engage the hand brake, get out for a sec (with the car running and in park), get back in, park in the garage. When I finish parking, turn off the car, and get out. I will hear the compressor running just as I get out for a split second. This never happened before with the OEM bags.

Has anyone had this issue?

So what is everyone's height with the OEM and the Arnott's bags to the fender. The OEM were at 81cm, and these pump up briefly to 81cm, but end up going down to 78.5cm/79cm.

Arnott bags have the push in fittings and they require decent amount of force to push in all the way ... make sure the air lines are pressed in all the way, most likely the cause of deflation after new bags. Of course now that you have new bags, in order to get them out to inspect those fittings, you'll have to loosen the air lines at the valve block to deflate the system. Not a big deal. Hope that helps

[acmurda]

Originally Posted by Chilled

So i did mine. Replace with the Arnotts, and am now having an issue where I think its not pumping the bags up enough/holding at level.

Notice a couple of times the compressor running when I park at home. When I am reversing into the garage down a hill. If I park on the hill, engage the hand brake, get out for a sec (with the car running and in park), get back in, park in the garage. When I finish parking, turn off the car, and get out. I will hear the compressor running just as I get out for a split second. This never happened before with the OEM bags.

Has anyone had this issue?

So what is everyone's height with the OEM and the Arnott's bags to the fender. The OEM were at 81cm, and these pump up briefly to 81cm, but end up going down to 78.5cm/79cm.

in case a fitting or fittings are defective. Here's the exact ones you can replace them with, any GM dealer should have these. This info was provided by Arnott.

[Chilled]

Originally Posted by acmurda

Arnott bags have the push in fittings and they require decent amount of force to push in all the way ... make sure the air lines are pressed in all the way, most likely the cause of deflation after new bags. Of course now that you have new bags, in order to get them out to inspect those fittings, you'll have to loosen the air lines at the valve block to deflate the system. Not a big deal. Hope that helps

It did take a bit of work to get them in, but they were definitely in as far as they would go. They seem to be holding pressure, just not enough. Had the bags on the car for about a week and they didn't drop. As in just sitting in the garage. So this was the first drive.

It just looks like they are not going/and staying fully up.



Speaking of getting theme out. I saw the Arnott's instructions saying not to unscrew them. So if I do, do I need to replace those fittings as well? As in the fittings on the bag. Or is there a special procedure for that?

Originally Posted by acmurda

in case a fitting or fittings are defective. Here's the exact ones you can replace them with, any GM dealer should have these. This info was provided by Arnott.

That's good to know, cheers. Is this part of a larger instruction manual? Could I grab that.

[acmurda]

Originally Posted by Chilled

It did take a bit of work to get them in, but they were definitely in as far as they would go. They seem to be holding pressure, just not enough. Had the bags on the car for about a week and they didn't drop. As in just sitting in the garage. So this was the first drive.

It just looks like they are not going/and staying fully up.



Speaking of getting theme out. I saw the Arnott's instructions saying not to unscrew them. So if I do, do I need to replace those fittings as well? As in the fittings on the bag. Or is there a special procedure for that?



That's good to know, cheers. Is this part of a larger instruction manual? Could I grab that.

Bags not staying fully inflated is definitely a sign of a leak somewhere in the system.
As for "Arnott's instructions to not remove the fitting"
I called Arnott regarding the same issue when I switched Arnott bags from one X5 to another, according to them that warning is to keep people from over tightening the fittings and damaging the bag itself. After that I was successfully able to remove those fittings from the bags and had no issues re-installing. Just remember not to overtighten. That. image above is what they sent me incase I needed new fittings, its not part of another manual.

[Chilled]

I'll take it is not possible to insert the new fittings into the bags to enable the push in? As in not screw the fitting in with the line, but instead screw the new fitting into the bag and then push in the line. Like they did from new.

Just thinking of replacing the lines, because I undid them at the compressor (to let air out) and maybe the spinning on the fittings caused that side to leak.

So if I am installing new lines, would like minimize the spinning.

[acmurda]

Originally Posted by Chilled

I'll take it is not possible to insert the new fittings into the bags to enable the push in? As in not screw the fitting in with the line, but instead screw the new fitting into the bag and then push in the line. Like they did from new.

Just thinking of replacing the lines, because I undid them at the compressor (to let air out) and maybe the spinning on the fittings caused that side to leak.

So if I am installing new lines, would like minimize the spinning.

Screwing them in with lines pre inserted is not an issue. To keep lines from spinning just hold on to it, there really shouldnt be much drag to make them spin with the fitting. Replacing the lines wouldn't help much I don't think. The lines are one piece and could only leak at the fittings on either the bags or the valve block at the compressor. They're pretty robust otherwise.

[Chilled]

How do you insert the lines without the fitting spinning around the line? Especially on the compressor side, when screwing in the fitting, the line is inside and as the fitting rotates the line cant.

[Chilled]

So just been doing some reading (yep I know should of done this before hand. Stupid me). It looks like i may have messed up the connector install into the compressor housing.

I didn't replace the brass connector/banjo bolts, I just left the ones that were on the pipe there and screwed them back into the compressor.

Also just reading the BMW instructions, and they differ from Arnott's. it looks like the collet/toothed washer is supposed to stay inside the bolt. You insert the whole unit in and then push in the line.


I did order 2x new bolts and they did come with the collet/brass washer already inserted into the bolt.

Will replace the connectors on the compressor side.
Does anyone know the tape they are talking about here?



Also does anyone know what this thing is? its from the instruction on how to replace the lines.

[acmurda]

Originally Posted by Chilled

How do you insert the lines without the fitting spinning around the line? Especially on the compressor side, when screwing in the fitting, the line is inside and as the fitting rotates the line cant.

The line doesn't need to and shouldn't rotate and you don't need to replace the brass collets after loosening a fitting. It's just a simple compression fitting nothing special about it.

[Chilled]

Originally Posted by acmurda

The line doesn't need to and shouldn't rotate and you don't need to replace the brass collets after loosening a fitting. It's just a simple compression fitting nothing special about it.

Was more thinking along the lines of, when unscrewing the brass fitting from the compressor. The fitting must spin, but since the line can't, the fitting spins around it. Maybe this has loosened the seal?

Checked, overnight it dropped to 78.5cm. Will keep an eye on it, now.


Just thinking for the future, if it stays at this level permanently (not going any lower), but not the full 81cm(ish). Would you start at re-doing the fittings on the bags? Or is this bag itself issue.

[Chilled]

So after nearly week of sitting there locked without a battery tender, and it's still at 78.5cm.


Can someone with airbags please measure their ride height, and post how high the fender is and what size rear tire your running.

[tventz]

Originally Posted by Chilled

So after nearly week of sitting there locked without a battery tender, and it's still at 78.5cm.


Can someone with airbags please measure their ride height, and post how high the fender is and what size rear tire your running.

I get 80.0-80.5cm. I have original bags, but they are 4 years old.