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AdamB

Touring rear suspension dropping whilst parked

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I’ve noticed the rear suspension drops whilst the car is parked. It’s not immediate, normally takes a couple of days.

 

it drops substantially more on the o/s.

 

as far as I’m aware, the bags were replaced a few years ago.

 

don’t get me wrong, it looks pretty cool slammed over the M Para’s, but I’m not sure if it’s right.

 

id assume a certain amount of droop after a while is normal?

 

it still pumps up happily when the engine is started.

 

Are my bags bad, is there anything else to check?

C1D53E7B-95C0-4773-8B36-FC61BD1B891A.jpeg

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Shouldn't be dropping at all

 

You've either got a small leak on the bag; a leak on the connection or issues with the compressor. The sensor needs checking too as if that's failing/failed or the arms snapped, that'll cause issues too. These need to be replaced with OEM sensors and not aftermarket

 

It all needs to be checked out and see what's going on

 

FYI folk use cheap bags and they're cheap for a reason. Personally I wouldn't use anything else but the Arnott bags

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I’ll see how bad it gets. I’ll try and grab some leak detector spray the next time I’m in work.

 

I turned car on yesterday and it’s still ok, a little down, but not fully. At least it’s not gushing out.

 

I’ll factor it in when I get the sills/rear end tidied if it becomes an issue.

 

still not sure if I want coilovers all round, or just at the front. I’ve got bilsteins all round at the moment that seem quite stiff, as expected, but it doesn’t seem to sit quite low enough for my liking.

- I know bags can be adjusted to suit the front if necessary.

Edited by AdamB

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The thing for me is that SLS suits the touring very well; great when the cars fully loaded and it sets itself to the ride height needed etc. Obviously all that's lost if you convert to springs etc

 

However, each to their own on this. But you do read/see a lot of updates where folk have done a spring conversion and then go back to the SLS system etc

 

Decent shocks all round (ie Sachs Sport spec) with Eibach pro kit springs up front and SLS on the rear for me, is the ideal solution if you don't want to go to coilovers and that expense 

 

This is mine on just that; as per my sig:

 

On E38 Style 37s:

 

sideonandsettled.jpg

 

On previous LM reps:

 

newboots1.jpg

 

And currently on winter Style 66s and winter tyres:

 

winterson1.jpg

 

Perfect ride height front and rear; hardly catches any speed humps anymore (unless they're stupidly large) and it handles great. The only consideration for me is to fit the Eibach rear ARB with poly bushed ARB bushes to wind the rear end in a bit more and stop the bit of body roll there still is

 

But that's a job for Spring next year onwards for me

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When you check for leaks check also the receivers and piping.  Forum posts have had people reporting receiver failure due to rusting internally (pin holes from moisture I think).

 

They are a PITA to change I believe but most of the time it's air bags as they are rubber and getting old now on e39s.

 

Don't leave it if it is an air bag  I would suggest as whilst most air bags fail slowly I had one fail with a bang while doing 60 on the A1 and it made handling interesting.

 

I changed mine for Arnott replacements and they have been great.  They use Conti rubber.  One size fits sport and non sport suspension.  Easy to fit.

 

Some of the other replacement brands such as aerosus get mixed reviews and the OEM ones are v expensive.

 

I agree with Dan.  I like the SLS on the touring.

Edited by Dbcrd

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It shouldn't drop in height at all, I can leave mine for a week and after starting engine, compression won't need to turn on, because hight is correct. Take soapy water an spray everywhere around air bags, pipes, connectors and receiver tanks, because they are quite rusty living underneath car all those years. It might be hardest part to inspect those tanks, because they are above subframe, so not so easy to reach, plus top side of them is not easy to see, so if there's a leak, it will be hard to notice.

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I have a friend with a ramp, that’ll be a start. I also have cans of leak spray... similar to soapy water, but it doesn’t run so quickly.

 

hoping it’s a bag/line, as that’ll be easier.

 

don’t mind if it’s an air tank, if I can diagnose it, like I say, half expecting to pull subframe off next year anyway.

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Out of interest, would people go for the arnott bags over genuine bmw? - mines a sport touring, and has the factory tow-bar, which I’d like to occasionally use.
 

I’ve got a few hours tomorrow, so I’ll try and spray the fittings/lines inside the car.

 

Are there any other common places? Wondering if the bags were replaced somewhat recently that the problem might lay elsewhere. - or is it more likely a bag issue again?

 

I've seen a video showing the unit under the spare wheel disassembled, but he literally soaks everything (incl the wiring connectors!) - he does actually find the leak in the solenoid by literally submerging it in a pot of water.

 

failing that, the bags/tanks will have to wait until I can get it up in the air to have a proper look.

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6 minutes ago, AdamB said:

Out of interest, would people go for the arnott bags over genuine bmw? - mines a sport touring, and has the factory tow-bar, which I’d like to occasionally use.
 

I’ve got a few hours tomorrow, so I’ll try and spray the fittings/lines inside the car.

 

Are there any other common places? Wondering if the bags were replaced somewhat recently that the problem might lay elsewhere. - or is it more likely a bag issue again?

 

I've seen a video showing the unit under the spare wheel disassembled, but he literally soaks everything (incl the wiring connectors!) - he does actually find the leak in the solenoid by literally submerging it in a pot of water.

 

failing that, the bags/tanks will have to wait until I can get it up in the air to have a proper look.

I have heard good reviews about arnott bags, but don't have any experience personally.  

About testing leaks - if you say those bags are replaced not too long ago, might be good idea to inspect connectors on top of airbags, maybe that's where they leak.

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I have arnott on my car and they are fine.  Check out the posts on other forums.  I think range rover people like them. 

 

https://www.bimmerforums.com/forum/showthread.php?2261840-Arnott-Rear-Air-Springs-(Self-leveling-Air-Bags)-Anyone-used-these

 

I came to the conclusion that arnott were the best choice.  Mixed quality reviews for aerosus I think. 

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So as an update, I sprayed the bags from through the wheels - no visible bubbles from peeing through spokes, bags look in good condition really

 

sprayed the fittings on top, no bubbles

 

sprayed the visible pipes- nothing.
 

Sprayed the joiner by the control module - nothing.

 

looks like it’s potentially the tank(s) or something in the compressor/solenoid unit under spare wheel :unsure:

 

I’ll still re-check the bags when it’s up in the air and I have more access

 

any tips for checking the solenoids etc?

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15 minutes ago, AdamB said:

So as an update, I sprayed the bags from through the wheels - no visible bubbles from peeing through spokes, bags look in good condition really

 

sprayed the fittings on top, no bubbles

 

sprayed the visible pipes- nothing.
 

Sprayed the joiner by the control module - nothing.

 

looks like it’s potentially the tank(s) or something in the compressor/solenoid unit under spare wheel :unsure:

 

I’ll still re-check the bags when it’s up in the air and I have more access

 

any tips for checking the solenoids etc?

 

Don't rule out the sensors either. 

 

If they're failing or failed, or the arms are damaged, they can cause issues too. 

 

Remove them, clean the connections, grease the ball joints on the arms and refit. See if that makes any difference 

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8 minutes ago, d_a_n1979 said:

 

Don't rule out the sensors either. 

 

If they're failing or failed, or the arms are damaged, they can cause issues too. 

 

Remove them, clean the connections, grease the ball joints on the arms and refit. See if that makes any difference 

Won't be sensors, when car is turned of, without air leaks, car should remain the same height. Because once electrics go in rest mode, SLS system is inoperative. And with faulty/stuck sensor car won't inflate bags up to correct height every time, when you start the car. It's definitely a leak somewhere. 

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Took the car out for a drive today anyway and had it running for a good while whilst I was spraying everything.

 

it’s been parked up since about 3pm with no noticeable drop. I’ll check it again in the morning.

 

It doesn’t appear to be a fast leak. I think I’m going to try and look at the bits under the spare wheel next as they’re somewhat accessible.

 

knowing my luck, it’ll be the tanks.

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Solenoids and pumps available from aerosus:

 

https://aerosus.co.uk/bmw/5-series/e39/bmw-5-series-e39-compressor-valve.html

 

I might try and find a solenoid from an e53 (more common) and swap it over. If it fixes it, happy days. I can then just plan a new valve as a future maintenance.

 

ive seen rebuild kits for pumps, which again I could do if I get a cheapish e53 unit.

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17 hours ago, AdamB said:

Solenoids and pumps available from aerosus:

 

https://aerosus.co.uk/bmw/5-series/e39/bmw-5-series-e39-compressor-valve.html

 

I might try and find a solenoid from an e53 (more common) and swap it over. If it fixes it, happy days. I can then just plan a new valve as a future maintenance.

 

ive seen rebuild kits for pumps, which again I could do if I get a cheapish e53 unit.


I changed everything on our rear suspension & it was still sagging after. It needed that valve block, has been perfect ever since. 
 

It never did sag till one of the accumulated tanks burst. All the messing about changing those then the bags after with lots of extra pumping up & letting all the pressure out again seemed to do in the valve block....

 

They are a bit pricey & I tried everything first but the new block was worth it in the end. 

Edited by Andyrt200
More info

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If I can do the valves and it fixes it then I’ll be happy.

 

if I end up having the subframe off at a later date, I’ll replace the tanks to save having it all off again. The ones on there won’t last forever.

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On 12/16/2020 at 7:34 PM, AdamB said:

Thanks for replies guys, at this rate, I’ll be doubling what I’ve spent on the car...

 

Welcome to E39 ownership. I'm finding the same since I bought mine in October!

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14 hours ago, AdamB said:

If I can do the valves and it fixes it then I’ll be happy.

 

if I end up having the subframe off at a later date, I’ll replace the tanks to save having it all off again. The ones on there won’t last forever.


Sorry I should read more carefully! I was assuming you done those. 
 

I’d forgotten but you saying about doing the tanks later reminded me, a good many years ago ours did have a very slight sag that started to get progressively worse. I just ignored it till the tanks on the sagging side burst on hitting a pot hole. It was rusty as hell & obviously was leaking a tiny bit before letting go in a big way. 
 

I didn’t want to drop the subframe at that point so just put one new accumulator under the boot floor:
VOSEZLx.jpg

 

They almost fit there but just needed that bit of wood to stop the bit of flooring resting on the tank. 
With that front bit of flooring in & the back seat up you don’t notice, with the seats down there is a bump in the nice flat load area. You can’t put the corner anchor points back in either. 
 

It was fine like that for a little while but the original bag must have got damaged when the tank burst & the car dropped to the floor, it started leaking so I put a new bag on & that was fine. 
 

But I thought I really should do the other side too as is was bound to start causing problems, but after putting the new bag & tank on that side it started to slowly sag, that side had never sagged before I started changing bits! That’s when I found needed the new valve block. 

(I actually rebuild the whole rear end changing every arm & bush with the subframe dropped enough to put the tanks back in the proper place before doing the valve block but there’s no reason they can’t both work fine under the boot floor) 

 

 

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21 hours ago, Nick E said:

 

Welcome to E39 ownership. I'm finding the same since I bought mine in October!

 I’ve already had an e39 for the past 6 years, (and my dad owned it from new before) never had to fix this much!

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7 hours ago, Andyrt200 said:


Sorry I should read more carefully! I was assuming you done those. 
 

I’d forgotten but you saying about doing the tanks later reminded me, a good many years ago ours did have a very slight sag that started to get progressively worse. I just ignored it till the tanks on the sagging side burst on hitting a pot hole. It was rusty as hell & obviously was leaking a tiny bit before letting go in a big way. 
 

I didn’t want to drop the subframe at that point so just put one new accumulator under the boot floor:
VOSEZLx.jpg

 

They almost fit there but just needed that bit of wood to stop the bit of flooring resting on the tank. 
With that front bit of flooring in & the back seat up you don’t notice, with the seats down there is a bump in the nice flat load area. You can’t put the corner anchor points back in either. 
 

It was fine like that for a little while but the original bag must have got damaged when the tank burst & the car dropped to the floor, it started leaking so I put a new bag on & that was fine. 
 

But I thought I really should do the other side too as is was bound to start causing problems, but after putting the new bag & tank on that side it started to slowly sag, that side had never sagged before I started changing bits! That’s when I found needed the new valve block. 

(I actually rebuild the whole rear end changing every arm & bush with the subframe dropped enough to put the tanks back in the proper place before doing the valve block but there’s no reason they can’t both work fine under the boot floor) 

 

 

Thanks for this, I had considered it as an option (temporarily) after seeing someone local selling an e53 setup incl the tanks.

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