E39 Touring air spring/line and reservoir info for SLS

[jase007]

There seem to be a lot of questions about air lines / springs and their connections and "why does my touring sag ..."

I've replaced both air springs and one of the reservoirs on my touring. I have repeatedly posted individual images of the repair but thought I'd put most of them in one place for easy reference.

To access the tops of the SLS rear air springs you need to remove the carpeted interior panel located immediately behind the rear seat. There are threads with pics and a DIY instructions on this forum and others how to do so.

Once removed, you get to the good stuff.

Here are some pics of the air line junction / connections to the air springs in your touring:

Connection for top of air spring:

https://lh4.googleusercontent.com/-JPWc-Q7K6KM/UAFlelX0txI/AAAAAAAAMf0/hU3QSuAgj3Y/s640/brass%2520junction%2520with%2520instructions.JPG

Internal black plastic clip that can EASILY break when removing brass air connection at top of each air spring:

https://lh3.googleusercontent.com/-MgDprhI7sRc/UAFlLI_pydI/AAAAAAAAMfo/GyoDms6WhPY/s640/P1010023.JPG

How air lines attach to top of air spring:

https://lh5.googleusercontent.com/-0kW62zimFxA/UAFlwpmVpYI/AAAAAAAAMf8/xXW-5vHZEJg/s640/P1010024.JPG

Couple of things to note:

1. the large black plastic line goes to the air reservoir (two) tanks attached to the underside of the car. I have replaced one, they are a PITA to do. (remove diff carrier bolt, brackets, end of half shaft, etc...)

2. The black captive plastic pinch lock in the brass junction is NOT available separately. If you break it you need to buy a complete new reservoir and replace. PM or email me if this happens to you.

Air reservoir:

https://lh4.googleusercontent.com/-lP7hbPq8JMk/UAFuQ0knzCI/AAAAAAAAMgM/zDvMHofF6lU/s640/new%2520air%2520reservoir.JPG

3. The orange and blue small air lines from the air junction block (block is next to the control module, next to the battery) are connected at each end by small brass threaded collars that seal the air lines to either the brass junction at the top of the air spring or the air distribution / junction block next to the battery.

4. Unless you've messed with it ... these orange & blue air lines rarely ever leak. You could put soapy water on the connections and see if you get bubbles.

5. 99% of "sagging" problems are air escaping from the worn folded edge of the air springs and it is time for replacement. Typically done in pairs. Below is a picture of my old one next to a new one:

https://lh4.googleusercontent.com/-XhZixlQoxcQ/UAFo6nU4QaI/AAAAAAAAMgE/IiOynd3wnwA/s640/P1010032.JPG

There are threads on this forum and others about removing the one bolt at the bottom of the air spring and relieving the air pressure in the system before removing the attachment clips and brass junction / clasp from the top of the air spring... to then replace the air spring.

* Note: There are DIFFERENT part numbers for left and right air springs AND there are different part numbers for sport versus non-sport air springs.

Non-sport:

Pneumatic spring, left 37121094613
Pneumatic spring, right 37121094614

Sport:

Pneumatic spring, left 37121095081
Pneumatic spring, right, 37121095082



If you have (get) a copy of Ediabas / INPA software and an old laptop with a serial port and the required diagnostic cable (eBay) you can see and adjust the air pressures (r versus L) in the system.

Aftermarket vendors offer adjustable ride height sensor mechanical links that can "fool" or "trick" the EHC (electronic height control) system into lowering or raising the starting point of the ride height of the car.

FWIW, my touring is a sport model, 5-speed that already scrapes on speed bumps. I have NOT lowered it either by replacing (with aftermarket) the OE sport coil front springs or adjusting the "links" or base air pressure in the system in the rear pneumatic air springs.

Good luck. :)

[rl 325i]

Nice info !!!

[da9b16]

Because of the write up I had my passenger side done in under 45 min. Air Spring working great and been holding air now for over 48hrs no issues. Thanks!

I will take better pix of the lower bolt location when the other side comes in.

[jase007]

Great!

Glad it could help someone save time and $$$.

Cheers.

[cachefield]

Jason,

I got new springs in and it still leaks, so I bought new tanks and am ready to install them (reservoirs or accumulators). Could you provide instructions? I can't find any tank instructions in the Bentley. I assume you remove half axles from final drive flanges? Did you lower the subframe? Lower the exhaust?

Also, Bentley (p331-6) gives 3 torque values for the M10 torx bolts with ribbed teeth (my socket is stamped E12). M10= 64 Nm, M10 silver=80 Nm, and M10 black=100 Nm. My bolts are basically rust colored.

Thanks for any help! I have two sunny days--then rain.

Tom

I figured it out; though I still don't know what Jason meant by diff carrier bolt or brackets. First I PB blasted the half axle bolts and loosened them, freeing the axles from the diff. I still couldn't get the tanks free so I supported the diff with a 8x8 inch wooden block on a floor jack , loosened the 4 subframe bushing bolts and lowered the subframe, more or less one side at a time, after removing the bolt at the base of each airspring. It worked pretty well, though feeding the stiff hoses through the body floor pan was still a pain. I managed to break an infamous black plastic clip while feeding the second new tank into place. Fortunately, I hadn't broken either old clip, so I used one of them. Obviously I should have removed the clip before feeding it or asked for assistance.

I bet a real mechanic with a lift would completely lower the entire subframe.

The hardest part of anything so far was disconnecting and reconnecting the passenger side height sensor--the plug was extremely tight, hard enough to separate, and then I needed my channel lock pliers to put it back together. I was afraid of stretching the wire.

I'll finish putting it back together tomorrow, and look forward to seeing if the leak is gone.

Tom

[jase007]

Tom:

Sorry, I missed this thread update.

I didn't drop the subframe ... I lowered the diff by removing bolts. Only had to drop one half-shaft. IIRC, there were brackets for e-cable lines or other "stuff" that I had to move.

Threading the new reservoir lines through the body was the worst part for me as well. I taped up the brass heads and encapsulated black plastic clips to protect them when I threaded them through the floor and up to the top of the air springs.

My initial issue was a broken internal black plastic clip in the brass connector. I didn't want to take any chances and break the new one attached to the new reservoir.

Have you solved your air leak problems?

If it isn't the air springs, the connections/lines, the air reservoirs, the air line connection junction box ... then I'd next look at the solenoids in the air pump / clamshell in the spare tire footwell.

Have read where others in the UK have salvaged parts from spare pumps they picked up in pick-n-pull yards. One touring owner's issue was solenoids failed / failing at the pump.

[valtersboze]

Sorry to bring up a dead dog, but did you fix the issue replacing the tanks?

[jase007]

"Valter" (put your first name in your signature)

Which issue are you asking about?

This post has info for those looking to get the correct parts to replace their air springs.

What are you looking to fix on your 540iat?

Cheers.

[Tirefriar]

Don't mind if I piggy back on this thread. My 2001 E39 iT auto non-sport with 70k miles. Few days ago noticed that the drivers side rear sags. The passenger side is ok. I don't think its the pump as one side is good, the drivers side raises to proper level when car is running, no MIL for SLS on the dash. Initial thoughts were the bags, but now I am seeing that the reservoir/accumulators can also be an issue.

My wife's 2006 MB R 350 developed same issue and the culprit were rear air bags.

Am I looking at a bags issue on my E39 with only 70k miles? Interestingly the Benz has about the same mileage but the air suspension bags tend to go out every 70k miles, so the mileage for replacing bags on the Benz was in line...

[geargrinder]

Don't mind if I piggy back on this thread. My 2001 E39 iT auto non-sport with 70k miles. Few days ago noticed that the drivers side rear sags. The passenger side is ok. I don't think its the pump as one side is good, the drivers side raises to proper level when car is running, no MIL for SLS on the dash. Initial thoughts were the bags, but now I am seeing that the reservoir/accumulators can also be an issue.

My wife's 2006 MB R 350 developed same issue and the culprit were rear air bags.

Am I looking at a bags issue on my E39 with only 70k miles? Interestingly the Benz has about the same mileage but the air suspension bags tend to go out every 70k miles, so the mileage for replacing bags on the Benz was in line...

Really its more a rubber-age than miles thing. Supposedly cars in hot climates lose the bags much faster cuz of heat cycles. The rez's dont tend to fail on their own its more if the connector gets borked in process. Dont overthink it - most likely just that bag. Jack the car, pop it out, have a look - will prob be cracked and old - and if so, change it. Cheap and easy, unlike many other cars.

[valtersboze]

I am referring to slow leaking if replacing tanks fixed it for the previous post. Since my abs is dead i disconnected it, disabling the speedo at the same time which makes the SLS adjust itself even when driving. I replaced dead compressor but every 2-3 days i reconnect the fuse to get the level back up. I hear no hiss anywhere. No idea what should i look for.

[geargrinder]

1. You should look for somebody who can fix your ABS.

2. Re: the SLS, all the info is here. "no idea what I should look for". yeah. OK. How about read the thread and the other good ones. Tons of stuff to give you "ideas of what to look for". Number one with a bullet is check the bags. its probably a leaking aging bag. if its not that its very very rare to be the lines unless you messed them up doing work in the area.

[sienayr]

Thanks for this info! DO NOT TRUST RealOEM.com! I put my VIN in there, and even though I have M-sport suspension it gave me the part number for the non-sport air spring. If not for this helpful thread I would not have known the sport model has a different air spring. Called and got the part switched to the right one this morning, luckily the order had not shipped. Perhaps this is a lesson that others have already learned, but now I know, double check what realoem.com tells you!


Also- apparently BMW has raised the price on the air springs by $20 this month. Lucky for me I got my order in just in the nick of time!

[geargrinder]

Yeah i dont trust the VIN part all the time, in fact i never bother usually, but if you navigate to the right model with the menus usually it will show you the various parts choices - ie "for models with sport" etc. And then you can hand pick the one that applies. Sure sometimes theres an error... And sometimes the online version is out of date for superceded numbers but mostly its a great resource.

[AndyBlake]

So I broke the black captive plastic pinch lock in the brass junction. Is there anything that will work as an alternative to secure this once it's broken? I read where you said to PM you if it happens. Maybe you have some advice. 2001 X5

[juststeve]

So I broke the black captive plastic pinch lock in the brass junction. Is there anything that will work as an alternative to secure this once it's broken? I read where you said to PM you if it happens. Maybe you have some advice. 2001 X5

If you cannot find a salvage yard unit...

I would try a side mount or crimp-on retaining clip.
using just one will be too narrow, so stack several on each other or make a u-shaped spacer from a flat washer.
then use a single clip over the modified washer.
http://www.mcmaster.com/#circlips/=10gxbhd