Self Leveling suspension

[WillyG]

Hi

I hope that this is not a stupid question. . . if it is, please forgive my ignorance - how do I find out if my 1988 E32 735i has self leveling suspension? My car seems to be sagging at the rear. VIN is WBAGB620101662525 if it helps.

many thanks

[mojocoggo]

Only cars that end in "iL" have self-leveling suspension. Your car does not. Lucky you!

[Am3n]

Wait is there anychance my 740IL has it? It sits really really low but im hoping its just back shocks.

[WhiteSe7en]

Wait is there anychance my 740IL has it? It sits really really low but im hoping its just back shocks.

If I'm not mistaken, all iL's have the SLS. If it's sitting low, more than likely your suspension is worn out. The self leveling portion of the suspension is confined to the rear of the car.

[Am3n]

Well its the rear thats low... :(

[WhiteSe7en]

Well its the rear thats low... :(

The good news is that there is a conversion kit which converts the SLS to a conventional suspension. Most, if not all iL owners when faced with repairing an SLS, usually opt for the conversion kit. The SLS is nice to have if you have your car loaded with passengers on a frequent basis but if not, you really don't get any benefit from it.

When it comes time to confront this issue with my car, I'll go with the conversion kit

my .02 cents.

[shogun]

Do not mix up E32 and E38. 1997 is E38.
Check here with your VIN
http://bmwfans.info/

[Qsilver7]

Listen to shogun! There was some incorrect info given in some of the posts above. :nono

First, we are a multi-generational 7 series forum...so using words like "ALL" have to be used cautiously...plus we are also an "international" forum and some things apply to some markets, but not all. :)

In the USA market...the rear self leveling suspension was standard equipment on all of the "iL" models...but this is NOT true for e38 7 series.

The rear self-leveling system is useful for MORE than just hauling passengers and luggage...it creates a driving experience that enhances the entire driving dynamic of the car...that's the reason you will also find SLS/LAD on some Tourings & M5. Because the rear end of the car is always maintained at a specific level...it affects how the car handles when ever the rear end moves beyond those parameters...like in corners, humps, undulating pavement, stopping or hard braking...again, anytime the rear end moves beyond a set point, it is brought back to level which is transferred into a more dynamic driving and handling experience. I know this first hand because I've had one with and one without SLS/LAD...and it was VERY noticeable over a particular challenging stretch of road. My e32 always stayed stable over a stretch of concrete road that caused my F150 truck and the E38 to rock back and forth like a hobby horse (front to back).

I'm not sure that everyone replaces the SLS/LAD system either...it depends on what the problem is. Many times the only problem with the system is that that "bombs" (pressure accumulators) need replacing. They have a nitrogen (?) filled bladder inside that bursts or leaks and no longer compresses properly against the fluid inside the bladder. The bombs aren't that expensive and aren't that difficult to replace. Unlike the shocks which are expensive and last a lot longer than the bombs.

And it's been posted many times here...that it's VERY easy to tell if you have SLS/LAD if you just pop open the hood and look at your power steering reservoir...and the E38 its even easier because the owners manual has a really good illustration of the two reservoirs. The topic of Pentosin CHF 7.1 or CHF 11 S and ATF fluids are also oft mentioned on the forum and those also help determine if you have rear self leveling because it is engraved into the lid of the reservoir or on a label near the reservoir.

Hope this helps clarify things. :D

(E38 owners manual)
http://www.bimmerboard.com/members/q/original/E38%20Power%20Steering%20Reservoirs%20.jpg

[WhiteSe7en]

First, we are a multi-generational 7 series forum...so using words like "ALL" have to be used cautiously...plus we are also an "international" forum and some things apply to some markets, but not all. :)

That's why I prefaced my statement with "If I'm not mistaken". It didn't even occur to me that he was talking about an E38 because the OP's question was regarding an E32 so that's where my mind was at the time. Being an E32 owner, when he said 740iL, I didn't even think about the E38. When I said "all iL's", I was referring to E32's specifically. My bad for not clarifying what model he was referring to.:(



The rear self-leveling system is useful for MORE than just hauling passengers and luggage...

I was voicing an opinion here based on my own experience with both an "i" and now an "iL" At any rate, next time I'll make that clear.



I'm not sure that everyone replaces the SLS/LAD system either...it depends on what the problem is.

I never said "everyone" replaces the SLS/LAD system but what I did say is that "most, if not all" do opt to convert it to a conventional suspension most likely (IMHO) because it's far less expensive to maintain. This statement was based on the experiences I encountered while in the market for an E32 several years ago. The cost of replacing or repairing an SLS is usually more than the value of the car, which is why I prefaced that statement with "most, if not all".

Just thought I should clarify my previous statements:D

[E34freak]

Here is a self leveling suspension from a 1995 740IL. Before you convert your system and delete the self leveling you may want to think about replacing it with this one. It was from a front damaged car with 198 miles on it. It is like new and has been sitting in a warehouse for 13 yrs. The advantage of doing the whole system is you get almost new shocks brakes axles differential sway bar links and so on. I am not selling it cheaply 1000.00 plus shipping but if you are converting or replacing it will cost you as much or more. I am not sure if this unit plugs into your car since its a newer model but it should not be difficult to find out.

[E34freak]

opps I thought your car was 1998..........88 will not work.....sorry about that

[dophineh]

SLS is a pain IMHO. Makes it harder to lower it.

[WillyG]

thank you all for your input

WillyG

[SergeBMW]

This might be wierd but for some hella reason, the rear of the bimmer is NEVER EVER the same height, sometimes it sags and sometimes its a monster truck, and I have a 1989 735i, arent the IL supposed to have it? Anyone else have simialr symptoms on there "i"???

[WhiteSe7en]

This might be wierd but for some hella reason, the rear of the bimmer is NEVER EVER the same height, sometimes it sags and sometimes its a monster truck, and I have a 1989 735i, arent the IL supposed to have it? Anyone else have simialr symptoms on there "i"???

Yes, all E32 IL's have SLS. When my car is sitting and not running, it looks as if it's lower in the rear, however, when I start it up, it levels out.

[SergeBMW]

See thats the wierd reason, when the car is running for a bit, it levels out, and I have a 735i!!! Mabey the L part fell off :)? Should I check the vin?

[WhiteSe7en]

See thats the wierd reason, when the car is running for a bit, it levels out, and I have a 735i!!! Mabey the L part fell off :)? Should I check the vin?

Well that's definitely a sure fire way to determine what model you have.

Not that this is definite evidence of an "iL" but, does your's have the wood grain shift plate? It is my understanding that the "iL's" also came with the wood grain plate. My previous 7 was an "i" and it had a leather shift plate and no SLS.

If you want, you can check your VIN at the link below, which is free.

http://www.is-it-a-lemon.com/free.html

[SergeBMW]

Wood great shift plate? is that the actuall shifter handle or the plate where you can put the junk on? Because the flat peice below the shifter handle is wood, I will check my vin as soon as I take a shower lol, im a mess. Thanks for the help!!!

[rogan999]

How can i tell if it is the "Bombs"

People complain that the back is a bit uncomforable when hitting bumps cause it has a hard ride?

[Qsilver7]

You can also enter the last 7 digits of your car's VIN at any of the sites below and get details that are specific to your car...3 of them are the online part databases which gives the details of your car somewhere on the page when you enter the last 7 digits of the car's VIN:
http://www.bmw-z1.com/VIN/VINdecode-e.cgi (engine, tranny, fluid capacities, etc)
http://www.realoem.com/bmw/select.do (enter 7 digits and all the tabs will automatically fill out...and there's a line at the bottom that also details what the car is by the VIN
http://bmwfans.info/original/ (enter 7 digits and car info will appear on far right of page)
http://www.bmwmobiletradition-online.com/bmw/ (enter 7 digits and all tabs will automatically fill out...and there will be car's info on the far right of page)

[WhiteSe7en]

Wood great shift plate? is that the actuall shifter handle or the plate where you can put the junk on? Because the flat peice below the shifter handle is wood, I will check my vin as soon as I take a shower lol, im a mess. Thanks for the help!!!

It's the plate that the shifter sticks out of. The reason that's not a definite sign it's an "iL" is because I've known guys with "i's" that have replaced the leather plate with a wooden one. I was going to do that with my "i" but I didn't want to replace it with a new one for over 200 bucks. I spent a couple of years looking for one in good shape in a junkyard and never found it. I went on Tuesday to a junkyard to find a couple of parts for a 93 Buick Century which I'm selling and instead found two E32's, one was an "i" and the other an "iL". The "iL" had a wooden shift plate which was in perfect condition so I bought it for $25.00 to replace my old and sunlight faded one. Anyway, a lot of guys replace those so I would check the VIN to be sure.

[NEVector]

i am reading this thread today and thinking the rear of my car rides a little lower than the front and with it being an "il" it must have this system. I go out to see if it levels out when running and no such luck. My next step was to check the reservoir and the fluid in there is pitch black. I dont know what the previous owner put in there but I am guessing it was not correct. I ordered 2 pints of pentisin and plan on changing the fluid in there. My question is does this system work partially or is it an all or nothing deal. I have no warnings for the system on the dash and no driveability issues. Would the car ride ok if the system was shot? Thanks for any help

[WhiteSe7en]

i am reading this thread today and thinking the rear of my car rides a little lower than the front and with it being an "il" it must have this system. I go out to see if it levels out when running and no such luck. My next step was to check the reservoir and the fluid in there is pitch black. I dont know what the previous owner put in there but I am guessing it was not correct. I ordered 2 pints of pentisin and plan on changing the fluid in there. My question is does this system work partially or is it an all or nothing deal. I have no warnings for the system on the dash and no driveability issues. Would the car ride ok if the system was shot? Thanks for any help

I'm pretty sure it's all or nothing with the SLS. Either it works or levels according to load or it doesn't. There is a possibility that a previous owner converted it to a conventional suspension and your shocks are worn out. If it rides sitting low and doesn't raise up at all, it sounds as if your SLS either isn't working or it's not there anymore.

As for whether or not it would ride ok with the system shot, I don't know. I would imagine that there would be a noticable difference in the ride.

If the previous owner used the wrong fluid(ATF), it could ruin your seals so change that out ASAP. The SLS requires Pentosin hydraulic fluid so anything short of that, could cause irreparable damage to your system. If your not sure which fluid to use, it tells you on the reservoir cap.

Good Luck!!

[SergeBMW]

Well I found out that my 7er is not an "iL" so, that must mean someone replaced the rear suspension or are there normal self leveling shocks?

[SergeBMW]

Oh BTW, my dad got all cautios of me taking pic of the VIN thinking I would give EVERYONE my VIN, is it true that you shouldnt give out your VIN? I mean Willy G did it.

[WhiteSe7en]

Oh BTW, my dad got all cautios of me taking pic of the VIN thinking I would give EVERYONE my VIN, is it true that you shouldnt give out your VIN? I mean Willy G did it.

Personally, I don't like to give out anything however, as long as the title is in your name, I don't think it matters. Besides, someone could get your VIN off the car without your knowledge anyway.

[WhiteSe7en]

Well I found out that my 7er is not an "iL" so, that must mean someone replaced the rear suspension or are there normal self leveling shocks?

Yes there are but I believe to do somthing like that, it would take more than just replacing the shocks. I can't imagine anyone going to that kind of expense and trouble.

[SergeBMW]

Oh ok, and youve made a great point LOL.

[SergeBMW]

lol we posted at the same time, well this guy was into racing, the previous owner, and he had his track ready Porsche 911 Turbo, a Ferrari and another BMW, forgot which one, but he said he used to take this my bimmer to the track and did drive it at fast speeds, mabey thats why he added the self leveling suspension? Could be.

[CaptHerb]

lol we posted at the same time, well this guy was into racing, the previous owner, and he had his track ready Porsche 911 Turbo, a Ferrari and another BMW, forgot which one, but he said he used to take this my bimmer to the track and did drive it at fast speeds, mabey thats why he added the self leveling suspension? Could be.
Check the fill cap to see if it says ATF or CHF 7.1 / CHF11

[SergeBMW]

It says ATF, why? what does that mean?

[WhiteSe7en]

It says ATF, why? what does that mean?

Automatic Transmission Fluid, meaning it's not SLS. Duh!! I don't know why I didn't suggest that before, must be old age creeping up on me.

[SergeBMW]

Ok well thanks everyone, not I have to figure out what kind of struts these are lol

[94bimmer740il]

mine has the SLS

http://i119.photobucket.com/albums/o122/losymis/pictureofbluandkidshikingbeemer3-1.jpg

[NEVector]

I have emptied out the reservoir and replaced with pentosin 7.1 using the "turkey baster method" three times . It keeps coming out pitch black. Is there a way to comlpetely drain the whole system because at $14 a quart this is looking to be a long process. Another thing is when the black fluid was in there I had no whine from the power steering but as soon as I started to replace it with the correct fluid I now have an occasional whine from the pump. Also what is the capacity of the SLS system? I dont understand how the fluid changes from green to black so fast. Thanks for any ideas!! :eyecrazy:help

[shogun]

Thw color change is the same like with engine oil. There are abrassive parts from rubber gaskets inside etc.
The total volume of the LAD system is close to 2 litres, if I remember correctly it is 1.8 litres.
Flushing: here something from an Audi site
http://www.20v.org/pentosin.htm
Here drawings by IceTea about possible points to drain the fluid
http://www.bimmerboard.com/forums/posts/438575/

Whining: best is to flush the whole system, there are tiny channels in the system for example the power steering pump, all the dirt etc. is in the flid (same like in old engine oil), it makes these channels smaller in diameter, can sometimes block them etc.

flush, replace, flush...... filter change etc.
http://www.bimmerboard.com/forums/posts/447181/

[jmbinion]

do any "I" versions come with sls? i could swear my car goes up/down. maybe im trippin...

[shogun]

very, very rare, I do not know if they ever were imported to the U.S. But it could be ordered as optional extra for any E32 in Europe, but that was pretty expensive as option.
There people which used the E32 as tow car for their campers or horse + boat trailers bought them mostly.
But you can easily find out on your car: if the bottom of the rear shock has a hose connection for hydraulic fluid, you have LAD.
Or let some people sit in rear and/or on trunk, so that the rear goes down, then start engine, if rear goes up = LAD.

[94bimmer740il]

what can we do with your VIN?..I mean for real? Oh yea, we might be able to steal your radio code with it. LMAO

[Qsilver7]

what can we do with your VIN?..I mean for real? Oh yea, we might be able to steal your radio code with it. LMAO

Actually...you can't even do that! The radio CODE is based on the radio's serial number...not the car's VIN.

If the radio CODE was based on the car's VIN...then there are thousands of BMW anti-theft radios that will NEVER be able to retrieve their CODES because they have been removed and reused in multiple other BMWs over the decades...and at this point...no one knows what the VIN is of the car it was originally in. :dunno

For instance, the radio in my e34 Touring was purchased from someone on the forum...I have NO clue as to what car it came out of...nor what its VIN was/is....what model or what year. :dunno. But if I didn't have the radio CODE...I could slide it out from the dash and get the serial number off the back of it...then ask a BMW dealer to retrieve the CODE for me. :D

[Hwalker1]

That's incorrect. I own a 2001 740i built for the Japanese market. It has self levelling suspension complete wit a switch to turn it on and off on the dashboard. It's not an iL!

[shogun]

you are in the wrong forum, here is the E32 forum, your 2001 740i is an E38. However, as the E38 uses the same system for SLS and the regulating valve on the rear is basically interchangeable with E32 (except the lever), I assume you mixed up the fully hydraulic SLS/LAD with EDC , EDC has a switch, but not SLS/LAD . EDC can come along with SLS/LAD on the rear, but that is still hydraulic and adjusted by a lever on the rear axle, no switch. And the double vane power steering pump contiuously pumps and pumps and you cannot switch it of with a simple switch. So you either mean EDC or ASC switch on your car.
EDC = electronic damper control https://www.bimmerforums.com/forum/showthread.php?2369598-s-edc-problem
E38: Electronic damper control III Plus
The electronic damper control III Plus (EDC III +) is an electronic damping force control system.The aim of the system is to adapt the necessary damping force of the vibration dampers to current driving and road conditions such that maximum driving safety is achieved in conjunction with the highest possible degree of comfort.For this purpose, the system features following sensors to record the driving situation: Steering angle sensor,speed sensor, front body acceleration sensor, rear body acceleration sensor.
Dependent on these sensor data relating to the driving situation, the EDC control unit switches the damper valves integrated in the shock absorbers in the stages "soft", "medium" or "hard". With the aid of the EDC program button, the driver has the option of selecting two different programs:The "Sports program" is selected in button position "S" and the "Comfort program" in button position "K".In the sports program, the dampers are switched more rigidly oriented, i.e. the damper setting "soft" is avoided. In
setting "K", all three switching stages are operated, i.e. there is a sports and a comfort characteristic curve. Since the EDC programs ("Sports" and "Comfort") are selected by means of a button (no rocker switch), only the LED integrated in the button indicates which program is currently selected. When the LED at the "S" symbol lights, the EDC operates in the"Sports program", if the LED is off the system is operating in the "Comfort program".This, of course, only applies if the EDC system is intact.
Important!
If the EDC system is not operable (e.g. one sensor defective) or faulty to such an extent that reliable road adhesion can no longer be guarantied under all conditions, the safety concept (integrated in the software of the EDC control unit) switches off the entire EDC system.In this case, the LED in the selector switch goes out even if the "Sports program" is active. To ensure continued save vehicle operation in the event of such a system failure, the power supply to the damper valves is cut, i.e. they are operated in the fixed stage "hard".Although vehicle damping is then rigid, it can be further operated without any loss in road adhesion and the next service workshop can be visited safely.
General information
The EDC III Plus system has diagnostic capabilities.Disturbances on the supply and signal lines of the damper valves, defects and illogical behaviour of the system sensors and their corresponding lines are stored in the defect code memory of the control unit.
Note: Faults in the EDC system found by the defect code memory can be examined and rectified by way of the program point "Test modules".
EDC program button: In line with the operating philosophy of the E38, the EDC programs are selected by means of a button (in contrast to the rocker switch in earlier EDC systems). The program button is marked with "K" for "Comfort program" and "S" for "Sports program". When the sports program is selected, the LED lights at the "S" symbol.The LED remains off when the comfort program is selected. The button lighting is dimmed when the headlights are switched on.
Important! : If operation of the EDC III Plus system is persistently disturbed, the system is switched off, the LED in the program button remains off.
Steering angle sensor: The task of the steering angle sensor is to record the steering wheel angle while driving.
The EDC control unit processes both the real steering angle as well as the steering angle speeds, i.e. changes in angle. In this way, the variables of the steering angle as well as the steering angle speed have an influence on the switching logic of the EDC system. The steering angle sensor is mounted on the steering column spindle.The sensor consists of 2 wipers offset by 90 degrees. The measuring range of the steering angle sensor extends from 180 degrees left to 180 degrees right and the straight-ahead position, i.e. the centre position of the steering wheel marks the 0 degree setting.
Important!: If the steering angle sensor is changed or if it is necessary to carry out work on the front axle system, front wheels/steering system, the so-called steering angle offset must be carried out on completion of this work.The diagnosis program is used for this purpose. The steering angle offset is selected under the point SERVICE FUNCTIONS. After setting the front wheels in the straight ahead-position, the control unit carried out the offset procedure automatically after pressing the confirmation button. The 0 degrees setting of the steering angle sensor now agrees with the physical straightahead position of the front wheels. Slight deviations which may occur because the straight-ahead position of the steering wheels can only be set by eye, are compensated by the EDC control unit itself when driving. The EDC control unit powers the steering angle sensor with a 5 Volt supply.Data transfer to the control unit takes place via 2 signal lines.
Front acceleration sensor: The front acceleration sensor records the acceleration of the car body at the front in vertical direction. The body acceleration is caused by the reaction of the car to the road surface. In addition to the absolute acceleration, the acceleration frequency is also recorded, i.e. the changes in acceleration (spring deflection/rebound), in other terms the vibration frequency of the vehicle body. The acceleration sensor receives a 12 Volt supply from the control unit. A voltage value between 0 and 5 Volt is output to the control unit at the signal output of the sensor. A value of 2.5 Volt represents the rest position (acceleration = 0), the values 0 Volt and 5 Volt are the maximum acceleration values.
Important!: In order to check the function of the sensor, "front acceleration sensor" can be selected in the diagnosis program under the point "Function test".
Checking outside the vehicle: Remove sensor, connect to 12 Volt supply and check the function by measuring the voltage at the signal output while at the same time moving the sensor. If the sensor is operating correctly, the measured voltage value is varied between approx. 0 and 5 Volt (depending on degree of movement, i.e. acceleration magnitude). Installation location of sensor:Right-hand spring strut dome on side panel behind splash guard.
Rear acceleration sensor
The rear acceleration sensor records the acceleration of the vehicle body at the rear in vertical direction. The body acceleration is caused by the reaction of the vehicle to the road surface.In addition to the absolute acceleration, the acceleration frequency is also recorded, i.e. the changes in acceleration (spring deflection/rebound), in other terms the vibration frequency of the vehicle body. The acceleration sensor receives a 12 Volt supply from the control unit. A voltage value between 0 and 5 Volt is output to the control unit at the signal output of the sensor. A value of 2.5 Volt represents the rest position (acceleration = 0), the value 0 Volt and 5 Volt are the maximum acceleration values.
Important!: In order to check the function of the sensor, "front acceleration sensor" can be selected in the diagnosis program under the point "Function test".
Checking outside the vehicle: Remove sensor, connect to 12 Volt supply and negative and check function by measuring voltage at signal output while at the same time moving the sensor.If the sensor is operating correctly, the measured voltage value will vary between approx. 0 and 5 Volt (depending on movement, i.e. acceleration magnitude). Installation location of sensor:Rear RH spring dome, accessible from luggage compartment after removing the trim.
EDC valves for chassis dampers
Newly developed vibration dampers with integrated valves operate in the EDC III Plus system. Contact of the connection is made by the piston rod. The two valves are switched in combination such that three damping force stages are made possible : Damper stage "hard", damper stage "medium" and damper stage "soft". In addition to the more compact design compared to the old EDC system, it has also been possible to reduce the weight of the new dampers.
Speed signal
The EDC control unit receives its speed signals from the front left wheel speed sensor of the ABS system. From this speed sensor, the signal is transferred to the ABS control unit which in turn sends the signal to the EDC control unit. The speed signal received by the EDC control unit is a square-wave signal (0 to 12 VOLT). The corresponding cornering speed/lateral acceleration is calculated on the basis of the measuring variables vehicle speed and steering wheel angle. Calculating the change in vehicle speed renders a longitudinal acceleration sensor unnecessary.

[billleget]

I have a US spec E32 1988 735i with the SLS AND the top of the PS reservoir said to use ATF. Per Shogun's info, I flushed it out using Febi Bilstein equivalent to CHF 7.1. My build date was 10/87. Seems like no rhyme nor reason why BMW built i's and iL's with different options and PS fluid recommendations causing us to be confused.