LAD/self levelling elimination + LAD shock repair info

[shogun]

As "xlr8tin' asked me for it, here is the info, all from: bavauto dot com

under suspension & steering >>shocks>>shock installation>>>
Self Leveling Elimination Kit - Springs and Shocks Sold Separately - For Cars Without EDC
The part number for the springs for a stock type ride is 33 53 1 132 Part # : SLELIM KIT-E32 $149.95
edit 08/2019, bavauto link NLA as they closed, here is a saved copy http://www.bmwe34.net/E34main/Mainte...34ElimKits.pdf

Self-Leveling System Elimination

PURPOSE: This tech sheet will outline the general procedures for removing the hydraulic self-leveling systems on the noted BMW models, in preparation for Boge or Bilstein shock installation. Please note that this is not a detailed step-by-step instruction sheet. It is assumed that the installer is familiar with basic rear suspension service on these models of BMWs.
SAFETY WARNING: In preparation for performing this job, the vehicle must be raised and properly supported so that the rear
suspension has all vehicle weight removed and is hanging freely. Use appropriate safety procedures and precautions in lifting and securely supporting the vehicle. As the work will be performed overhead, safety glasses are also recommended.
NOTE: Additional parts are required for use with the Self-Leveling Elimination Kit:
• Rear BMW springs for a NON self-leveling version of the application or set of sport springs.
NOTE: 525i & 530i touring must use BMW springs due to increased weight of the touring body.
• Rear shocks for a NON self-leveling version of the application (525i & 530i touring use sedan shocks).
PARTS LIST: SLELIM KIT-E34M,SLELIM KIT-E34T, SLELIM KIT-E32, SLELIM KIT E38

PROCEDURE:
1. Disconnect the hydraulic hose, at each side, running between the rear shock and the accumulator (mounted to the rear inner fender well), at the accumulator.
2. Remove the rear shock and spring assemblies complete with the upper mounts and hydraulic hoses.
3. Remove the accumulators and the hydraulic hoses running from the accumulators to the distribution block. Remove the hydraulic hose running from the regulator to the distribution block.
4. Disconnect the attaching lever and connecting link from the swaybar and the hydraulic regulator valve.
5. Disconnect the pressure and return lines (coming from the engine driven pump) from the regulator and remove the regulator.
6. The pressure and return hoses must be rerouted and connected together. This can be done using the
supplied union connector (M10 x 1.0) at the ends of the hoses where they have been disconnected from the regulator (Figure 1 “A”) or further forward closer to the pump. The connection can be done at (Figure 1 “B”) using one of the existing union connectors and gently bending the hose and pipe (#1 & #2) and using the union to connect them together. The hoses CAN NOT be simply plugged. This will damage the hydraulic pump, which also supplies the power steering and power brakes.
7. Assemble the new springs, shocks and upper mount hardware from the Self-leveling Elimination Kit.
8. Install the Spring/shock assemblies into the vehicle.
9. Start the engine and check for leaks at the union of the pressure and return lines.

Drawing in link above
plus:
BMW Factory Coil Spring - Rear ( sold individually ) - 2 required * only for use with Bavarian Autosport Self Leveling Elimination Kit ( rear shocks must be purchased separately ) Part # : 33531132693 ,plus shocks, see info above

[sunt]

[corbinstein0]

anyone got pics of the lines where to hook them together near the engine?

[shogun]

the return line from the rear comes up from inside the left front wheel housing thru the opening where also the fuel lines go thru = not much space to work.

It is much easier just to block the lines as described by bavauto or to use a break pipe u-piece to connect the feed and discharge line from/to regulating valve.

Elimination of the LAD warning signal:
The switch is on the rear axle under the car, passenger side.
This one
http://www.bimmerboard.com/members/t...l/P1020957.jpg
http://www.bimmerboard.com/members/t...l/P1020955.jpg
pics are from my 10/1988 parts 750

You can arrange the switch that the warning signal does not light.

Or manipulate the check control module.
Detailed info:
http://forums.bimmerforums.com/forum...ht=ccm+pin+1+2

[donald123]

It says that the automatic leveling conversion kit is only good for For Cars Without EDC. How do I determine if my car has EDC or not? I drive a 1990 BMW 735IL. Nothing in the owner's manual says anything about EDC. Electronic Damping Control.

[shogun]

LAD is hydraulic and only on the rear.
EDC is electric and all 4 shocks have it then. Easy to find out if you have EDC, there is a switch on the center console with K= Komfort and S for sports.
If not, no EDC. L version came always with LAD, EDC was optional extra.

[rossg]

is there a way to just bypass the pressure hoses to the rear without buying the whole kit? what kind of springs would i need to get the back end up. can I use stock oem type springs from another model e32 without the lad system, if so which model? i have a 90 750 il that the previous owner has capped the accumulators and put in regular struts. Recently I removed the regulator and 1 of the lines was under a lot of pressure. Can I connect the lines in the rear or disable the system some way?

[shogun]

some use a brake line and make a u-bend and connect feed and return line , others just put a plug into the outlet of the regulating valve under rear axle towards the bombs (not possible if the regulating valve is leaking), that is same like the bavauto set arrangement.
I would connect both lines with a u-pipe, it must be made sure that the fluid is circulating.Springs: try the normal ones/oem

[bigcfromcinci]

What a PITA...I'm glad mine doesn't have that setup.

[Brian1965]

I used a tubing bender and connected supply/return at the driver sided wheel hosing. Bav auto kit comes with coupling. I would recommend removing lines and regulator. Then connecting near the top of the engine housing, or wheel well.

[rossg]

do you have a picture I could look at to see what you did? what size ends are on the line , what size tubbing is needed. My accumulators make a hell of a noise and I am tired of listening to it.
Shogun did these cars come without lad ? where do you recomend I get springs budget is small so the cheaper the better I am using helpers right now but that is a patch not a fix.

[shogun]

all L were with LAD. To make yourselves a picture of the tubing, lift the rear up and crawl under the car and you see the tubing.
Accumulators make no noise. They are just steel balls with a gas filled bladded, if the bladder is broken, all will be filled with Pentosin and the rear is stone hard. Must be something else.
I have cut off a bomb and explained it on youtube on my website, have a look.

In case you are on a budget, go for KYB, sometimes there are complete sets on Ebay. But you need also new shock mounts.
I would keep LAD, easy to repair for a DIYer.
The noise you hear might be the dogbones on the rear axle? That is often the case.

[mojocoggo]

Looks pretty similar to the E38 process, maintaining circulation. Use something strong like transmission fluid line.

[shogun]

better take screwed couplings and pipe or at least hydraulic pressure hose with design layout for >170 bar like the other hydrailic hoses for the U-line, the pump pushes the Pentosin with up to 130 or 140 bar. In case the rubber breaks and Pentosin suddenly leaks, that could cause damage to the double vane power steering pump.

[rossg]

I would like to put the lad back in but I would have to find complete strut assemblies. They are not easy to come by. I dont have a problem doing any repairs i have been fixing cars for over 20 years. I dont know why it makes noise but it is definitly in the back near the driver bomb possible air bubble or relief valve etc. With spring helpers installed and a fair ride height the noise goes away.
I agree that the bypass should be done with metal line not rubber hose to much pressure. looks like that line is near the front of the car? I will have to get it back on the lift and see if I can figure it out.

[mojocoggo]

better take screwed couplings and pipe or at least hydraulic pressure hose with design layout for >170 bar like the other hydrailic hoses for the U-line, the pump pushes the Pentosin with up to 130 or 140 bar. In case the rubber breaks and Pentosin suddenly leaks, that could cause damage to the double vane power steering pump.

Interesting. When I ran the car with no hose attached, the fluid was just barely dripping from the feeder line. It didn't seem like a high pressure at all.

[shogun]

the regulating valve under the rear axle has 2 valves, high reacts at p = 130 bar and the low at p = 30 bar.
That means: pressure between regulating valve and the bombs/shocks is max. 130 bar, if higher, the high pressure valve opens and fluid runs back to the engine room
http://www.bimmerboard.com/forums/posts/511327

[rossg]

Interesting. When I ran the car with no hose attached, the fluid was just barely dripping from the feeder line. It didn't seem like a high pressure at all.

when I removed the line at the accumulator a line was under supper high pressure and sprayed fluid every where.

the regulating valve under the rear axle has 2 valves, high reacts at p = 130 bar and the low at p = 30 bar.
That means: pressure between regulating valve and the bombs/shocks is max. 130 bar, if higher, the high pressure valve opens and fluid runs back to the engine room
http://www.bimmerboard.com/forums/posts/511327

yeah its the regulator http://www.bimmerboard.com/forums/posts/513896
same as that guy.

[mydejavooo]

I've read somewhere that EXTREMELY hard rear suspension (like, being unable to even push down on the rear bumper in order to make the car "bouce") is a sign of accumulator failure. Is that accurate, or is it a sign that the car is setup incorrectly? I have no idea if my LAD is working or not, but when I hit bumps and my teeth almost rattle out, I suspect that it's not! LOL!

Deja

[shogun]

yes, probably bombs are empty: see this explanation youtube I made
I have sliced off an LAD bomb
http://twrite.org/shogunnew/upgrades&fun/cutestuff.html

but also check the regulating valve height set up.

[rossg]

how do you charge the nitrogen after rebuilding the lad system?

[mydejavooo]

how do you charge the nitrogen after rebuilding the lad system?

That's my question as well.

Deja

[shogun]

the nitrogen is only inside the bladder inside the accumulator/bomb which is a closed system, see the video here
http://twrite.org/shogunnew/upgrades...g_up_the_bombe

there is no way to fill a broken bladder with nitrogen again, that is a dead part.
So you need a new bomb then.

Citroen in the old cars had a connection to refill their bombs again. But when it is broken, it is broken.
As far as I remember the pressure of the bladder filling is 25 bar.

[rossg]

ahh now i understand

[mydejavooo]

Just noticed that when I started my 740il today, the rear of the car raised up ever so slightly upon ignition....so I am assuming that the LAD system is working properly. Is that a correct assumption? Perhaps my "rock hard" rear end issues IS the result of improper adjustment of the rear strut assembly. Am I way off-base here?

Deja