R129 ADS - Front Too Low

[DanMorgan]

Hi,

I replaced a control arm on my R129 today but forgot to tell the mechanic to lock the suspension (with the button). Unfortunately, the front has decided it doesn't want to react to the button (going up or down), and it's also on the floor (barely driveable).

Once I got home, I plugged it into STAR and got the C1509 Vehicle Level Too Low and C1130 Level Sensor FA B22/2 errors. However, I was able to remove these error codes and also adjust the front via the STAR.

After unplugging the STAR and thinking that was that, I tested the ADS on the button by the headlights, and the front decided to drop to its lowest setting.

--

Am I missing/doing something wrong here?

Cheers,
Dan

 

[BTB 500]

Once I got home, I plugged it into STAR and got the C1509 Vehicle Level Too Low and C1130 Level Sensor FA B22/2 errors.

There's a ride height sensor under the car - check it's still securely mounted and the wiring to it looks OK. You can actually adjust the pushrod that operates it - I did this years ago as my car was sitting fractionally high at the front. IIRC I was able to access it with the car on the ground by turning the front wheels to one side.

My car once got jacked up without the suspension being locked for an MOT, and this blew a load of hydraulic oil out via the reservoir under the bonnet (so they told me). I didn't have any problems driving the car afterwards but I did have to top the oil up. Check this on yours ... if the level is very low it might be possible to get air in the system

 

[DanMorgan]

There's a ride height sensor under the car - check it's still securely mounted and the wiring to it looks OK. You can actually adjust the pushrod that operates it - I did this years ago as my car was sitting fractionally high at the front. IIRC I was able to access it with the car on the ground by turning the front wheels to one side.

My car once got jacked up without the suspension being locked for an MOT, and this blew a load of hydraulic oil out via the reservoir under the bonnet (so they told me). I didn't have any problems driving the car afterwards but I did have to top the oil up. Check this on yours ... if the level is very low it might be possible to get air in the system

I will take a look later on - To me, it just feels like it doesn't know what height it should be at (if that makes sense)

 

[BTB 500]

I will take a look later on - To me, it just feels like it doesn't know what height it should be at (if that makes sense)

The ride height (level) sensor controls that, which is why I thought it was worth checking. Particularly as the car has just had mechanical work done on the front suspension.

 

[DanMorgan]

I couldn't see anything - I will get the trolley jack from the garage when I am back from holiday.

The only way I can get it to stay at driveable height is by locking it in place. Do you know if its safe to drive it with the lock on at all?

Eventually, I do want to delete the system anyway and spotted the SL Shop have this -> Mercedes-Benz SL R129 Bilstein B12 Suspension Handling Lowering Kit - would this be all that's needed to swap it all over? (I will have to mess around with the hydraulic fluid of course)

 

[BTB 500]

I couldn't see anything - I will get the trolley jack from the garage when I am back from holiday.

The only way I can get it to stay at driveable height is by locking it in place. Do you know if its safe to drive it with the lock on at all?

Eventually, I do want to delete the system anyway and spotted the SL Shop have this -> Mercedes-Benz SL R129 Bilstein B12 Suspension Handling Lowering Kit - would this be all that's needed to swap it all over? (I will have to mess around with the hydraulic fluid of course)

I had a quick look under mine without starting it up and cranking the steering to full lock and couldn't see anything - sorry.

IIRC you are only supposed to move it very short distances at low speed with the suspension locked. The handbook should say though.

Not sure about deleting the system ... I suspect there might be more to it than that, to prevent the car from throwing errors. Touch wood mine has been very reliable - the only thing I've done in 20 years is replacing the accumulators (spheres), which have a limited lifespan due to the rubber diaphragm inside. I once had to park it across a speed hump which caused all sorts of bongs and warning lights when I started it again, I guess because the relative position of the wheels made it think something was wrong! I pulled over and turned the car off & back on and all was fine.

 

[DanMorgan]

I had a quick look under mine without starting it up and cranking the steering to full lock and couldn't see anything - sorry.

IIRC you are only supposed to move it very short distances at low speed with the suspension locked. The handbook should say though.

Not sure about deleting the system ... I suspect there might be more to it than that, to prevent the car from throwing errors. Touch wood mine has been very reliable - the only thing I've done in 20 years is replacing the accumulators (spheres), which have a limited lifespan due to the rubber diaphragm inside. I once had to park it across a speed hump which caused all sorts of bongs and warning lights when I started it again, I guess because the relative position of the wheels made it think something was wrong! I pulled over and turned the car off & back on and all was fine.

I will probably never sell the car, so I am willing to chuck some money at it, but I am just in the dilemma of overhauling it or having a conventional setup that'll be good for many, many years.

I always wanted it slightly lower too, which could be a benefit of going down the conventional route.

 

[BTB 500]

I always wanted it slightly lower too, which could be a benefit of going down the conventional route.

Pretty sure you can change the ADS ride height via Star (but bear in mind that it drops below a certain speed anyway). As mentioned the old skool (mechanical) method is to adjust the linkages to the level sensors.

 

[grober]

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[BTB 500]

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That's very helpful - I did wonder if it might be air in the system. As an aside the car in the video has the original ADS ... I think the OP's is ADS II as that has the suspension lock switch mentioned above. There's some technical info. on both ADS and ADS II here:

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