SL500 129 ADS ISSUE

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Hi Guys

I am a true 90's Merc Nut

Currently i have a 91J 60k 500SE W126 bought back after regretting selling it!

I have a 92J 2.5 16V Owned 14 Years,also have a 91J 260E 62k in beautiful condition,and a 89F 190E Auto

Have owned a 500E,2.3 16V,107 300SL,129 500SL, W123 280CE...you get the picture!

I have just bought a 129 SL500 with ADS2

The car has had all 4 spheres,front leg on drivers side as was knocking,issue is the knocking persists and the ride is shocking,clearly all firm,the car bounces down the road reminds me of the days when you turned Spax dampers to firmest settings!

The car has been seen by a couple of people who clearly know the fault is there but unsure what is.

The car raises and lowers correctly on the button but seems to have no damping

Been to main dealer who say no faults show but clearly too firm....any ideas as i am lost with this

[HumbleJim]

I have no idea but try here.

http://www.benzworld.org/forums/r129-sl-class/

A lot of knowledge on this forum.

[TimboL]

If the car bounces about, I believe that is generally held to be indicative of a failed air cell accumulator ('sphere'). Apparently the diagnostic is to get them off, and poke something into them to check the membrane inside is intact. I don't know about the knocking.

I've also had the valve block, fail but that just showed the fault light on the dashboard (no bouncing), although there was a creaking noise from it for a few weeks before it finally seized up and it threw the fault light.

I have a recollection of an accelerometer failing as well: again just the fault light and no bouncing.


> Been to main dealer ...

Two of those failed to diagnose the creaky valve block before it eventually seized. But then the same two also happily re-gassed the a/c without noticing there was a hole in the heat exchanger big enough to have it loose all pressure within a couple of days.

A&A Merctech in Hoddesdon maintain mine, and they seem to remember more about the workings of R129s than anyone left at any of the various mail dealers that I used to take it to before that; plus they have the diagnostic equipment for ADS II. But they might be bit out of the way if you're in Surrey.

The service manual contains some general description of how it works. If you don't have access to that, Googling r129-ads-ii.pdf will find it for you.