450SEL 6.9 suspension conversion
 

I have been trying to fix my suspension height control valve on my 1979 450SEL 6.9 with no luck. Parts are very expensive and very hard to find, that pertain to the hyraulic suspension. I am considering to buy a good W116 parts car and swap out the suspension to eliminate the hyraulic. Please advise on what I may need to watch out for.

Its value will drop considerably if you change it like that. I'd try to keep it stock with the hydraulic system. If you can't afford to maintain/fix a 6.9, why do you have a 6.9? :D ;)

Go to starmotorsny dot com, click on "services", read the hydraulic trouble shooting guide. Neil can get anything you need, knows how it works. He is a long time supporter of the M-100 Group (600, 6.3, 6.9 club: m-100 dot cc)

You don't want to butcher what you have.

The best approach is to use a 450SEL donor. I owned a 6.9 that had a horrible spring conversion. I found it very hard to get past the mess that they made and eventually sold the car.

The 6.9 engine is very heavy. Even 450 front springs won't have the necessary stiffness. You could use all 450 parts but for the front springs. i would look for stiffer ones.

If you convert to steel springs you will need to watch out for bumps in the road because the nose will be sitting on the stops..:D:D:D
Parts are easily available for any 6.9 as Hanno says just ask Neil Dubey .He does rebuilt units for them .
The spring towers in a regular W116 don't exist in a 6.9 as the person who tried to convert Al's car found out . There is nowhere for the top of the spring to sit unless you weld in cups for them . then there is shock absorbers...and it will go on until you run out of interest or money.
Sell the car if you cannot run it,after all these were not only the best cars in the World,they were also the second most expensive car in the world after the 600.... And nothing has changed.

can't find a used valve? They're around. -CTH

I have decided not to do the conversion. Now I am on the looking out for a good used front height control valve. Can anyone tell me if the front and rear valves are identical?

Yes they are.

How different is the 6.9 leveling valves from say a TD rear sls valve? The TD sls valve can be easily rebuilt with a few O-rings.
I'm sure 6.9 owners have researched this already. Just a thought...

Very 6.9 SLS valves look completely different. They are shaped like cubes. I know that they are rebuildable because there is a shop in NY that rebuilds these and the 6.3 valves. I don't know how easy they are to rebuild though. Dan but if you want to take a stab, i'm quite happy to provide a spare valve and a 6.9 for the purpose of that experiment :-)

Euro W126's with full SLS share the same valves shocks and rear accumulators as the 6.9. W126 cars with only rear SLS have a different set up.