My 6.9 has been on a lft for 8 months waiting for a recon gearbox. Suspension was locked in position 1.The gearbox went in last week but now that the car is back on the ground the suspension will not come up, even after running for an hour. Does anyone know what's wrong?

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'66 W100 600 SWB
'05 W463 G55K AMG
'91 W126 500SEL
'93 W463 300GDL
'84 W460 280GES
'83 W460 300GDL
'66 W111 220SEb Coupe
'58 W121 190
'58 W180 220S
Have previously owned '99 SL600, '99 ML320, '79 450SLC, '79 450SEL 6.9 x 2, '68 600, '91 190E 1.8, '90 190E 2.0, '85 190, '90 500SL, '92 500SEL, '97 E300Turbodiesel, '91 300D, '72 280S, '82 300D, '81 300SD, '85 230E, '56 220a and I'm sure I'm forgetting some.

Position 1 meaning the lever is fully depressed and set to self levelling? Perhaps the levelling valves are stuck? Hopefully Gerryvz or another M-100 owner will see this post.

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1974 240D 3.0L 4(M) - 250K -OM617.910 + 300D FW + Rajay turbo power!
1977 6.9 3(A) - 84k

Sorry. on the lift it was at the first stop out (locked) as opposed to second stop out (raise). That's how it's been for 8 months. Now we've pushed it back in to normal/self-leveling engine running and it's sitting down.

that model should have hydraulic suspension, not air, we had one like that in the shop, turned out the control valve near the radiator was partially plugged, we ended up replacing the vale per the customers request, but tapping it with a brass hammer allowed the obstruction to pass.

I think it's called "hydropneumatic" which is a combination of oil and air. Anyway, it's still on the ground. Please help.

With the dash knob pushed all the way in (also make sure under the hood, that the disk [cable operated] on top of the fluid reservoir is against the 'stop') rev the engine to 2500 or more for a few minutes.

Assuming everything was in good order when it was put up, it ought to return to proper ride height.

Every time I get the tires rotated, the car drops and it takes a bit of constant revving to get the pressure up.

I assume the fluid level is correct. Don't over fill it.

tell us about the air part

bet he means nitrogen

Full explanation and diagrams at www.m100.cc It is a combination of hydraulic oil (hydro-) and compressed air (-pneumatic). Ok?

Regards.

__________________
'66 W100 600 SWB
'05 W463 G55K AMG
'91 W126 500SEL
'93 W463 300GDL
'84 W460 280GES
'83 W460 300GDL
'66 W111 220SEb Coupe
'58 W121 190
'58 W180 220S
Have previously owned '99 SL600, '99 ML320, '79 450SLC, '79 450SEL 6.9 x 2, '68 600, '91 190E 1.8, '90 190E 2.0, '85 190, '90 500SL, '92 500SEL, '97 E300Turbodiesel, '91 300D, '72 280S, '82 300D, '81 300SD, '85 230E, '56 220a and I'm sure I'm forgetting some.

did you try revving it up?

the link you provided isn't any good, i have worked on several of these and have never noticed anything with air, other than the nitrogen in the accumulators, not trying to be a smart ass, just thought there might be someting i missed.

Apologies. Correct address is www.m-100.cc
Let me know what you think. For now we'll just tap everything we can see with a light hammer and see what happens.

Eddie, any luck with the suspension? I checked on my 6.9 yesterday and found the rear suspension came completely down. I started up the car and nothing happened in position 1 (lever pushed in). Even after driving it around at low speeds in the parking structure nothing happened. The thing that finally got the car back up and level was pulling the lever to position 3 (all the way out). Check the switch and cable on top of the reservoir to make sure it hasn't slipped. That got the suspension back up.

Let us know how it turns out.

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1974 240D 3.0L 4(M) - 250K -OM617.910 + 300D FW + Rajay turbo power!
1977 6.9 3(A) - 84k

No air in the system. Nitrogen spheres and hydraulic struts are used in place of the springs/shocks on a regular car. There is no compressed air. The compressed N2 in the spehres is sealed.

Pneumatic refers to a gas, not air specifically.

Run at fast idle and see if it comes up. If not, you might need to check output pressure of the pump.

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MB-less

But at least it LOOKS sooo cool siten on da ground!