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Suspension Control Upgrades

Started by Mattr, 23 July 2022, 11:33 AM

Mattr

Hey Folks,

I was dragging blue out, yesterday, to prep for driving to our new property, and I realized that I do greatly like the look of the car completely slammed. I don't, however, like the lever that is used for adjusting suspension height. Has anyone ever replaced this mechanism? I'm thinking maybe try and find a panel with three buttons to wire up that connect to a little servo or mechanism that adjusts the height: one that drops it completely, one that sets it to drive height, and one that sets it to max height.
1976 450SE 6.9 FrankenBenz (#2288?)
1977 450SEL 6.9 #2333

rumb

Those levers  (front and rear) dont just control height, it is also part of the suspension to control body roll and bumps. They are constantly changing as you drive.

The dash knob does control height, probably by changing system preasure. If you put a pressure regulator on that main line it might be able to lower overall system pressure, but at what ride quality I dont know.

If you built a tiny stepper motor screw link from the arm to the sway bar you could control it's length, and thus the height while keeping the rest of the system doing what it is suppose to do. A Raspberry Pi could control it.
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS
'21 E450 Cabrio

Mattr

Quote from: rumb on 23 July 2022, 12:48 PMThose levers  (front and rear) dont just control height, it is also part of the suspension to control body roll and bumps. They are constantly changing as you drive.

The dash knob does control height, probably by changing system preasure. If you put a pressure regulator on that main line it might be able to lower overall system pressure, but at what ride quality I dont know.

If you built a tiny stepper motor screw link from the arm to the sway bar you could control it's length, and thus the height while keeping the rest of the system doing what it is suppose to do. A Raspberry Pi could control it.

I was referring to the dash knob, rather than the blocks themselves. The dash knob, as far as I can tell, connects to a box in the front of the car via wire. Adjusting that lets you adjust the overall ride height for the vehicle.
1976 450SE 6.9 FrankenBenz (#2288?)
1977 450SEL 6.9 #2333

raueda1

Quote from: Mattr on 24 July 2022, 01:01 PM
Quote from: rumb on 23 July 2022, 12:48 PMThose levers  (front and rear) dont just control height, it is also part of the suspension to control body roll and bumps. They are constantly changing as you drive.

The dash knob does control height, probably by changing system preasure. If you put a pressure regulator on that main line it might be able to lower overall system pressure, but at what ride quality I dont know.

If you built a tiny stepper motor screw link from the arm to the sway bar you could control it's length, and thus the height while keeping the rest of the system doing what it is suppose to do. A Raspberry Pi could control it.

I was referring to the dash knob, rather than the blocks themselves. The dash knob, as far as I can tell, connects to a box in the front of the car via wire. Adjusting that lets you adjust the overall ride height for the vehicle.
Are you talking about replacing the dash knob mechanism with a solenoid control of some kind?  If so, it could certainly be done, but why?  I'm not sure what problem that solves.  The valve that the knob controls only has 4 discreet positions (one isn't available with the knob):  normal, high, locked and pressure dump (need to detach the cable from the control valve).  It doesn't "adjust" the height, it changes it from normal to high.  Nothing in between.
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

Mattr

Quote from: raueda1 on 26 July 2022, 02:54 PMAre you talking about replacing the dash knob mechanism with a solenoid control of some kind?  If so, it could certainly be done, but why?  I'm not sure what problem that solves.  The valve that the knob controls only has 4 discreet positions (one isn't available with the knob):  normal, high, locked and pressure dump (need to detach the cable from the control valve).  It doesn't "adjust" the height, it changes it from normal to high.  Nothing in between.

Then mine has either been tampered with, or maybe broken. As you pull the knob out? It raises up. If pushed all the way in, it's completely deflated. Pull it out, and it'll start raising up. There's no notch on it, so about halfway out is around ride-height, and fully out is max height.

After my interior replacement, the knob is hard to move, as it runs into the steering column. I was thinking a switch would be both convenient, and practical (it would be great to completely drop it for car shows).
1976 450SE 6.9 FrankenBenz (#2288?)
1977 450SEL 6.9 #2333

nathan

The knob controls three positions, normal ride height, locked suspension, and elevated ride.  its lowest setting should not be 'deflated', but standard ride height.  These Bowden cables are frustrating as with time they get sticky and dont work smoothly.  The cable runs to your front left engine bay where it attached to the master valve and controls the above positions.
1979 116 6.9 #6436
2018 213 e63
2011 212 e63
2011 463 g55
2007 211 e500 wagen
1995 124 e320 cabriolet
1983 460 300gd
1981 123 280te

rumb

#6
Sounds like the cable needs adjusting. Ride height should be with the knob pushed all the way in.
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS
'21 E450 Cabrio

daantjie

Indeed the switch has 3x clear detentes similar to an old school choke cable on a carburetor engine.

You should feel a distinct click for each setting which should then correspond to the correct disk position on the height control valve.
Daniel
1977 450 SEL 6.9 - Astralsilber

raueda1

And to add to all this, the end of the cable behind the knob is a small metal enclosure with the switch contacts.  It's capped with a phenolic/plastic/bakelite cover that's press-fitted into the enclosure.  It's not very durable, so after years of push/pull and wear the cover can become lose.  Then you get a wiggly knob, imprecise clicking and maybe an intermitent light. The whole thing can be removed and the enclosure tabs pressed back onto the cover.  It will then feel all nice and new and tight.  Removal is a huge amount of work though.  Cheers,
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

Mattr

Quote from: daantjie on 06 November 2022, 10:21 AMIndeed the switch has 3x clear detentes similar to an old school choke cable on a carburetor engine.

You should feel a distinct click for each setting which should then correspond to the correct disk position on the height control valve.
I definitely don't feel that. The rod on mine is completely smooth, and there's no feeling of clicks at any point. It just pulls out without any kind of sensation to it.
1976 450SE 6.9 FrankenBenz (#2288?)
1977 450SEL 6.9 #2333

raueda1

Quote from: Mattr on 22 January 2023, 09:09 PM
Quote from: daantjie on 06 November 2022, 10:21 AMIndeed the switch has 3x clear detentes similar to an old school choke cable on a carburetor engine.

You should feel a distinct click for each setting which should then correspond to the correct disk position on the height control valve.
I definitely don't feel that. The rod on mine is completely smooth, and there's no feeling of clicks at any point. It just pulls out without any kind of sensation to it.
Regardless of the clicks, does the suspension go up and down?  And does the dash light work?  Regardless, see my post above.
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

rumb

Here is a picture of the height knob showing the ball bearing that clicks into the holes on the side. Most definitely a solid click.
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS
'21 E450 Cabrio

Mattr

Quote from: raueda1 on 23 January 2023, 07:46 PMRegardless of the clicks, does the suspension go up and down?  And does the dash light work?  Regardless, see my post above.
Suspension goes up and down without issue. The 'adjustment' is off, because the PO liked the car to sit lower than stock, so fully depressed was ~2" lower than normal height (turning was barely possible, parallel parking would be impossible). Fully extended was a little higher than stock height. I tried to tune it back to what it should be, but didn't manage to get it right. I need to turn the car on, and adjust it up/down until it's correct, then reset the cable.
1976 450SE 6.9 FrankenBenz (#2288?)
1977 450SEL 6.9 #2333

raueda1

Quote from: Mattr on 24 January 2023, 10:41 PM
Quote from: raueda1 on 23 January 2023, 07:46 PMRegardless of the clicks, does the suspension go up and down?  And does the dash light work?  Regardless, see my post above.
Suspension goes up and down without issue. The 'adjustment' is off, because the PO liked the car to sit lower than stock, so fully depressed was ~2" lower than normal height (turning was barely possible, parallel parking would be impossible). Fully extended was a little higher than stock height. I tried to tune it back to what it should be, but didn't manage to get it right. I need to turn the car on, and adjust it up/down until it's correct, then reset the cable.
You "tune" ride height with the front and rear suspension valves, not the knob.  Search for ride height, much has been written.  You can easily see the rear valve under the back of the car.  Depending on model it may or may not be easy to see the front valve - maybe obscured by AC stuff.  Don't get under the car when adjusting!  good luck and cheers,
-Dave
Now:  1976 6.9 Euro, 2015 GL550
Before that:  1966 230S, 1964 220SE coupe, 1977 Carrera 3.0

rumb

This jpg has dimensions for setting ride height.
'68 250S
'77 6.9 Euro
'91 300SE,
'98 SL500
'14 CLS550,
'16 AMG GTS
'21 E450 Cabrio