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C-3271
ARNOTT COIL SPRING CONVERSION KIT
FOR MERCEDES-BENZ S550 (W221)
The air suspension system is under pressure (up to 10 bar, or 150 lbf/in). Verify pressure has been relieved and disconnect power to the air suspension system prior to disassembly. Do not allow dirt or grease to enter the system. Always wear standard hand, ear, and eye protection when servicing the air suspension system.
Reading this manual signifies your agreement to the terms of the general release, waiver of liability, and hold harmless agreement, the full text of which is available at
Not to be stored below 5°F (-15°C) or above 122°F (50°C).
Avoid damage to air lines and cables.
Removal and installation is only to be performed by fully qualified personnel.
Use car manufacturer’s diagnostic software.
Damage to the vehicle and air suspension system can be incurred if work is carried out in a manner other than specified
in the instructions or in a different sequence.
To avoid the possibility of short circuits while working with electric components consult your owner's manual on how to
disconnect your battery.
Consult your vehicle owner's manual, service manual, or car dealer for the correct jacking points on your vehicle and for
additional care, safety and maintenance instructions. Under no circumstances should any work be completed underneath
the vehicle if it is not adequately supported, as serious injuries and death can occur.
1. Set steering to straight ahead.
2. Remove applicable front wheel. (FIGURES 1, 2)
3. Remove airline and three (3) upper mount nuts. (FIGURES 3, 4)
4. Locate the air strut’s electrical connector and remove retaining clip. (FIGURE 5)
5. Disconnect and separate the two (2) electrical connectors. (FIGURES 6, 7)
6. Cut cable ties and remove brake line bracket and bottom clip. (FIGURES 8, 9, 10, 11)
7. Locate and loosen lower mount set screws. (FIGURE 12)
8. Loosen upper control arm nut. (FIGURE 13)
9. Separate the upper control arm from the spindle assembly. (FIGURES 14, 15)
10. Pull down on the spindle assembly and remove the air strut from the vehicle. (FIGURES 16, 17)
FRONT COIL STRUT INSTALLATION
Tighten all nuts and bolts to manufacturer's specifications during the installation process.
1. Install front coil strut onto vehicle. (FIGURE 18)
2. Seat the coil strut onto the lower ball joint and tighten the lower set screws. (FIGURES 19, 20)
3. Reinstall the upper control arm nut and tighten to manufacturer specifications. (FIGURES 21, 22)
4. Reinstall the brake line holder and secure it with the supplied cable tie. (FIGURES 23, 24, 25, 26)
5. Install the upper mounting nuts. (FIGURES 27, 28)
1. Set steering to straight ahead.
2. Lift vehicle and remove the rear wheels. (FIGURE 29)
3. Remove the brake caliper retaining clip. (FIGURE 30)
4. Disconnect and remove the brake pad wear sensor. Remove the two (2) bolts holding the brake caliper. Remove the brake caliper and suspend to prevent damage to brake lines. (FIGURES 31, 32)
5. Remove the fasteners and inner wheel liner to expose the rear air strut’s wiring block. (FIGURES 33, 34)
6. Remove the metal clip and plug for the rear air strut’s dampening coil. (FIGURES 35, 36)
7. Remove the lower sway bar end link nut and separate. (FIGURE 37)
8. Remove the lower air strut mounting nut. (FIGURE 38)
9. Remove the lower control arm nut. (FIGURE 39)
10. Remove the rear dash cover from inside of the vehicle. (FIGURE 40)
11. Pull back the foam insulation to expose the air strut top mount. (FIGURE 41)
12. Remove the air line. (FIGURES 42, 43)
13. Remove the three (3) top mounting nuts. (FIGURE 44)
14. Remove the lower control arm bolt and the lower air strut mounting bolt. (FIGURE 45)
15. Pull down on the lower control arm and remove the air strut from the vehicle. (FIGURE 46)
REAR COIL STRUT INSTALLATION
Tighten all nuts and bolts to manufacturer's specifications during the installation process.
1. Install coil strut onto vehicle. (FIGURE 47)
2. Reinstall the lower strut mounting nut and bolt and tighten to manufacturer specifications. (FIGURES 48, 49)
3. Raise the lower control arm and reinstall the mounting nut and bolt and tighten to manufacturer specifications. (FIGURES 50, 51)
4. Reinstall the sway bar end-links and tighten to manufacturer specifications. (FIGURES 52, 53)
5. Reattach brake caliper and bolt into place. (FIGURES 54, 55, 56)
6. On the right rear, reattach brake sensor and plug in. (FIGURES 57, 58, 59, 60)
7. Reinstall the inner wheel well liner. (FIGURE 61)
8. Reinstall the brake caliper retaining clip. (FIGURE 62)
9. Secure the three (3) top mounting nuts. (FIGURE 63)
10. Repack foam, air line remains disconnected. (FIGURE 64)
11. Replace rear deck lid. (FIGURE 65)
1. Remove passenger side floor mat to access the kick plate. (FIGURES 66, 67)
2. Loosen and remove the (3) fasteners, then lay the kick plate down on the floor board to expose the vehicles air suspension control module. (FIGURE 68, 69)
3. Unplug the module from the vehicle and install the EBM using the supplied hardware and wiring diagram. (FIGURES 70, 71)
4. Splice wires using wiring diagram in step 5. (FIGURES 72, 73, 74)
Electronic Bypass Module
From
To
Vehicle's Wiring Harness
Yellow
Two Pin Connector (Pin 24)
Blue
Two Pin Connector (Pin 25)
Red
Red/White (Pin 47)
Black
Brown (Pin 21)
Leave air suspension control module disconnected.
6. Inside the engine compartment, open the fuse box and replace the below indicated fuse (#46) with the included fuse. (FIGURES 75, 76, 77, 78)
7. EBM installation complete.