Replacement: front lower arm – Mercedes W203. AUTODOC recommends:
The replacement procedure is identical for the left and right lower control arms.
Please note: all work on the car – Mercedes W203 – should be done with the engine switched off.
Carry out replacement in the following order:
Step 1
Secure the wheels with chocks.
Step 2
Loosen the wheel mounting bolts. Use wheel impact socket #17.
Step 3
Raise the front of the car and secure on supports.
Step 4
Unscrew the wheel bolts.
AUTODOC recommends:
Warning! To avoid injury, hold the wheel while unscrewing the fastening bolts. Mercedes W203
Step 5
Remove the wheel.
Step 6
Undo the fasteners of the oil pan lower cover. Use a drive socket #8. Use a ratchet wrench.
Step 7
Remove the oil pan cover.
Step 8
Clean all joints of the arm. Use a wire brush. Use WD-40 spray.
AUTODOC recommends:
Replacement: front lower arm – Mercedes W203. After applying the spray, wait a few minutes.
Step 9
Unscrew the fastener connecting the control arm to the subframe. Use a combination spanner #21. Use a drive socket #21. Use a ratchet wrench.
Step 10
Clean all joints of the arm. Use a wire brush. Use WD-40 spray.
AUTODOC recommends:
Replacement: front lower arm – Mercedes W203. After applying the spray, wait a few minutes.
Step 11
Unscrew the fastener connecting the ball joint to the steering knuckle. Use a combination spanner #21.
Step 12
Disconnect the ball joint from the steering knuckle. Use a ball joint puller.
Step 13
Remove the fastening bolt.
Step 14
Remove the arm.
Step 15
Clean the mounting seats and the thread of the suspension arm. Use a wire brush. Use WD-40 spray.
Step 16
Install a new arm.
Replacement: front lower arm – Mercedes W203. Professionals recommend:
During the installation process, use only new bolts and nuts.Do not damage the ball joint cover.
Step 17
Install the fastening bolt.
Step 18
Connect the ball joint to the steering knuckle.
Step 19
Screw the fastener connecting the ball joint to the steering knuckle. Use a combination spanner #22.
Step 20
Support the arm. Use a hydraulic transmission jack.
Step 21
Screw the fastener connecting the control arm to the subframe. Use a combination spanner #21. Use a drive socket #21. Use a ratchet wrench.
Step 22
Tighten the rear fastener connecting the arm to the body subframe. Use a combination spanner #21. Use a drive socket #21. Use a torque wrench. Tighten it to 80 Nm torque.+120°
AUTODOC recommends:
Important! Be sure to use new fasteners.
Step 23
Tighten the ball joint fastener. Use a combination spanner #22. Use a torque wrench. Tighten it to 50 Nm torque.+60°
AUTODOC recommends:
Important! Be sure to use new fasteners.
Step 24
Remove the support from under the arm.
AUTODOC recommends:
Replacement: front lower arm – Mercedes W203. Lower the transmission jack smoothly, without jerks, to avoid damaging components and mechanisms.
Step 25
Treat all joints of the arm. Use copper grease.
Step 26
Reinstall the oil pan lower cover.
Step 27
Tighten the fasteners of the oil pan lower cover. Use a drive socket #8. Use a ratchet wrench.
Step 28
Treat the surface where the brake disc contacts the wheel rim. Use copper grease.
Step 29
Clean the brake disk surface. Use a brake cleaner.
AUTODOC recommends:
Replacement: front lower arm – Mercedes W203. After applying the spray, wait a few minutes.
Step 30
Install the wheel.
AUTODOC recommends:
Warning! To avoid injury, hold the wheel while screwing in the fastening bolts on the car. Mercedes W203
Step 31
Screw in the wheel bolts. Use wheel impact socket #17.
Step 32
Lower the car and working in a cross order, tighten the wheel bolts. Use wheel impact socket #17. Use a torque wrench. Tighten it to 110 Nm torque.
Step 33
Remove the jacks and chocks.
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