Replacing 190E Steering Gearbox

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This article is a reference for replacing the steering gearbox on a 190E and may be applicable to similar models. Remanufactured steering gearboxes may be purchased from C & M Hydraulics based in Las Vegas, Nevada.


Time 2 hours
Cost $$$
Difficulty Medium
Parts required Power steering fluid - 1 46 0001
Power steering filter - 000 466 2104
Steering coupler - 123 460 0210
Renew locking hex nuts for tie rod ends - N913002010010
Applicable models All 190Es with left hand drive

Special Tools

Balljoint separator - Used for removing the left tie rod and center drag link

Gear puller - Removing pitman arm from steering gearbox output shaft

Suction gun - Used to remove old power steering fluid

Snap ring plier - Remove snap ring from pitman arm shaft

Power Steering Fluid


Part number 1 46 0001
Fill capacity 0.6 L
Cost (as of 12/2015) $8.70 / unit



  1. Lift front end of vehicle in the air

Siphon / Drain Old Fluid

  1. Remove power steering fluid reservoir cap
  2. Remove filter
    1. Filter is held in place by a 10mm nut under spring tension. Caution when removing this 10mm nut as it may spring out once unthreaded
  3. Pull old filter out with pliers
  4. Use a suction gun to remove old fluid.
    1. Rotate steering wheel left and right to pump more fluid back into the reservoir. Remove as much as possible.

Steering gearbox removal

  1. Center steering wheel and lock in place
  2. Remove power steering hoses
    1. Remove the hose closer to the engine via the 17mm nut
    2. Remove the hose farther away via hose clamp farther down the line
    3. You will be removing the steering gearbox with one hose left attached
  3. Looking up the steering shaft input, there should be a 6mm bolt visible for the steering coupler.
    1. A stubby 1/4" 6mm hex bit may be required to remove this
  4. Remove drag link and driver side tie rod from pitman arm
    1. 17mm nuts must be renewed
  5. Remove driver side wheel to access 3x 15mm frame bolts inside the wheel well
  6. Pull steering gearbox out with pitman arm attached
  7. Remove pitman arm on the bench
    1. Use snap ring plier to remove snap ring
    2. Use gear puller if necessary
    3. Take note on where the pitman arm is mounted on the output shaft. This affects front toe settings.


  1. Install upper power steering hose with 19mm nut onto the replacement steering gearbox
  2. Install pitman arm (this can be deferred to after the gearbox has been mounted in the car for easier gearbox installation)
    1. Use centering mark to align and install
    2. Tighten down at the same depth as previously measured
    3. Install snap ring
  3. Install steering coupler to steering shaft
    1. Note the flat end on the steering shaft when installing the new coupler. This is where the bolt runs through
  4. Install steering gearbox to coupler, do not turn steering wheel to install bolt yet
  5. Install the 3 frame bolts in wheel well
  6. Tighten power steering hoses
    1. 17mm hose nut
    2. Hose clamp
  7. Install tie rod and drag link
    1. Use new self locking hex nuts
  8. Turn steering wheel and install other 6mm coupler bolt
  9. Install power steering filter in reservoir
  10. Fill power steering reservoir to capacity
    1. Steering may need to be fully rotated a few times for correct fill