Repairing the Headlamp Wiper Motor
Pete's
Note...The Headlamp wiper
motors seem to be a fairly common failure item in the W140. Don't fret,
replacing the wiper motor isn't difficult.
This article describes the procedure for the front right (when sitting in the car) assembly in a 1992 500SEL.
I am fairly confident this procedure will work for all W140 Sedans.
An article written and kindly provided by Clifford T Floeck, III
| Remove plastic cover behind headlight and in front of radiator surge tank. Push the retaining tabs towards the front of the car, and pull the cover up and out. |
|
| Cover removed. Back panel on headlight assembly visible. |
|
| Remove Phillips screw at the inside end of the filler panel between the headlight assembly and the bright trim on top of the bumper cover. |  |
| Carefully pry and flip the cover revealing the end of the windshield wiper motor arm and remove attaching nut. As noted in another job description, be aware that your particular car may require some penetrating agent to allow removal. This car was Dallas, TX bought and driven for it's entire life, so none was required. |  |
| Pete's note...for
those of you living where salt is used, this cover may be stuck on
tight...
Using a large flat blade screwdriver and thick rag, pry the cover away from the attachment point. |
|
| Nut loosened. Note the hollow shaft of the wiper motor arm. Washer fluid is pumped through it. |  |
| Carefully detach and move trim filler panel. |  |
| Detail of turn signal retaining clip. Use caution when releasing as the plastic can become brittle and break. |  |
| Pete's note...Reach into the opening where the cover was, and disengage the spring clip holding the corner lamp assembly in place. | 
|
| Remove upper mounting screw located in radiator core support, just in front of air intake silencer. |  |
| Turn signal removed. Headlight still in place. Note wiper motor shaft below headlight assembly. |  |
| These are the outer retaining screws for the headlight assembly. Remove carefully. |  |
| Note that screw is not visible from any position above level. |  |
| This in one of two inner attaching screws. The tube is the filler neck for the washer bottle. Headlight assembly is to your left, radiator is to the immediate right. |  |
| Second inner attaching screw (small one). |  |
| Move headlight assembly forward and carefully unplug headlight unit power cable. |  |
| Disconnect headlight power cable from the lower portion of the headlight assembly. |  |
| Carefully remove fluid hose from wiper motor assembly. Note that the hose on this car had discolored with age, and become hard. A very small portion can be trimmed away to bring fresher, more flexible hose in to play for reattachment during reassembly. |  |
| Headlight assembly removed, showing cavity in front fender. |  |
| These are the two wiper motor attaching screw on the bottom of the removed headlight assembly. Remove motor. |  |
| New motor installed on headlight held in vertical position. Power connection is also visible. Be sure to re-install all power cables. Don't miss any/one. Notice the "L" shaped nipple opposite the drive shaft. That is the washer fluid hose connection. |  |
| Reinstall the now assembled headlight and wiper motor unit. Use care in maintaining clearance with plastic fan grilles. |  |
| Headlight repositioned
for securing. Check fit and alignment before final fastener tightening.
Reinstall trim filler panel, then turn on headlights and run wipers and washers through two cycles minimum to assure wiper drive arm is in the "parked" position before reinstalling wiper arm. Do not stand in front of wiper motor during this operation. Align wiper arm, press in to proper position, then install retaining nut and tighten retaining nut securely, and flip cover back in to position. Reinstall all other hardware. |
 |
| Wipe off all the smudges and finger prints, clean and place tools back in tool box, and declare, "Job done!" | |
Thanks go to Clifford T Floeck, III for this fine article!
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