Saturday, October 13th 2018


Removal, Repair and Reinstallation of the 356C Window Regulator
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Removal, Repair and Reinstallation of the 356C Window Regulator


September 24, 2010 |
Troubleshooting & Repair

Text and photos by Mark W. Sabbann

The window regulator basically consists of a panel piece, two regulator arms, a partial ring gear and the spring assist assembly. See photos 1 and 2 below.

The panel piece:

  • Fastens to the inner door with four 10mm ATF hex head bolts
  • Houses the pinion gear attached to the splined window handle shaft. The pinion gear drives the partial ring gear to provide the lifting movement.
  • Supports the spring assist assembly.
  • Is riveted to the lower regulator arm and allows it to pivot

The upper regulator arm consists of:

  • One straight regulator arm and one partial ring gear piece riveted together.
  • The straight regulator arm is press-fit to the flats on the spring pivot pin.
  • The partial ring gear pivots around the spring pivot pin between the regulator arm and the panel piece.

The ‘T’ shaped support link:

  • Supports the window.
  • Has two guide pins with spring loaded washers that slide in a channel at the base of the window.
  • Is riveted to the upper regulator arm.
  • Is bolted to the lower regulator arm by a removable pivot pin, keyed washer and 13mm ATF nut assembly.
  • Has a stop block for adjusting travel limit

The spring assist assembly:

  • Includes a flat bar coil spring
  • Includes a pivot pin with a slotted head and two flats at the other end. There is a small hole in the end of the pin but it’s function is unknown.
  • The inner end of the spring locks into the slotted head of the pivot pin.
  • The outer end of the spring fits over the tab protruding from the panel piece.



Door Panel Removal

  1. Note that with the window fully closed, the window handle is in a 4 o’clock or 8 o’clock position depending on which door is being repaired. When the window is fully open, this puts the handle at a 3 o’clock or 9 o’clock position, aligned with the armrest and clear of the driver’s legs.
  2. Compress the escutcheon plate against the coil spring sitting behind the fabric of the inside door panel.
  3. While holding the escutcheon plate away from the back of the window handle, drive the retaining pin out with a 3mm/1/8″ straight punch. Remove the window handle and retain the escutcheon plate and locking pin. Repeat for the lock handle. Use caution to avoid abrading the door panel fabric with the punch and hammer.
  4. With both handles removed, the coil springs around each handle post will be pushing on the back of the panel fabric.
  5. Remove the Phillips screws holding the top rail to the door. Lift the top rail upwards slightly to clear the door.
  6. Remove the Phillips screws holding the inside door panel to the door.
  7. Grasp the panel by the armrest and one edge and remove it by gently lifting up and out. Pulling out will be trying to clear the window crank and lock handle posts, and pulling up will be trying to separate the two metal clips behind the armrest from the mating slots in the metal door panel.
  8. Remove the two coil springs from the crank posts. Note which spring fits over which post as they may have a different diameter at the small end. (Mine did.) The 356 Shop Manual indicates that there is some sort of foam piece that evidently slides over the two shafts. (Mine were missing)

Window Regulator Removal

  1. Temporarily re-install the window handle crank on the splined crank post and lower the window part way down. Move it into a position so that the removable pivot pin on the regulator arms below the center of the window is easily accessible through the large opening.
  2. Remove the pivot pin nut from the back side and associated hardware from the regulator. The hardware from door inside to outside will include the pivot pin, a thin washer with a larger inner diameter that fits tight behind the pin head, another washer with a slightly smaller inner diameter that fits between the two regulator arms, a keyed washer that fits into a slot on the outermost of the two regulator arms, a star lock washer and the 13mm ATF nut.
  3. Removal of this pin will free the two linkages and allow you to manipulate the ‘T’ shaped regulator link that slides in the channel at the bottom of the window glass. Let the lower arm drop to the bottom of the door or move it out of the way as necessary.
  4. With one hand supporting the window glass and another on the window handle, crank the window up or down as the two guide pins in the ‘T’ shaped regulator link move right or left guided in the lower window channel. Move the regulator until the rear guide pin is in a position to clear the channel, and gently pop it out of the channel. Continue supporting the glass and adjusting the regulator with the window handle until the front guide pin clears the channel and gently pop it out. The 356 Shop Manual suggests bending the channel edges slightly to facilitate removal of the guide pin. This is hard to do and I suggest that it be avoided if possible. The channel is a fairly heavy gauge of metal and it is directly attached to the glass. Attempting to bend it adds unnecessary stress to the glass.
  5. With the window free from the regulator, slide it upwards into the ‘closed’ position. The felt guide strips should provide enough friction to hold the window in place. If not, a piece of wood of the proper length can be cut to fit inside the door to hold the window up. The intent is to allow clear access for removal of the window regulator.
  6. Remove the window crank handle from the handle post. With a 10mm ATF socket or wrench, remove the four bolts and washers holding the regulator to the inside of the door. Hold the regulator with one hand as the last bolt comes out and move it back and away from the inside metal panel.
  7. Remove the complete regulator from inside the door. The window handle may need to be temporarily re-installed and used to move the regulator arms such that the overall length and width of the regulator will fit through the largest opening in the inner metal door panel. The regulator will also have to clear the space between the outer door skin and the front window guide track which is bolted to the door bottom.

Window Regulator Cleaning and Lubrication

  1. Examine the regulator for wear and remove excess old grease and dirt. The pinion gear is not easily removable so clean it and apply new grease. Try to get some grease onto the pinion shaft.
  2. Wipe the regulator down with a light oil to prevent rust.
  3. Examine the two guide pins and washers attached to the ‘T’ shaped link for excessive wear. Clean and re-grease.
  4. If the regulator arm/ring gear assembly has come off of the spring pivot pin, clean and re-grease and re-install the thin washer that goes between the two links.
  5. The upper regulator arm should fit tight onto the flats of the spring pivot pin. With one hand on the upper regulator arm and a screwdriver in the slot of the spring pivot pin, rotate the pin and align the arm onto the flats of the pin and press together. A rubber mallet may help if the fit is tight. Do not install the coil spring yet.
  6. Once assembled, the spring pivot pin can be slightly peened to tighten the fit to the regulator arm.
  7. Clean and re-grease the two riveted connections.
  8. Temporarily re-install the lower pin and keyed washer assembly and window crank and run the regulator up and down checking for binding or interferences.
  9. With the regulator in the ‘up’ or ‘closed’ position, the spring pivot pin slot should be aligned with the linkage (see photo 3 below).
  10. Take the coil spring on it’s side and drop the hooked end over the tab in the panel piece. With a square jaw pliers, grip about half of the width of the center end of the flat stock spring, enough to get a good grip, but also leaving enough for alignment into the pivot pin slot. Twist the spring counter-clockwise over the pivot pin and when the spring and slot are aligned, force the spring down into the slot. Tap it flush with a rubber mallet.


Regulator Re-installation

  1. Prior to re-installation, apply some grease into the lower window channel where the guide pins slide. It is easier to do this with the regulator outside of the door, before the channel becomes less accessible. Return the window to the up and closed position.
  2. Remove and apply grease to the lower pin and keyed washer assembly but do not re-install it yet. It will be installed last.
  3. Use the window crank to move the regulator into roughly a horizontal position below the window. The lower linkage arm will be hanging down loosely.
  4. Thread the regulator through the larger door opening, between the guide track and the outer door skin. With the regulator in the forward door cavity, align the regulator arms between the window track and the inside door panel and move it towards the back door cavity. Adjust the position until the window crank shaft aligns with, and protrudes through the hole in the door. Align the holes and install the 10mm ATF bolts and washers to secure the regulator to the door.
  5. Use the window crank to adjust the regulator position, and move the window up or down by hand to get the guide pins aligned with the channel below the glass. Although the rear guide pin is more accessible, it seemed to work a little better to put it into the track first and then manipulate everything else to get the front pin into the track. It may take some fine coordination to do this. This is where the Shop Manual suggests bending the track to facilitate getting the pins into the track. This is more difficult than it sounds so do what you can in terms of getting the pin into the track to avoid this.
  6. With both guide pins in the channel, adjust the regulator and window so that the lower linkage and the ‘T’ link holes are aligned. Insert the pivot pin, various washers, the keyed washer and only partially tighten the nut. Raise the window to the closed position and make sure that the top edge is fully ‘up’ at the front and back corners. Tighten the nut on the pin and keyed washer assembly.
  7. Run the regulator up and down and make sure it is not binding. Adjust as necessary. Unless there were problems with the travel of the window, the limit stop block should not have to be adjusted.


Door Panel Re-installation

  1. Re-install the door panel in reverse order of removal.
  2. Install the foam pieces over the window and lock handle posts. Mine were missing but I used a couple of layers of a thin closed-cell packaging material, cut to about a 2″ diameter shape and center-punched to fit over the posts.
  3. Insert the two coil springs over the window and lock handle posts. Remember which spring fits over which post as they may have a different diameter at the small end. (Mine did.) The springs didn’t want to stay in position by themselves so I ran some clear packaging tape across the bottom coil and stuck it to the door to hold the spring in place while installing the door panel.
  4. Grasp the panel by the armrest and one edge and roughly position it so that the upper lip in the panel will hang off the top of the door at the base of the window. Drop it down so the two metal clips behind the armrest fit into the mating slots in the metal door, at the same time trying to align the window crank and door lock handle posts with the holes in the door panel. The coil spring around each handle post will be pushing on the back of the panel fabric.
  5. Re-install the Phillips screws holding the inside door panel to the door.
  6. Position the top rail and install it down over the door panel. Re-install the Phillips screws holding the top rail to the door.
  7. Before the next step, fashion a temporary retaining pin out of a 6p nail. Bend it slightly to give yourself a handle. Deburr any sharp edges and dull the tip so the nail doesn’t damage the fabric/leather.
  8. Take one escutcheon plate and push it against the coil spring over the splined shaft. Position the window handle onto the shaft at the 4 o’clock or 8 o’clock position depending on which door is being repaired, and push the bent nail up from the bottom through the retaining pin hole in the handle. This will keep the handle in place and the escutcheon plate pushed back while your other two hands are positioning the retaining pin and operating the punch and hammer.
  9. Carefully start the retaining pin into the hole in the handle and finally drive it in with the straight punch. Allow the escutcheon plate to compress against the back of the handle. Repeat for the lock handle.
  10. Run the window up and down, clean the glass, hop in your 356 and drive. Celebrate a successful window regulator overhaul!

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