Cars / e32 / Body & Interior / Replacing a Window Regulator Gear

Replacing a Window Regulator Gear

Article by: Shayne McGuire

Article applies to: All e32 and e34 models.

Not a hard job. Much better than drilling out rivets and replacing the complete motor when there is nothing wrong with it.

Symptoms are a jammed window but you can still hear ‘clicking’ in the door and/or there is a terrible ratcheting noise from the door but the window won’t move and/or you hear the motor run but the window doesn’t move.

If the window is stuck in the open or partially open position and you need to close it you will need to remove the door panel. To remove the door panel you need a precision standard, T20, and Phillips screwdrivers. You can find instructions to remove the door panel here:

Following the above instructions you do not need to remove the door tweeter and, although implied, the instructions neglect the T20 screw inside the cover under the door latch pocket.

Once the panel is off you need to use a large screwdriver or the lug wrench or? to force the large rack gear down and back while using the window switch to assist in getting the glass back up.

Now for replacing the gear. I bought the part here and it is of excellent quality and was shipped very fast:

Once you have the panel off you will need the following tools:

  • two number 8 screws and a screwdriver
  • a standard screwdriver
  • two pairs of locking pliers
  • a hammer
  • a punch
  • a small socket
  • some grease
  • some form of glue

Use the standard screwdriver to pop the cover off of the gearbox:

Once the gear is exposed:

Insert two #8 sheet metals screws in the opposing holes thus:

Lock a pair of locking pliers (Vice Grips) on each screw and start rocking the assembly out and off of the shaft.

It can take a couple of minutes.

Use force but not enough to pull the whole assembly apart.

Once the retainer mount is off you can remove the exposed gear. You nay need to use locking pliers to pull it out of the housing.

Clean any detritus from inside the housing:

Lubricate the worm gear. I use silicone grease because it is inert to rubber and plastics:

Install the dampers into the gear and then install the retainer/lock ring:

You must assemble the gear first as above because it needs to be oriented correctly over the shaft when you insert it into the housing.
Insert the gear into the housing over the shaft:

Use a small socket over the shaft and tap with a hammer to begin locking it in place:

Once it is retained use the hammer and punch to press it to the correct depth on the shaft:

Use a plastic adhesive or a product like ‘Automotive Goop’ to reinstall the gear box cover:

Test the window a few times then install the vapor barrier and door panel.

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