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Subject Fabricated Window Lift Brackets (replace broken OEM plastic)
     
Posted by 300zx90 on April 25, 2005 at 7:25 PM
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Message Note: This post is an update to my previous writeup. Several users requested more details regarding the actual fabrication of the brackets, so I made a second set and took pictures along the way. If you read the other post you can skip to the fabrication section.

Summary of the Problem
The other weekend I went to lower the passenger-side window only to hear a "pop" and watch the window slide down into the door on its own :( After removing the door panel I found that both of the plastic brackets, which are bonded to the bottom of the window, had broken. This picture shows where the brackets attach to the glass:

Here are a few pics of the broken brackets:

After calling Coz I was informed that these brackets are non-replacable and I was looking at $220 for a replacement window. At the advice of Coz, I made my own.

Fabrication
Tools Required:


  1. Sawzall, hacksaw, chopsaw, or some other means of cutting steel angle iron
  2. Drill press (hand drill would work too)
  3. Bench vice
  4. Welder
  5. Grinder
  6. Clamp (vice-grip works)

Materials Required:

  1. 1" steel angle
  2. 2X each of 1/4-20 flat-head fastener, 1/4" flat washer, and nylok nut
  3. One non-locking 1/4-20 nut
  4. Flat washers or shim stack slightly thicker than the window glass thickness
  5. 1" wide, 1/8" thick steel flat stock

Step One: Cut two pieces of 1" angle at a length of 1-3/8".

Step Two: Drill a 1/4" hole in the center of one flange of the angle. I also chose to add a few smaller holes to aid curing of the adhesive.

Step Three: Countersink the interior edge of the 1/4" hole. I didn't have a countersink tool handy so I simply used a larger drill bit.

Step Four: Insert the fastener into the 1/4" hole, from the countersink side, and secure it with a non-locking nut and a washer. The nut and washer position the fastener perpendicular to the face of the angle.

Step Five: Weld the fastener head to the angle. I used a bench vice to hold it while I welded it.

Steps Six, Seven, and Eight: Grind the weld flush with the inner face of the angle. Cut a piece of 1" flat stock that is 1-3/8" in length which will serve as the opposite flange to complete the channel. Mark where you will trim the bottom flange of the angle using a spacer and the piece of flat stock. For the spacer, I used a pair of flat washers which combined for a thickness slightly greater than the window glass thickness.

Step Nine: After trimming the angle, use a clamp to position the piece of flat stock for welding. In this picture you can see the two washers that I used as a spacer, and you can see the seam that needs to be welded to join the piece of flat stock to the angle.

Step Ten (optional): Grind the weld from Step Nine to produce a clean finish. This isn't required, although it reduces the risk of snagging anything inside the door.

Step Eleven (optional): As in Step Two, I chose to add holes to the back flange of the channed to aid curing of the adhesive. If you drill using the existing holes on the front flange as a guide you can avoid filing the interior of the channel as the drill bit will produce burrs on the outside face only. It's easy to clean the burrs on the outside, but if you were to drill from outside-in you would need to file the internal burrs. I encountered this on the first set when I drilled thru both faces at the same time, but the second time around I did each face as a separate step as shown in this writeup. It's your call if you want to include any "breather" holes at all. The OEM brackets don't have this, but they do have a textured inner surface to improve the bond. This picture also shows the 1/4" washer and nylok nut which are used to secure the bracket to the window lift mechanism (install the bracket stud thru the hole in the lift mechanism and secure it with the nut and washer. This will make sense after removing the original bracket).

Finished Product:
Test fit the brackets to the glass and file the interior as needed so the glass fits all the way to the base of the channel. Then add a coat of paint and you're done.

A comparison of the old plastic version and the new steel version:

And finally a pic of the new bracket on the window (not bonded yet):

Installation: There are probably a few ways to skin this cat, but this is the way I did it. I first attached the brackets to the lift mechanism and filled each bracket with adhesive (I used aquarium sealant aka silicone), then I lowered the glass into the brackets. I then raised the window completely using the window motor until the window was all the way up. With the window contacting its hardstops and the motor pushing the lift mechanism up against the bottom of the glass the brackets are secured nicely for curing. I let mine cure for three days (out of town on a business trip so that was conveninent) before trying to lower the window. Worked great for me, so hopefully this writeup will help others.

Are these available for purchase?
No, this writeup is a guide only and simply illustrates how I made these to fix my window. I am not available to produce these for resale, so if you are unable to duplicate the steps detailed above then print this out and contact a local fabrication shop/buddy. If you want to base a product on these, knock yourself out. :)

________________________________________
NA to TT, starting from the ground up...

     
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