You probably find yourself here because the front window in your Lexus ES350 isn’t working properly. You’ve probably discovered that one of the plastic clips that connects the window regulator to the window has broken. Maybe you have a different Lexus with the same problem.

Of course you aren’t alone. This has happened to a lot of people and will probably keep happening for as long as these cars are on the road.

My first product involves this now-infamous broken window clip. Here’s what I did to fix my father-in-law’s ES350, and what you can do to fix your Lexus window.

Here’s a summary of what I know about this problem based on my research and experience:

  • The earlier models of the 5th generation ES350 suffer from a chronic failure of the front-most plastic clip that joins the window regulator to the window
  • This seems to affect the first two to three model years of ES350 (2007-2009)
  • The only proper solution so far has been to buy a whole new window from the dealer, which comes with new clips pre-adhered to the glass – expensive and usually outside of warranty coverage

My father-in-law and I went through the process of reporting the problem to the Lexus dealer, and attempting to negotiate a free or discounted repair. They agreed to fix the problem for the retail price of the window (sparing us the labor charge). This was still going to cost ~$400 and we thought we could do as good of a job for less $$$.

So why does this part fail? Well not surprisingly, I believe it can be traced back to the design of the part. Take a look at the pictures below:

Broken window clip with red arrow

First, you’ll notice that the point of failure, at least on this part, is a very thin section at the bottom of the U. This makes sense..there’s absolutely no reinforcement in that area…it’s very thin.

I believe that since the ES350 window is curved, and travels on a curved path, and because the window regulator is straight, and travels up and down quite linearly, that at the extremes of the window’s travel, there are very slight lateral forces being applied to the clip. The part was never designed to handle these types of forces repeatedly.

That, combined with thermal cycling of a fairly extreme nature (depending on where you live) and the rate at which the passenger window is actually cycled up and down, leads to a failure of the plastic part.

Failure 1

You could argue circularly for hours about whether the motion design or the part design is the true root cause. But, since the motion design would be very difficult to overcome, and the part design fairly easy to overcome, the burden of fault lies with the part. It’s just weak. We know from Lexus TSB L-SB-003-09 that ultimately, the manufacturer came to the same conclusion and redesigned the clip on later models of ES350.

I haven’t seen the redesigned part on the new Lexus windows, but it likely contains bracing or is thicker in the area highlighted by the red triangles in the illustration above.

Either way, if you find that your car is suffering from this failure, what are you going to do? Are you going to spend $400-$1000 on a new window from the dealer? Hopefully not. We took a different path, and now so can you.

I decided to leverage my design, fabrication, and glass expertise and and just create a new clip from some fresh 6061 aluminum:

Original prototype part

Side-by-side comparison

Side by side comparison of original prototype clip and Lexus OEM

Another side-by-side

Grooves to increase surface area

Grooved to increase surface area – this mimics the design of the original part

The new part came out beautifully and I couldn’t wait to get it installed.

The first step was to remove the door panel and speaker. Once the door panel was removed I dropped the window regulator low enough to access the site of the broken clip. If you’d like a full set of instructions for removing the door panel just follow this link: II-1000 Window Clip Replacement Rev 002

Window and regulator arm

I had already removed the old clip to use for prototyping. The next task was to remove the old adhesive. This is a fairly soft rubberized adhesive (more on that in a bit) so it scrapes off very easily using a fresh razor blade:

Cleaning adhesive off the window

I did my best to get the area as clean as possible. It’s tough to reach some spots. Once I removed as much of the adhesive as I thought I could, I wiped the surface with isopropyl alcohol (you could use acetone or equivalent solvent):

After wiping with alcohol

Once the area was clean I gave the part a test fit:

Test fit in the car

Looks great and it kind of clips right into place. It’s obvious that the fitment is perfect.

Then I removed the part and filled the gap full of adhesive. I spent a LONG time selecting an adhesive for this and finally settled on a 3M Urethane-based windshield adhesive for a number of reasons:

  • This adhesive is designed specifically for adhering glass to coated and uncoated metal substrates – perfect – that’s exactly what we’re doing
  • The adhesive in this application acts as both a damper and as a bonding agent, securing the part to the glass and absorbing vibratory forces transferred through the vehicle frame to the door and to the regulator so it needs to be thick and rubbery
  • The adhesive should have a fairly short work time and a high strength bond – this has an 15 minute work time and a 72 hour Lap Shear strength of 550psi

Our bondline is going to be thicker than that used for the lap shear test, which will reduce the overall strength of the bond a little bit, but the takeaway is that this is a tough application-specific adhesive.

The adhesive I used is 3M part number 08693 and is available off the shelf at O’Reilly/Autozone/Pepboys/et al for about $15. I used less than an ounce of it. My kits come with one 0.5 ounce tube per part.

MAJOR NOTE: WEAR RUBBER GLOVES – just touching this adhesive spreads it around like wildfire and it makes a mess. It contains black carbon powder which is just really messy.

Filling the joint gap with 3M adhesive

Once the entire gap is filled in with adhesive, I used one finger to press the regulator arm backward to make space, and using the other hand, slid the clip up onto the glass in the approximate location. Let the regulator arm come forward to its natural position, then move the clip into place centered over the bolt hole:

Final installation of clip

A lot of adhesive will be forced out. This is good. This is exactly what the factory job looked like. in this case, more is better!

I smeared a little extra on and around the part just as a precaution. It looks messy but that’s okay! Nobody’s going to see it anyway:

Bolted in place

The only thing left to do was wait for it to cure then test it and put it all back together. I waited way past the actual cure time of the adhesive and went for about 60 hours before testing. The window operates totally smoothly with no noise at all. I call this a tremendous success.

Click here to purchase the complete repair kit. I now offer multi-part discounts and forward/rearward clips as well.

If you have any questions send an email right to my personal phone: