If you've acquired a 20 year old Lexus, congratulations! Your plastic door panels are probably cracked in every stress point and breaking apart from the door itself. Some may think that fixing door panels would be as easy us mixing up some resin, and pouring it to the cracks. Nope, resin does not stick to plastic. Even if you rough it up. Resin will simply peel off clean once its dry and cured. So what's the best and most cost effective way of fixing these type of plastic door panels you ask? EPOXY! If I may say, I have personally developed a love for this stuff! This stuff is truly amazing any way you wanna use it. It's as simple as, patty cake, patty cake, mix up A and B.
The first order of business, is strengthening the stress points of the door panels, mainly the door handle. Whoever thought it was a good idea to use plastic door handles on doors that weigh a ton? I decided to use corner braces as they were galvanized, very tough, cheap, easy to come by at your local hardware store and rust resistant.
The tricky part is shaping them accordingly to the part that need bracing. Nothing muscle and ingenuity can't handle. A little bit of adjusting the holes as well is required so the bracing can acquire the screws for the leather pad of the handle.
Here is where they lay, and where they should fit perfectly where the door handle screws on to the door. With the corner braces in place and fitted, these bad boys will take the stress of pulling and pushing the 1 ton doors instead of the 20 year old plastic panel.
Screw on the door handle pad with the corner braces to keep both steady in place while the next step of strengthening the door panels is in order.
Here's the fun part! Mix yourself a liberal amount of the part A and part B of the epoxy, and pour it in the cracks of the crevices. There is no such thing as too much in a job like this.
Some other parts in the door panels have already completely broken off and is nonexistent. I also opted to rebuild those parts out of the epoxy. Here is where the blue tape shines. After shaping box cut outs to the shape of the missing tabs, I taped it in place of where the tabs are supposed to be, and used the blue tape at the bottom as part of the mold of the epoxy. Because the blue tape is designed with an adhesive that peels off clean, after the epoxy dries and cures, the blue tape comes off with ease and no residue.
Other parts like screw tab holes and other thin plastic crossmember parts with broken pieces but are still there, were also rebuilt by sticking them first with super glue to keep them from coming apart before being covered with epoxy for the ultimate strength.
Four years later, all my door panels are as sturdy as they can be, and totally feels like new and just came out the dealership.
Disclaimer: Use at your own risk. If you don't feel comfortable doing a procedure then don't do it. This information is to be used as a guide and is for illustration purposes only. By no means is my site a definitive source for the procedures listed; it is simply how I or the tutorial contributor did things. The tutorial contributor, and I are not responsible in any way for anything that happens as a result of following these guides.
Safety First: When working on your car put safety first. Use common sense and be careful. If you're doing electrical work disconnect the battery. If you need to jack up the car use jack stands and wheel blocks. Common sense is the key.