Interior Door Panel Repair

I pulled my passenger door panel to fix one tab I knew was broken, and replace the water vapor barrier, but there was a lot more damage than I'd expected.  I'll go through it all but it'll take a while to get everything posted.

Here's the spot where the screw goes in, on the hinge side of the door panel -



In the past this would have filled me with dismay - but after watching a few plastic welding videos on YouTube, plastic has become my bitch.



The first step is to fill that crack in.  All it takes is a soldering iron, and black plastic zip ties for filler material.  Just melt those puppies right in with the iron.  It's not hard to figure out.  The fumes are no good for your health, so wear a respirator and have a fan blowing them away.

Already this is pretty strong, but we're not done yet!

Next we add a section of hardware cloth for reinforcement -



Use the soldering iron to melt the cloth into the plastic.  This cloth is heavier than I'd have liked, but I still got it in there.  When the cloth is hot enough, it will magically sink into the plastic.  It likes to come back out of the plastic when you move the iron away.  A good way to work is to have the iron in one hand and a set of needlenose pliers in the other, to hold the cloth in until the plastic solidifies.

I filled the hardware cloth with JB Weld so the screw has something to hold on to -



It would be a good idea to tape up the other side of the screw hole so the JB Weld can't leak out onto the pretty side of your door panel.  I did not realize it would run that much, and had to carefully chip it off with a small screwdriver.  I got it off with no damage but it was scary.  

You can hardly tell, but I've drilled a new screw hole through the JB Weld.  After that I ground the top of the repair flush using a grinding stone on a Dremel.  The glass etching bits are also great for grinding JB Weld, but not too hot on the hardware cloth.

"...plastic has become my bitch."

You can say that again. Thanks for posting the instructions!

Albert

The spot where the rear screw goes in, also busted!



But not for long!



A little JB Weld again and we're done -



Here's the tab I got into the door to fix.  This is at the top of the door panel -



It snapped back into place, and I welded the joint shut then put the reinforcing mesh in.  I like this windowscreen mesh better but I only had a small patch left -



At this point I thought I was done, but then I noticed this middle tab was busted too -







I'm curious to see if the driver's side door is this bad, or if all this damage is someone's handiwork.

Moving on to the door itself, I've pulled the old water vapor barrier.  A credit card works pretty well for cutting through the black caulk.  A plastic razor would be ideal, but I don't have any handy.  

I think it's safe to say no one has a pristine example of an 8th gen Riviera water vapor barrier.  Mine has been crumbling apart for years, and the weight of it pulled it off the caulk at the top.  I tried pulling it back in place, but it tore apart instead.   Enough of that!

I've got a box of Noico sound deadener, but I'm not sure how or where I'm going to install it yet.  It looks like it would ideally be installed on the inside of the outer door skin, or possibly on the inside of the interior door panel, with the foamy sound deadener that's currently there reinstalled over it.  I'd rather not add any more weight to the interiorior door panel though, with the plastic aging and cracking; and it seems like it'd be tough to install on the outer door skin.  

I've seen it installed on the inner door skin, but the instructions are adamant about getting the deadener pressed down good, which makes me think that if it's installed right it will be too difficult to pull back to get access to the inside of the door, or it won't be possible to press it down right a 2nd/3rd/4th time.  Plus, the parts over an open area of the inner door skin won't be working right.  It has to be pressed onto a surface to reduce it's vibrations.  Still, it will probably do as much to dampen sound as the Riv's water vapor barrier, it just won't work as well as it could if installed right.

Maybe I can bond it along the top, then use butyl rubber tape along the bottom and sides for accessibility.

Another problem I've come across is a few rust spots under the door handle.



A little Rustzilla and touch up paint will fix this, but it's a surprise that it happened.  Is there a gasket under the door handle that failed?

albertj wrote:

"...plastic has become my bitch."

You can say that again.  Thanks for posting the instructions!

Albert

I'm aghast at all the horrors I've suffered from broken plastic, when it was this easy to fix all along. I could fix office chairs with broken plastic bases now. It's revolutionary!

Some years ago I looked in the McMaster Carr catalog on line and saw what I thought was yardage of the sound deadener sheet goods. I could not figure out how to mold it so I bought a replacement at the dealer. Little did I know they would burn the rest of them... I installed that replacement just a couple three years ago.

Generically something like this oughta work

https://www.gasketsinc.com/product/neoprene-coated-fiberglass-cloth-250f121c/

iff you figure out how to mold it around the speaker driver etc.

albertj wrote:

Some years ago I looked in the McMaster Carr catalog on line and saw what I thought was yardage of the sound deadener sheet goods.  I could not figure out how to mold it so I bought a replacement at the dealer.  Little did I know they would burn the rest of them...

Burn the ones at that dealer, or all of them?

That material didn't hole up well anyway. I'll give the Noico a shot if I can work through the issues with it. I haven't looked at it much yet.

Jack the R wrote:

albertj wrote:

Some years ago I looked in the McMaster Carr catalog on line and saw what I thought was yardage of the sound deadener sheet goods.  I could not figure out how to mold it so I bought a replacement at the dealer.  Little did I know they would burn the rest of them...

Burn the ones at that dealer, or all of them?

That material didn't hole up well anyway.  I'll give the Noico a shot if I can work through the issues with it.  I haven't looked at it much yet.

The material held up well enough for GM's target life time of 10 years +/- ... we are all way past that now. My car has driven far enough to circumnavigate the globe almost 16 times, and is old enough to vote in any US jurisdiction. I'm not happy to have to change that membrane but I am not pissed either. Don't get me started on front control arm bushings, though. They had to know that their geometry for that suspension was (too) aggressive.

Ten years does not seem like enough to me. Perhaps for a Cavalier, but not a Riviera. How are your replacement vapor barriers holding up?

I've got an idea that I might be able to cut the speaker pocket off an old barrier, cut it in a couple places so it lays flat, and use it as a pattern to cut a new pocket from the Noico.

Jack the R wrote:

Ten years does not seem like enough to me.  Perhaps for a Cavalier, but not a Riviera.  How are your replacement vapor barriers holding up?

I've got an idea that I might be able to cut the speaker pocket off an old barrier, cut it in a couple places so it lays flat, and  use it as a pattern to cut a new pocket from the Noico.  

One replacement was an NOS OE barrier I bought some years ago and shelved. It is fine.

The other is a piece of foam sheet like some people use to pack china and crystal in for a move. It is OK, I think I will ahve to replace it in a couple more years depending on how often I have to take the door panel off.

Now that I've got this cleaned up, it looks a lot like body work, doesn't it?  It's a curious place to get a dent.  Maybe first owner's grandson ollied his skateboard into it.  

I've pulled off the driver door panel, and it was less damaged than the passenger side but still not good -







The tab in the last pic isn't totally broken, like it was on the passenger's side, but it is loose and will have to be fixed.

Am I the only one seeing this damage?  I can only think of two sources for the damage on the driver's side - it's regular wear and tear, or the tint installer manhandled the panels off.  I've watched a few tint install videos and it doesn't look like the interior panels have to come off to install tint, which leaves regular "wear and tear."  That's a little disappointing!  Will these panels last another twenty years, even if repaired?

Whether a dealer tech or a body shop, every time in about the past 10 years I've had someone pull the door cards off my Riv they've busted things. The worst part is, even if you leave the body manual with them they still break parts. The chrome hub covers are just as vulnerable - I end up removing my hub covers myself before tire service. Over time the tabs get brittle and if Joe Tech goes after them they will usually break 2 or more of the tabs, rendering them un-mountable (well, you *can* tack them on with a bead of silicone gasket).

I always remove the center caps myself Trust no one!

More damage found -





The thin plastic under the door pull isn't terribly important, since the pull bolts to the inner door panel, but it's annoying to have the pull flopping around when trying to install or remove the heavy door panel.  Most of the plastic was there in one spot and it wasn't hard to fix -



And I managed to do this spot by melting a zip tie in -



If I had to do this job again I'd at least get one of the $100 repair kits. My little 30 watt iron got the job done but it was slow going.

Making progress with the Noico.  It's much easier to work with than I'd thought.  The instructions talk about wearing two sets of rubber gloves to handle it, but I didn't wear any and I didn't cut myself or get it permanently attached to my body.  It's the same gooey rubber as the stock vapor barrier is held on with.  I'm a little dubious about pulling it up again if/when   I need to service anything inside the door.  If it's stuck on properly it might tear up when trying to remove it.  When the time comes I'll try cutting it off with a plastic razor.  That might work well.











That's as far as I can go on this side until I get my dings popped. I'm very happy with the Noico so far. I think it will be a great replacement for the stock water vapor barrier.

Moving on to the rear interior panels.  I think I can get to both of my exterior quarter panel dings through here.

The FSM is next to useless on this job, so I'll post a few pics and instructions.  

First pull the rear seat bottom, I'm sure everyone knows how to do that by now.  Then remove the seat back.  There's two bolts that hold the center seatbelts on, remove them, then lift up on the seat back and it will unhook.

Next, pop off the rear of the trim panel on the door sill and remove the rearmost screw underneath.  The interior quarter panel has a tab that slots under the door sill.  The FSM won't tell you about this step, but I love you more than GM does.





Here's another thing the FSM doesn't mention - there's a small cover over the hole where the seatbelt goes in.  Pull the seatbelt aside and look for the screw that holds the cover on.  Remove that screw so you don't break the tab on that cover, like I did -





At least it says what kind of plastic it is, so I know what I need to fix this with my amazing plastic welding skills.

Believe it or not, this panel is only held on with two plastic fasteners.  You shouldn't have any trouble popping this loose, even without tools.  





And here we have an extraordinary example of Buick build quality - 25 years ago the factory worker who installed this vapor barrier knew I would need to get into that fender to have a dent popped, so they helpfully left this hole uncovered.  You don't get that kind of dedication to customer service with a Lexus!  



I don't think this is a sign of body work, since I didn't find any broken plastic in the quarter panel, and I don't see any sign of adhesive around the top of the hole.  I think it came from the factory this way.

I broke down and bought a plastic welding kit.  I'm sad to say I did business with two of the world's great villains, Amazon and China, but for $50 this is a heckuva value -





Now that I've used this, I regret doing the earlier jobs with a 30 watt iron and scrap wire mesh.  This is soooo much better.

I purchased it to fix this mess I made with the soldering iron -



This is the rear interior panel.  I cracked the corner off by using that part of the door sill to climb into/out of the car.  Unfortunately the plastic there is thin, which made it easy to break and harder to repair.  I wanted it to be stronger than stock so I melted some wire mesh into the bottom, unfortunately I didn't catch that bubble forming on the top.  Pro tip - the interior panel will come out of the car, there's a slot for the seat belt to pass through. You can pull it out and work on it in a convenient location where you might catch your accidents sooner.  Anyway, I couldn't fix this with the soldering iron, but I thought I could push it back down with the triangular tip on the YounJip.  Heat doesn't quite transmit through plastic like that though, the surface cooks long before the heat propagates through the plastic and makes it malleable.  I did manage to smooth it out quite a bit, and after sanding got it to this point -



I'll take it.  I'm afraid if I sand it down further, the mesh will come through the top.  After painting this should be unnoticeable.  Unfortunately paint does not stick well to these interior panels and is easily rubbed off.  I wish I had a good solution for that.

In the first pic you can see a bunch of different types of plastic rods (a separate item).  The door sill was marked as ABS, so I picked one of those and reinforced the bottom of the interior panel -



This is a lot stronger than stock now!  Maybe strong enough that it won't break again.

Incidentally, the bottom of the door sill was marked as a Cadillac product -



How about that?

two things.

Ummm.... Cadillac Products isn't GM, it's a custom plastic fabrication company in Troy, Michigan. They have been around a long time (~1942 IIRC). IIRC they are private; they make a variety of things from milk containers and multilayer packaging films to plastic pallets for shipping 55 Gal drums etc. See https://www.cadprod.com/. My info is the interior of the Riv was subbed to Lear (see https://www.lear.com/) who in turn subbed the plastic panels, some of which would be upholstered (A pillars, C sail panels, etc.) to Cadillac, who are quite good at getting stuff pretty much exactly to spec at a cost effective $ if the quantities are right.

Fascinating. I'm surprised they got to use the Cadillac trademark. Sometimes you can't get away with things like that even when making products in an unrelated field, but they're not quite unrelated if they're making car parts.

It's still cool that it says "Cadillac."

Jack the R wrote:

Fascinating.  I'm surprised they got to use the Cadillac trademark.  Sometimes you can't get away with things like that even when making products in an unrelated field, but they're not quite unrelated if they're making car parts.  

It's still cool that it says "Cadillac."

First - they're not using the Cadillac trademark. There's no real way to confuse plastic film or barrel pallets with a car, to start with, and they are not using the Cadillac wordmark or logo(s).

Secondly, Cadillac is a historic name in Michigan. "Antoine Laumet de La Mothe, sieur de Cadillac," was the French colonist who started the first permanent settlement at Detroit in 1701. GM would not be able to protect the name alone of Cadillac as trademark or copyright, but they certainly could protect the use of the name Cadillac, as well as the styles of logo and wordmarks they develop from time to time, in conjunction with branding of motor(ized) land vehicles.

Finally, there is an interesting thing about family-owned business of this sort. They tend to talk things out and settle or avoid controversies that would disrupt the business, and large businesses tend not to bother them. For instance, put "Apple House Painting" or "Cadillac Janitorial" into a web search engine, and see what hits you get... Cadillac Plastics has been at this a very very long time. See https://www.cadprodauto.com/about-us/#history. I don't directly know but it would not surprise me to find that there is a family-related reason for the name Cadillac Products and a long-running understanding as concerns GM.

albertj wrote:

First - they're not using the Cadillac trademark.  There's no real way to confuse plastic film or barrel pallets with a car, to start with, and they are not using the Cadillac wordmark or logo(s).  

 

I'm not a lawyer and this is not legal advice, but I wouldn't suggest putting that theory into practice. Technically, that should be correct, but in practice let's say you invest a million dollars into creating the "Ferrari Jelly Bean" brand. How many seconds do you think it will be before a company that monitors the Ferrari automotive brand finds your "Ferrari Jelly Bean" company and sends you a cease and desist letter? Not many, and if you're smart you'll fold instantly, write off your million dollar branding effort, and launch "Generic Joe's Jelly Beans." Only a fool is going to risk paying damages and legal fees to a big corporation.

I don't like it, it shouldn't be that way, but that's how it is in current year.