575M Air Conditioning Panel Mounting Tabs Breaking

Something for 575M owners to watch in the future.

While visiting Santa Fe for an FCA luncheon, I used my window switch to lower the window and talk to someone. When I did, the entire air conditioning and switch panel started to pull loose at the top. It easily pushed back in and seated. No sweat, I thought, a five minute job to tighten and my tech, Signor Buona Wrencha (Aaron) has all the plastic tools for pulling the two outside, top switches on each side to reach the mounting screws and he could tighten them, no sweat. When Aaron tried to tighten it, however, both of the plastic mounting tabs more or less disintegrated.

New fascias are not available as a separate item in the parts catalog and even Rod Drew at FAI said they were not available separately. Ricambi's price is $2500 for the entire panel and all the switches on the front and back, way too rich for me. I noticed Robbie of Sticky No More said he had some 550 A/C panels for sale, so I gave him a call. He said he had already seen 575M panels with broken tabs and that he did not have a panel for sale, but did have one he would loan me. Good old Robbie to the rescue. We are lucky to have him in our community.

So Aaron and I will use Robbie's panel just for measurements and photos, and then document the repair so if it happens to you, you or your tech will know how to fix it. We intend to make metal tabs rather than the plastic ones, which apparently could not take the heat of all those nearby switches.

The two images below show the panel with the outside switches removed to access the mounting screws. The second image shows the mounting tabs on the back after the panel has been pulled.

The real reason for writing this, though, is to recommend you open your windows slightly differently. If you just reach up and pull down on the switch, you are applying pressure to those tabs, and they may eventually break, like mine did. If instead, you use one finger to push on the top edge of the panel while pulling down on the switch with another finger, the mounting tabs' survival time will be greatly extended. That is what I am doing now, and it works fine, and I do not even have tabs.

Taz
Terry Phillips
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Alex- Affirmative. Broken stuff is unacceptable. Are you going for the $2500 fix or the Taz fix?

Taz
Terry Phillips

 

Received Robbie's A/C fascia today and it is a perfect example of what is happening. As you can see, one tab has broken and the other is cracked and not long for this world. And this is his good one. The problem is twofold, first the heat is embrittling the plastic, and second, the switches that fit into the slots rub against the mounting tabs as they are removed and replaced. Mine is in much worse shape than this one.

Luckily, if you look at the panel, the mounting tabs are flush with the switch slots on the inside, leaving plenty of room on the outside for reinforcement or a new metal tab with a 90 deg bend in the bottom acting as a foot and surface for adhesive, either epoxy or cyanoacrylate, whichever is less likely to eat the plastic. Epoxy, most likely.

To make matters a little more fun, the mounting face on the tabs is at an angle to the panel. Looking closely, though, the tabs are isosceles triangles with the top cut off parallel to the base and the bottom two legs cut at angles that should be fairly easy to match.

I am thinking brass shim stock for replacement tabs, but am open to suggestions. Easy ro bend and relatively stiff. Hate to use plastic again and have it embrittle like the original.

Will show it to Aaron next week and see what he says.

Incidentally, the clear plastic panel on the back is the diffraction grid for lighting the panel.

Yes, Robbie's panel is from a Euro 575.

Taz
Terry Phillips
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Dave- 5052 might be a good alternative to brass. Some panels have a generous bonding surface, like Robbie's, but my tabs are mere stumps. Robbie's other panel is apparently about as bad as mine.

Do you have a source for the 5052 sheets? Have not tried the Devcon. How much plastic does it dissolve? My idea is to make a pattern that anyone could use to make their own repair overlay. There is not enough material in mine for a rivet. The tabs are pretty thin plastic

Taz
Terry Phillips

 

Dave- Mine does not have any side tabs left. Remember, this is Robbie's good one. I want a one piece thing that has the side tabs, mounting tab, and two feet all in one piece of bent metal. Bend to shape, drill the mounting hole (maybe do that first), and bond to whatever remains of the side tabs, stumps or not.

Robbie's will be the test case.

Taz
Terry Phillips

 

Dave- Thanks. Will follow your advice, as usual. Pretty sure epoxy will work without causing other problems. There are so many different types of plastic now, you are never sure what will bond and what will not.

Taz
Terry phillips

 

Dave- Thanks. Have not used it, but it looks good.

Taz
Terry Phillips

 

Bruce- Thanks. Have not worked with aluminum all that much, so any helpful hints are valuable. I like epoxy, but then I had 10 Corvettes, so I am predisposed towards that material. You are right. Cyanoacrylate is better than 5 minute epoxy.

Taz
Terry Phillips

 

I made a crude drawing of a repair panel for the air conditioning panel and then did a paper fit check. Considering I could not find any of my drafting tools (who knows after 20 years in the same house) and used dots on pieces of stick-ems for lengths and folds for angles, the results were pretty good. I ordered some real measuring tools and will produce drawings for everybody to use that have dimensions and angles accurately portrayed.

Right now, though, if I had some sheet aluminum and a jig saw or metal shears, it would be easy to make repair panels that worked. Once everything is in hand, Aaron and I will repair Robbie's panel first and then mine. May have to make some minor mods to the drawings to make up for bend radius. I also note Ferrari, for come reason, truncated the actual tab and then put the mounting hole too close to the edge, helping it fail. We will leave the tab bigger and see if that works. Will be stonger if it does.

The idea is to make a repair panel that will work regardless of how far gone your tabs are. From merely cracked like Robbie's on one side, to nothing left but stubs like mine, the repair panel should work for all of them.

Any hints from anybody on what thickness 5052 aluminum sheet I should use? There is actually not that much pressure on the mount. It is just that the heat kills the plastic and any stress finishes the tab.

Taz
Terry Phillips
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Dave- Thicker than I would have thought, thanks. About a twelfth of an inch (1/12.5" acutally).

Taz
Terry Phillips

 

Dave- I ordered some .08 and .05, so I should be covered. Only about $10. Cost more to ship it. If it can be cut with metal shears it will be a big advantage. All the bends will provide quite a bit of strength, especially once bonded in place. I like your idea of glue holes for those with a large bonding surface.

Guess I should not have given away my 9" band saw and drill press.

Taz
terry Phillips

 

Dave- Good point. Cost would only be about a buck each. Eventually, there will be a market for ~4000 of the things.

Taz
Terry Phillips

 

J- So you used a full length panel between the two outside brackets for the tabs? There is a lot more surface for bonding on the two separate pieces.

Taz
Terry Phillips