Screws pulling out -- repair

I am finding screws pulling out of the aluminum shell on my '04 3326 King. It is due to the high stress placed on the screws and the fact that they are anchored in a thin layer of relatively soft aluminum. I am looking for a general purpose repair for this. I also see movement of the attachments in various areas.
* The spring loaded latches and the clamp down latches at the corners move.
* The pull-out handle for the bed moves.
* Recently the 2 screws holding the door jam spring clip pulled out of the upper shell. This is on the latch surface of the door.

I made a repair for the last one which I will describe. The repair was performed in a campground and was basically done using JB Weld epoxy found at an auto parts store for about $4. The pulled screws go thru the clip, the aluminum inner wall, and the square frame tubing. The epoxy needs 15 hours to cure completely but is run-free in about 1 hour. The tools I used included
* A plastic knife and Pringles box top for mixing and
* two "F" wood clamps, duct tape, and an aluminum tire iron to hold the joint together during the cure.

* Access to the area was gained by removing screws along the upper door jam and prying the jam trim out about 1/4 inch. This trim is strongly attached to the outer skin and that bond was not broken by this repair.
* A paper towel plug was pressed into the square tube opening to capture the epoxy and prevent it from running along into the tube.
* Duct tape was applied at the upper shell corner below the repair area to form a cup to keep the fresh epoxy inside the tube.
* A batch of JB Weld was mixed including pieces of paper towel about 1/2 inch square to act as a thickener preventing epoxy from running back out of the repair area.
* The removed screws (3 or 4) that went into the epoxy were smeared with grease to permit possible removal of the screws at a future date. The screws were inserted back into the holes from which they were removed.
* The door jam closed with the pin snapped into the clip.
* The joint was clamped together. The tire-iron was used to extend clamping pressure to the clip with the door closed and locked.

The repair withstood the trip home and appears to be as good as new (or better). JB Weld is an extremely tough form of epoxy used for metal repair and the remaining half of the material is in my repair box if/when it is needed in the future.

Bob

I've never used JB Weld but I know a lot of people swear by it (not at it ;-D ).

That sounds like a good method of holding the loosened screws in place. May I suggest that you use fiberglass fibers to thicken your JB weld resin the next time. They are much stronger than paper fibers. You can find small repair packets of fiberglass cloth at any hardware store - just cut short lengths of fiber from the ends of the cloth. Also, store your JB Weld in a refrigerator. It will have a longer storage life if kept there rather than in your toolbox. You just need to remind yourself to get it out of the refrigerator before you leave on a trip.

I use hollow wall anchors to replace the screws that have pulled out of the thin aluminum walls of the TM.
I buy the shortest length available which, I believe, is 1". You remove the item that is attached to the wall, insert the anchor in the hole and tighten the screw which then expands the anchor behind the wall. You then remove the screw, insert the screw through the item to be attached and screw it down into the anchor.
These anchors are widely available and are made of a soft steel. Do not use plastic plugs as they will not hold.
I have had so many screws pull out that I purchased a large box of these hollow wall anchors. All my drawer supports came loose and the TV cabinet and tub faucet mount pulled away from the wall.
IMHO it is high time the factory found a better attachment method. A screw into thin sheet aluminum is only good enough to hold up something very light weight such as the dome lights.

I don't want to start a new thread, so I will revive this one.

When checking for loose screws don't forget to look inside the outside cover for the water heater. Of the 4 screws holding the cover framework to the TM, one was tight and the other three were very loose. These are not visible in a walk around inspection. You need to remove the cover to see them.

Good job Bob, I have used JB Weld also on various things and has worked well. I have found when working with alumnum fastners it can be very difficullt if you need a strong solid attachment to what ever. TM might look at an alumnum alloy for these points of attachments. TM has in the past listened to its customers and has improved its product, hopefully they will follow up with this issue.

MidWest Dave
Where the Mississippi River runs west

Here is another suggestion for reattaching the corner latches. I am going to use aluminum pop rivet nuts from McMaster Carr; 93482A643. They go thru a .25 dia hole and accept a 10-24 thread screws. If bending of the latch still ocurrs, a 1.5 inch long screw could reach the inside wall of the top section.
Jan Rooks, Troy, MI.

I read this thread with interest because I'm anticipating this problem myself. What I would be worried about with using expoxy for repairs is what to do if you ever have to remove the screws to make another repair?

I'm wondering if the factory just applied some type of thread lock compound to the screws if they wouldn't stay in better. The anchor idea provides a way to loosen the screw. What happens if you pull it all the way out though? Does the anchor kind of stay in place in the styrofoam middle?

I plan on painting all the outside screw heads this spring with clear nail polish. This really kept the rust at bay on my old Class C. not sure it did much to hold the screw in- although I suppose it couldn't hurt.

Phil

[arniland]

In one of my previous lifetimes I was involved in preparing cars for sports car racing and then with homebuilt aircraft. In these I became familiar with what I always referred to as "blind fasteners". I seem to remember that the folks who made pop rivets had an inexpensive consumer line of these products. You installed them with a standard pop-rivet tool. The inserts, however, have machine threads in the center.

As the TM is constructed with aluminum skins, these would leave threads which should be stronger that the sheet metal screws originally used.

I have a full kit which I bought at an estate sale (a retired aircraft mechanic) which has the tool and inserts for the sizes; 6-32, 8-32, 10-32, 1/4-20 and 5/16-18. My frustration is that I have not yet found a source for replacement inserts. The brand I have is Tric-Nut from a firm named Aviband in Burbank, CA. I have no idea of how old it is or if the company is still in existence. However, someone must be still manufacturing blind fasteners. I also have a tool and a few fasteners which were made by BF Goodrich called Rivnuts, but I do not believe that they are still in production.

Like Phil, I have anticipated that eventually I would experience failures with sheet metal screws and this is how I intend to repair them. I have successfully used these on a friend's Hi-Lo.

Has anyone else tried this approach? I believe that these are a good, well engineered solution which should outlast the TM if properly installed.

Arn

[Bill]

Arn -

Both rivnuts and tric-nuts are apparently available from many suppliers, as indicated by the hits in a Google search. You're right, Aviband seems to be gone, but there are others.

Bill

Arnold- Bill's right, these things exist all over the place. I fund a bunch of folks on Ebay that sell various versions of these thingys. Very promising. I've never pop riveted anything so I'm assuming with these you just make sure you have a proper sized hole and use a pop rivet gun to squish the back against the metal. Then use a Stainless screw with some locktight or something to finish the repair? How do you figure out which one of these things to buy? There are a ton of them. I would imagine they'd have to be pretty short to hold tight to the aluminum panels. Any recommendations on what size to buy for general "trim" type repairs? I'm guessing if you really need some super strength, you wouldn't be using these?? Or am I not thinking right about how effective these are?

Phil