Broken Screws & Grabits

I have discovered a number of places on our '07 2720sl where the heads of sheet metal screws have fallen off. This may have happened because the torque setting on a factory worker's drill was set too high and the heads were weakened where they attach to the threaded portion of the screw & eventually sheared off. I don't think it is due to excessive road vibration --- because of the routes that I choose and the speeds that I travel.

The factory's suggestions (grab the broken end with a needle nose pliers or drill out the broken screw) are not satisfactory solutions. First -- I can't actually grab the broken ends because they are somewhat below the aluminum skin and drilling out the broken screws is likely to produce a large, nasty, irregular hole that will require patching or a much larger screw.

So, tonight I saw an ad on TV for a Grabit, screw & bolt removal set. I was wondering if anyone has ever used Grabits to remove #8 or #10 screws ? Does anyone have any other suggestions on how to remove these broken screws without unnecessarily damaging the aluminum skin?

Thanks, Eric

[commodor47]

Eric,

Just curious, are these the screws that hold the windows in place? I have used a similar tool to remove small, headless wood screws. That does involve drilling a small pilot hole in the remaining portion of the screw large enough to accommodate the removal tool. But the broken screw was too small. I ended up drilling a larger hole in what was left of the screw. By gradually increasing the drill diameter I was able to use a small nail set to collapse the remaining thread into the drilled out space and pry out the broken screw. I am pretty sure the screws you are referring to are aluminum. Although it will be tedious work, you should be able to drill out the broken portion. It might help to remove an existing (unbroken) screw to use as a drill size guide.

[Keith Wire]

Eric,

We have an '07 2720SL too and I haven't noticed any broken screws. Where are they?

We own a hardware store and have sold some of the "grabit" tools that I think you are talking about... Is this what you are referring to?

http://doitbest.com/Drill+Bits-Alden...sku-358215.dib

If so, I don't think they will help you if the head is broken off. I believe they are made to help remove a phillips headed screw where the head has stripped out. They have a "burnisher" on one side (that does drill down into the screw head just a bit) and a screw extractor on the other side to back the screw out.

If the head is actually broken off as you said you can try drilling down the center of the screw and try using a screw extractor, or try what the Commodore has suggested. But, if that doesn't work I think the only thing to do is drill a hole beside the one with the broken head, and install a new screw. You could then caulk over the old hole.

Keith

You may not notice that your screws have been damaged by being over-torqued at the factory until the day when you do a routine check of screw and bolt tension -- to be sure that nothing has vibrated loose. I had read several threads that recommended a periodic check of screws and bolts and when I inserted my little square screwdriver I found that the screws turned effortlessly then the heads fell off. I would never attempt to tighten screws in the trim and corner edges with a cordless drill. I would always want to control torque with my own hand. Quite frankly, after running into two out of six problem screws -- I stopped checking screw tension cause I didn't want to discover any more poorly set screws. Yes, this is the head-in-the-sand maintenance method.
I was kind of upset and Ed at the factory was kind enough to send me a supply of screws of varying lengths and diameters so that I could do my own repairs. But, so far, I've been unable to remove the small broken screws so I've dabbed white silicone over the holes until I discover a better fix. The drill tends to wander all over the place when I attempt to "drill-out" the small broken screws and the aluminum skin tears easily.

I think that the Grabit extractors are different than what is depicted by Keith. There are four different sizes and each has a conical cutter that fits into a drill and creates a small cone (is this what Keith means by "burnishing" ?? ), not a hole, in the end of each broken screw or bolt. The opposite end of the tool has a conical gripper / extractor that fits into the cone that you create and somehow grips when counterclockwise pressure is provided.
It's different than the ease-outs we used to use to remove broken head or valve cover bolts. Maybe it will be easier to create a conical indentation than burrowing a tiny hole in a #8 or #10 screw shaft ? I don't have a clue if its going to work but I went ahead and bought the set of four for $20 plus $6 shipping. I'll be sure to share my Grabit experience with the forum members.

It's just not my style to use silicone to hide problems and I won't get aggressive with drilling new holes until I've done more research. I sure appreciate the suggestions. You guys are great.
Eric

[Bill]

Eric -

Please let us know how the Grabits work for you. Unfortunately, I think Keith will turn out to be right. In order to make the conical hole, the Grabit expects that a hole of some kind already exists, though it may be a very messed up hole (stripped Phillips head, for example). The burnishing end of the Grabit simply improves the shape of that hole, so that the extractor end can grip the sides of the hole. Take a look at this link to get a better idea of how they work.
http://www.4grabit.com/Default.asp?bhcp=1

On the other hand, drilling a hole in the screw shank shouldn't be impossible. It would be easy to do if you could clamp the whole TM on a drill press table, but obviously you can't do that. However, a trick that I have used with moderate success is this. Get a piece of acrylic or plexiglass, maybe 3" square. Put a small bit in your drill and drill a hole in the middle of the plexiglass. Now unchuck the bit, and re-seat it DEEPLY into the chuck. The amount protruding from the chuck should be equal to the thickness of the plexi plus about 1/8". Now hold the plexi FIRMLY against the side of the TM, so that the predrilled hole is over the center of the screw shank. Put the drill bit through the hole, and slowly drill into the shank. Not much forward pressure on the drill. The plexi keeps the drill bit from wandering, and the fact that only a small amount of the bit is outside the chuck keeps the bit from bending. This jig would be better if made of metal rather than plexi, but you need to be able to see through it, to put the tip of the drill bit in the right spot.

This is a practiced art, and the fact that the plexi will be resting on an uneven base - the piece of trim - will complicate it. It may, in fact, turn out to be a two-person job. But with some care, and maybe shimming up the plexi a little bit so its surface is better supported, it may work. Once you have an initial hole in the screw shank, it is a lot easier to make the hole deeper and wider, and at some point the Grabit should be able to (ahem) grab it.

Bill

Thanks Bill et. al.,
Maybe I can shim (with garden hose washers or ?) under the plexiglass to create a level, work-surface and then use my gorrilla tape to secure a few edges of the plexiglass and hold the alignment.
I think Bill's technique has real possibilities. I'll still give the Grabits a try. The TV ad showed one of them being used on a screw shaft --- without even a stripped screw head. This is what gave me hope. But I'll suit and gown up --- like I'm going to do micro surgery and use the BSRM (Bill's Screw Removal Technique). Thank you, Guys.