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MG MGA - Can't tighten bolts up under the dash
|I've located the really annoying rattle coming from the left side of my dash on my 1960 A at idle. There's a bolt up under there that's supposed to tighten the dash up against the top panel, but it just spins. so obviously a captive nut has broken loose? It's boxed within some bracing and there's no way of getting a wrench on it.|
Does anyone know of a fix? I've wedged a piece of cardboard between the metal tongue of the dash and the top panel to stop the rattling, but that's hard ly a fix!
|Just reading mga guru dasboard re are re and are those 3 bolts up top actually metal screws? Maybe the PO used ones too small and they're not grabbing. I was reluctant to thread it out to see what the bolt looked like.|
|These are PPZ0308 - Pan head Pointed Zinc #10-32 x 1/2. I'm sure they screw into square floating cage nuts. Mine have been apart periodically over the life of the car, never rusted in place, thank goodness.|
The cage nuts are inside the channel and inaccessible. You likely cannot replace them without disassembly of the body weldment. But where there's a will there's a way. Try this:
If you cannot unscrew the fastener, then grind the head off, and remove the dash assembly. Then continue grinding on the channel until you have a hole large enough so the square nut will fall out. Weld a new #10-32-UNF nut (hex nut will do) to a large flat washer. Place the nut and washer assembly with nut inside the hole and the washer flat on the underside of the channel. It would be nice to tack weld it in place. If you don't want to do welding you might secure it in place with a few small flat head screws around the perimeter. When you reinstall the dash you can bend the tab down slightly to compensate for thickness of the washer.
|The three dashboard fixing screws are 3/4" 10-32 pan head machine screws. I had a similar problem on my boot lid with spinning caged nuts but it was relatively easy to fix because there was some access to the cages.|
In the dashboard case there is no access to the nut and its cage whatsoever which is spot welded to a plate which in turn is welded across the top hat brace section. To repair it properly would be a nightmare and would involve grinding away a section of the plate complete with cage and welding in a new piece including a new cage and nut.
However, assuming you can't get the original screw out, take a look at the dash bracket and you'll see there is about 1/2" of land surrounding the hole. Also there is plenty of room on the body plate so you could drill a hole through both the bracket and plate and put in something like a no 6 self tap screw. Take care you don't drill through the scuttle panel!
You might have to open out a clearance hole in the bracket. You could even put in a couple of self tap screws for a stronger job. I'm not sure how much access you would have for drilling up there with a LHD dashboard................ Mike
|You can try running a 10/32 hand tap through the cage nut very slowly to restore the threads. Be sure to also run the screw through a die if you are reusing old hardware. |
If the threads are clean enough, you can usually then get the bolt to thread in and tighten without spinning the cage nut.
I did this and it worked fine. Try this before drilling new holes or hacking away at the rails.
IIRC, there is a fender washer and lockwasher that go on the machine screw here.
JIM in NH
|Thanks guys, actually the problem is that the nut has broken loose and I can't tighten up the screw which is still threaded into the nut. So if I remove the screw and get the nut to drop out maybe I can perform Barney's fix with a little JB weld?|
|Maybe a few drops of thread lock fluid might do the trick?|
|Graham M V|
This thread was discussed on 04/05/2012
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