Despite having both the FSM and several Parts and Illustration catalogs, I am continually failing to locate specific fasteners for various interior parts in my son's 1990 without resorting to trial and error. He removed the passenger side hush panel in order to access the "auxilliary fuse block" (my discovery of the existence of which when troubleshooting the power door lock circuit led to a few uttered choice words regarding GM engineering). He misplaced the fasteners (one of which was already missing anyway) and so I'd like to see if I can find out what the original size and type were.

This is the hush panel I'm talking about:



Looks like there are three screws through the bottom of it into the I/P bracket assembly and then one tab that's sandwiched in with a fuse block retaining screw. It seems like most of the interior screws in this thing are metric hex washer head self-tapping sheet metal screws, but I cannot for the life of me seem to find the specific diameter and length needed for each of these in any reference documentation I've got. And the "interior screw set" we purchased from Zip Corvette has thus far proven to have exactly none of the fasteners we have needed. Thanks in advance for any light anyone could shed. If anyone happens to have this out already, just letting me know what size the hex head is (maybe 8mm?) and measuring the length would be a huge help. And if this information actually IS contained somewhere in the parts catalog and someone knows the arcane magic of locating it (WVZR-1?), please let me know!

 

OK, no answers in a few days suggests to me folks just don't have the info. If anyone happens to be working on their interior in the next few days, could someone just let me know what size hex head is on the fasteners in those bottom holes? That should at least get me the right diameter and I can experiment with what lengths work best.

 

Just for future reference, if it's not a "Phillips" drive fastener, on GM vehicles '80s and newer, 99% of the time it's going to be a 7mm head for smaller diameter (interior) and 10mm head for larger diameter (body bolts). For your hush panel, it may have come with a little a smaller diameter washer fastener for some of the holes, but I find it's best to use these, as it spreads out the clamping force, reducing the chance of cracking (see picture). My local preferred parts store carries Disco brand fasteners, I also recommend Auveco brand fasteners. If you do have any cracking, I recommend this particular JB Weld epoxy, works great on many plastics, especially ABS like your hush panel is made of. I also highly recommend the static mixer tubes, you can get the epoxy into a very precise location and the mixture is perfect. Only downside is they are a one time use, but cheap enough! If you have any cracking around a hole, use some of this on the backside (top) that you won't see when mounted.


I swirl it around the screw hole to whatever diameter it needs to be to cover the cracking and a little beyond. Keep the it the thickness of popsicle stick or so and it will have no effect on mounting! Hopefully this helps, good luck👍

 

Right ON: 7 & 10 mm ...........

 

M4.2x1.41 in GM is 7mm HEX, M6.3x1.81 in GM is 10mm HEX

Fastenal Stores generally have Au-Ve-Co Products (Auveco) screws and automotive hardware in stock. You can generally avoid the 50 pack quantities I believe.