Spare parts and metric measures ?

[Klaus Friedrich #33362]

Gentlemen,

am I wrong or is there a changing in the American measure system?

Bought some restauration parts in the last months in the States which now need metric screws and tools.
For example:
Anti rattle cushions for the side windows of my 69. Former bolts were 1/4" (6,35 mm thread dia.) - now M6 (6 mm thread dia.).
Seat back release button. The grub srew is now M3 (metric).

That means I'll need a second tool set to go on tours across Europe to fix little problems.

Is this a common "problem" or did I just bought the parts in the wrong places?

Klaus Friedrich
#33362
Germany

[Joe L.]

Re: Spare parts and metric measures ?

Klaus-----

A very few parts for pre-76 Corvettes have been converted to metric. Mostly, this occurs because a later part, which is metric size, replaces an earlier part which is US size. You found one of the rare ones. The anti-rattle cushions for the 69-82 side windows are, indeed, one of these parts which converted to metric. The cushion used for 1969-77 Corvettes, GM #3954529, which was standard size, was eventually replaced by GM #14049227 which is metric. GM #14049227 was later replaced by GM #10054691 which I believe is also metric. The latter is likely the part sold by all Corvette parts vendors.

I was unaware of the change in the knob set screw. The 68-69 seat release knobs were discontinued years ago without supercession. I'm sure that GM never changed these to metric set screws. However, it's likely that the "far east" reproduction source for the reproduced knobs either missed this detail when they copied the part or the just went ahead and used metric size fastners which are their standard.

I don't think that this sort of conversion to metric is all that common, but it may become more common as more parts are reproduced in countries which use the metric system as their standard.

I really don't think that there are enough of these out there to warrant the need to carry both US and metric size tool kits in pre-76 Corvettes. For example, these 2 items which are among the very few with metric size fastners, are not going to need immediate attention while you're on the road.

[Patrick H.]

Re: Spare parts and metric measures ?

All I ever do with those window anti-rattle cushions is re-tap them to the correct SAE thread. That solves the problem, and I use my original bolts to hold them in place. I suspect you could do the same with the other screw, or just purchase an SAE thread screw of the correct size.

Patrick

[Joe L.]

Re: Spare parts and metric measures ?

Patrick-----

Yes, if one so-desires, the side window cushions can be easily converted to US thread size.

[Kurt B.]

Question for Joe Lucia

Joe,
Were these window clips used in 68?
Should I have them on my coupe, built May 10, 1968 and exactly where do they get mounted?
Thanks,
Kurt

[Joe L.]

Re: Question for Joe Lucia

Kurt-----

No, the cushions were not used in 1968. That may be ONE of the reasons that 1968's usually exhibit a few more rattles than later C3s. I suspect that the cushions were one of the early efforts in C3 evolution to eliminate some of these troublesome qualities.

[Klaus Friedrich #33362]

Gentlemen - thank you for your thoughts *NM*