Rear spoiler help

[rockdogz]

The studs on the rear spoiler seem to be 1/4-20 thread, but when I try the nuts on them that are supposed to be for the rear spoiler (2 different packs!) they go on one turn then stop. I tried to run my 1/4-20 die over the threads but it starts killing the threads too!! Any thoughts what the problem could be? Would they really put metric threads on??

[Jim Nilsen]

I think they might be 1/4-28 fine thread , I will have to check mine to be sure.

Jim Nilsen

[Jim Nilsen]

I went out and checked my spoilers. I have an original from a long time ago and a new GM spoiler I bought about 4 yrs ago. The original has 1/4-28 threads and the newer one has 1/4-20 threads. The change was probably made by the change in the supplier of the fasteners themselves. The cost of tooling to make them was probably not a question but rather the convenience of the tooling being in the shop that made them at the time. It shouldn't make any difference in the long run but fine thread fasteners usually won't vibrate loose as easily which is why years ago when they made them you got the quality.

Hope this keeps you all from going crazy since GM didn't supply my new spoiler with new nuts and the old ones would have driven you there trying to get them to fit on the new one and the nuts you have laying around are probably 1/4-20.

Jim Nilsen

[rockdogz]

Hey Jim it turned out that this repro spoiler I got from Classic had metric threads!! At least I figured it out before I stripped them...
Thanks for checking yours out - Frank I'm finally using your (excellent!) bolt kit and you might want to make a note of this for the spoiler hardware!

[PRO TC]

ya you should have know that all the repop stuff is made in china.lol
barry