As the shop instructed says "Righty tightly, Lefty loosly." They are a right hand thread.
This might be the time to look at Harbour Freight for their 1/2 inch electric impact tool. I have one and it works pretty well on spring bolts. They are usually on sale for under $30.

Penetrating oil and heat also help.
Good luck


1954 Chevy Half-Ton
In the Stovebolt Gallery
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1958 Chevy 1/2-Ton Stepside
In the Stovebolt Gallery
More pix on Photobucket

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"Time's fun when you're having flies." ~~ OLD FROG