I use Mobile-1 10w-30 synthetic oil from Walmart in my equipment. It's $60 for a 12qt cardboard container, 10-40w is the same price.

Ha.. Good onya.. Perseverance always wins. Yeah you'd have spotted a bend or ripples in the frame if it was bent I'm sure. And don't feel bad.. mechanics stuff things up all the time.. and a lot of them are too perverse to even backtrack half way through assembly when they realise something doesn't seem right.. They'd just have told you the knuckle was bent when they took it apart for the second time after you complained about it pulling left. Thieving mongrels.. Admit doing something wrong and you have to pay, sell the customer some more work and it's more parts profit and hours booked out successfully.. It's why I was self employed since I was 21. And those cast bits, called Knuckles in the book I see, they do bend.. surprisingly. If anyone else is having the trouble, don't discount the knuckle just because it looks so solid..