Bolt size for controle arms?

[niowa98eb]

So my new lower rear control arms came in today and was wondering what size bolts I need to buy. I got the cheap ones off of ebay which are made by pmt but they don't have the hardware included. The nut is a 20mm and the head of the bolt is an 18 mm if they were standard I could figure out the bolt diameter but have no idea about metric. I was thinking a 7/16 or 1/2 in bolt but wasn't sure.

 

[niowa98eb]

I think I figured it out the head size is 1.8x the shaft size for metric so if I have an 18 mm head I have a 10 mm shaft

 

[Thermo]

mjtommy, if in doubt, pull out a bolt, get over to a store like Fastenal (or any other fastener specific store, Home Depot/Lowes/Ace won't be able to help you) and then tell them that you need 4 new bolts to match this one. They will be able to hook you up. Keep in mind that even metric bolts come in different strengths. I would get the strongest possible (the factory ones are the strongest ones based on the markings on the head). Yes, they are probably going to run about $8 a bolt, but what is the cost of having a bolt break when you hit a pot hole in the road?

 

[niowa98eb]

Thanks Thermo. I'm going to pull one since I just found another chart that says it a 12mm.

 

[02Expedition]

"M14x2 100mm 10.9 bolts from Fastenal for $6ea"....from expeditonforum.com