I also got a locking nut.

 

Grade 8 locking nut

 

Strange...
In my service manual it states it is a M10 x 1.25 bolt, not a M12 like on the websites of automotiveparts and San Leandro Honda.
Looking at the picture I would say M10.
But now I'm not sure.


Me an expert....

 

Ok.
I just came back from my weekly engine oil level / tire pressure / suspension bolt check
I can confirm 100% the bolt holding the lower strut on the shock absorber assembly is...

12 mm.

My bad
(damn service manual )

 

I think you'll be fine with Grade 8...that's about as strong as they come on US built cars and are used on suspension.

 

The grade 8 bolt I got from Napa ended up being too big. They didn't have metric bolts of that size so I took one the guy said was close to what I needed. I didn't realize metric and US didn't have exactly matching bolts. doh!

I think I will just order the OEM bolt and a nut for it.

 

^ Make sure to get a stock bolt, so it's the right diameter for the control arm. I tried to replace mine with some other bolts and couldn't find one that didn't rattle.

 

Typically the OEM suspension bolts are knurled to make them fit the bushing holes better. Home Depot sells metric bolts and nuts. Metric grades and SAE grades are different.

Honda says replace them every time you take them off but, I never to.

 

I tried Home Depot and no luck. Lowes is where I got the one I am using now, but it is a class 8.8 (grade 5).

 

Grade 5's fine. It's holding up at best 700 lbs of weight. Grade 5 is more maliable than grade 8 which means it'll bend where grade 8 would snap. You used a self locking nut?