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upper control arm bolt replacement??

9

95XJ_Cbiscuit70

NAXJA Forum User
Location
South Jersey
In process of installing RC 4.5 long arm kit and upper control arm bolts are corroded tight. PB and heat not working. I am thinking of cutting and replacing. Are grade 8 an equal swap for factory bolts? Not sure where to find material properties for factory fasteners to compare.
TIA
 
Are we talking upper, frame side or lower, axle side? Either way are metric, metric 10.9~SAE grade 8. But yes, you can replace them.
5-90's site kelleywip.com has fastener sizes, if thats what you are looking for.
 
Not exactly "any decent hardware store".
they are M10x70 case hardened fasteners and I can't even get them at local industrial fastener distributors. Case hardened have an additional processing step that increases their material properties so a standard off the shelf 10.9 is not equivalent to a case hardened. At least that is what the guy told me at the last place I tried. Said he would sell me standard 10.9 but it was at my risk.
Has anyone tracked down an internet source for these bolts?
(two bolts, four flat washers, and two hex nuts for Upper control arm mounting bolts at front axle)
 
IIRC they are actually a 12.9 but I could be wrong. The dimensions given are correct.

I have heard of various people boring the bushing sleeves out to an SAE size slightly above 10mm - I want to say 7/16" but I am honestly not sure.
 
I bored out the bushing sleeve on mine to accept a 1/2 grade 8 bolt. i had to do this because of my currie arms. it got rid of the dimples and barely scratched the walls..
 
Must be the size I'm thinking of.

You may have trouble keeping the drill from snagging on the dimples - a drill press and proper clamping of the work can help with this.
 
95XJ_Cbiscuit70 said:
.... Case hardened have an additional processing step that increases their material properties so a standard off the shelf 10.9 is not equivalent to a case hardened. At least that is what the guy told me at the last place I tried.
Click to expand...

That guy is full of BS.

10.9 or Grade 8, hardened is hardened, end of story.
 
Last edited:
Grade 8 1/2" is the way to go. If you break a Grade 8 On a control arm your doing sometging wrong with the steering whell, gas/break pedal. A standard grade 8 works perfect for control armsand everything else. Grade 5 bolts are more for winch mounting because they have a Better tearing factor, but hell I use grade 8 for all my replacement bolts and never had one break. Really funny thing is that i break factory bolts 100% over breaking the grade 8's
 
9/16" is actually closer to the factory LCA bolt size than 1/2" but otherwise I agree. Certainly 1/2" for uppers.

Factory LCA bolts are M14, which is 0.551", 11 thousandths of an inch smaller than a 9/16 bolt.
 
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