95 Lumina rear strut bolts

I'm replacing the rear struts on a 1995 Lumina sedan, the large bolts that attach the lower end of the strut to the knuckle have a round head/2 flats & a spline on the shank under the head. I was able to remove them but the bolt threads & the nuts are toast. The bolts were spinning in the knuckle so I'm not sure what the spline is for? Are these needed to align the rear properly? Can they be replaced with grade 8 bolts from the hardware store? Can't find any at the local dealers but got prices around $8/bolt!! Cost isn't really the issue as much as time, this is my daily driver and I need to get it back on the road. Anyone else run into this? Suggestions appreciated, Thanks!

You might try a local junk yard for useable bolts. Generally a GM dealer will pick up a set at the warehouse. Call early in the day and they should be in by lunch time. Generally strut bolts for alignment have a cam on one side and a flat spot for a cam on the side for the nut a cam on both sides.
This year Lumina will have metric bolts probably grade 10.9 which almost surely will have to be ordered. Look in your manual it will tell you if the bolt is for alignment. Usually only one of the two will be for alignment. Are you talking front as most GM vehicles use springs and shocks not struts on the rear.

You might try a local junk yard for useable bolts. Generally a GM dealer will pick up a set at the warehouse. Call early in the day and they should be in by lunch time. Generally strut bolts for alignment have a cam on one side and a flat spot for a cam on the side for the nut a cam on both sides.
This year Lumina will have metric bolts probably grade 10.9 which almost surely will have to be ordered. Look in your manual it will tell you if the bolt is for alignment. Usually only one of the two will be for alignment. Are you talking front as most GM vehicles use springs and shocks not struts on the rear.

Yeah, I'm going to dig through the manual to see if I can figure it out. :runaround: It is the rear and most definately a strut assembly. Thanks.

The rear bolts aren't special for alignment, rear camber is adjusted by eccentric bolt holes allowing you to slide the strut back and forth. I think the reason those bolts are 3/4 round and 1/4 flat is a total mystery. You're going to want the correct bolts, because they're purposely slotted for roughness on the shank, and the correct hardness is important too.