[izonpro]

I want to lower my car. The rear spring has 6 1/2"or 7" bolts now. Want to go to a 10" bolt. My stock bolt is a 9/16" grade 8 bolt. Can I go with a 1/2" grade 8, 10" bolt instead of the 9/16". How important is that 1/16". Also do I need fine thread or is course OK. Thanks for the feedback.

 

[redvetracr]

I would stick with 9/16...on my racer I upgraded to 5/8
...redvetracr

 

[yellow73sb]

I also have 5/8

 

[izonpro]

will 5/8 fit through the existing washers, bushings, spring, and trailing arm?

 

[lsejlowe]

will 5/8 fit through the existing washers, bushings, spring, and trailing arm?

not quite, but it wouldn't take much to make 'em fit. However, your best bet is to just stick with 9/16. No reason to risk cutting it to 1/2 and not necessary for typical driving to go up to 5/8.

 

[gtr1999]

You also need the fine thread for adjustment tuning. If going with a 10" bolt be sure you are clear of the tire sidewall.
I had to use 8" bolts with all the aftermarket steel springs I bought, even the one a vendor told me would work on with the 6.25 bolts- wrong.