Quote:
Originally Posted by C5GTO
While my lower control arm is tubular instead of press steel, it still uses a 1/2" bolt for the bottom of the shock. I'd suggest using a grade 8 bolt, but yes the same bolts have worked fine on mine for about 25 years now.
I didn't know if the 8" spring measurement you were asking about was free or compressed length, so I broke out the floor jack and took a bunch of measurements.
- spring compressed length = 7"
- spring free length = 8 3/4"
- shock compressed length = 14 1/2"
- shock free length = 16 1/2"
There's a 2 1/2" extension on the top of my shock so the actual shock length is what I gave above minus 2 1/2". I'm guessing the extension is a CR thing given the tall shock mount on the top. I'm guessing you might also need a shock extension unless the shocks you have match the measurements above. I don't recall when or where I got those extensions but I bet they are not optional on a CR.
The height adjuster on the shock is right about the middle of the threads and there's about 1 1/2" of threads above it. So an 8" spring would work but the adjuster could be getting close to the top of the threads. Again, I have Cararra shocks so the QA1 shocks maybe different.
I hope this info helps you out.
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Using a top stud extension on a shorter shock / coilover would be an alternative to opening up the top hole, though I do have concerns about using a stud extension on a coilover due to the possibility of lateral loading over the increased length of what is essentially a 3/8" bolt vs 5/8" hardened steel shock shaft. That's probably a question for suspension engineers, or at least QA1 technical support. OTOH, the MII coilovers aren't a 'true' coilover (IMO), because even though there are collars on the shock body for the lower mount, the upper spring loads act on the MII upper spring mount / hat, leaving the shock's upper mount to handle normal shock absorber loads, plus some lateral forces as the spring acts on the lower mount.
I have no idea why CR decided on this extended upper mount approach, other than the ability to get greater travel through a longer shock body. My OEM MII front end uses the original upper mount and QA1 MS301 coilovers and I certainly don't have this problem - though it is a bit of a PITA to work on.
Restoring the upper mount to the original MII mounting configuration (or similar) is an option. The upper mount extension could be cut off and replaced with a plate that provides a replacement upper mount much closer to the spring hat. Whether that's done through welding or a bolt-on plate would be up to you. It needs to be strong enough to handle normal shock loads, not the weight of the vehicle - but location relative to the enlarged hole and the shock stud is important - you don't want it shifted and start inducing additional side loads beyond the original design. You'd also need shorter shocks than you have.