Learn me checking for bent unibody/Suspension

Dusterbd13 wrote:

Dashpot wrote:

Dusterbd13 wrote: Alingment shop claims subframe. Im not convinced. Local guy parts these cars out. Think im going to rip it apart and compare all the passengers side stuff to known good parts. I just cant believe that the subframe is the culprit. The parts guy in Concord says probably the bolt through the lca and upright.

I agree on the LCA long bolt. Only way to really know is drive that thing out & have a replacement on hand. Because you'll need a big hammer & will have a tough time getting that sucker out. While you're down there stick a straight edge across the inner LCA mounts to confirm they're not tweaked. They deform from the same hit that bends the long bolt at the other end. Good luck!

Where can i get the correct bolt? I know tractor supply will have something close, but.....

I ordered mine from Rosenthal Mazda when that was still a thing. I'm not sure if anyone has filled the same void or not. But Mazda still has the bolt available, so get it from your local Mazda dealership if you want the correct OEM bolt.

Google "Miata tub dimension sheet" and you'll get several sources of the underside locating points to measure the chassis for straightness. A metric tape measure will be good enough. A tweeked rear subframe isn't out of the question either. Just keep measuring components and attachment points and you'll unearth something.
Is this an NA or NB? I have a dimension sheet from the early NA factory manual that could be scanned and emailed if you need it.

Its a 2000 nb.

Unfortunately I don't really have a local mazda dealer. Nearest is about 50 miles each way.....

Ill call that one later and see if they have the bolt.

If toe is out on one side and not the other, it isn't a tub problem. The problem lies at the corner that is way out of whack. Further evidence is that the doors and such all open and close properly. Cars that are bent enough to mess with alignment... don't. Cars that have bent tubs, but not enough to mess with the suspension, have readily apparent fit problems.

In short, you don't have a tub problem.

It wouldn't be impossible for the subframe to get bent at the rearward control arm mount, but the bolt/knuckle is FAR more fragile and the more likely culprit.

Dusterbd13 wrote: Where can i get the correct bolt? I know tractor supply will have something close, but.....

Do the dirty work, make a list, then grab the whole control arm assembly from the local part-out guy. If it's just the bolt, get a new one from one of the online Mazda parts sites.

So, uh...  Whadya find?  And how did you end up finding it?

If I look at the rear suspension cradle I don't have a hard time seeing how the lower control arm pickup points could get out of whack. Just do a quick diagonal check

In reply to wvumtnbkr :

I THINK this ine was pinata. Which initially was bent control arms and a bent rear spindle. The next time it was totalled it bent the rear crossmember as well. So, the unibody,  though distorted for panel gap was fine for alignment with measurements taken based of tbe googled tub drawings. 

https://www.advanced-autosports.com/collections/tools

^they have a few jigs and tools to check the subframes and all suspension parts to see if they’re bent. Works wonderfully well