Hello everyone I bought an 84 fiero back last December and found the motor was junk locked up and rusty all over the cylinders and wouldn't move but in the process of taking the rear subframe out we found that the nuts on the rear mounting part of the cradle had rushed off and broke. I'm sure I'm not the only one to experience this and was wondering how people got around fixing this and mounting the subframe. Thank you

Holes are made in the frame to access the nuts.

Cradle nuts

[This message has been edited by Patrick (edited 06-14-2025).]

i understand if you remove the rear bumper you can access them.

Yeah, wanted to foot stomp this...

They are called "cage nuts," and they are typical for a lot of GM cars of the 70s and 80s. What happens is the "cage" inside the frame rusts out, and then there's nothing to keep the nut from spinning... so you can't remove the bolt, obviously.

In the Fiero, some people cut holes in the frame... I definitely do not recommend this.

Easiest way to get to them is to remove the rear bumper... it's really not THAT hard... follow this process:

1 - Remove rear tail-lights
2 - Remove screws in the rear wheel splash shield attached to the rear bumper.
3 - Remove the rear red parking lights on the side (torx scxrews). Then remove whatever other screws you see there.
4 - Remove the rear bumper... held on by a couple of clips that pull out.
5 - Remove steel bumper

... you'll then be able to actually fit your hand in there. I have massive hands... and I can reach my fingers in there... but either way, youl should be able to fit a tool in there, or even a welding tip if you want to spot-weld the nut in there.


Here's a video of my daughter removing the rear bumper cover and tail-lights. She's actually removing the whole subframe too, so it might be helpful:




Here's a video of my daughter re-moving the steel bumper underneath, and you can see access via the frame rails where you can access the cage bolts:

Thank you that should help a lot!