HELP please: What to do with a situation NOT in the service manual, NOT in parts list etc?

I am quite stuck, and in need of some wisdom.

CONTEXT

• 2011 Gen3 Prius. I am replacing the sway bar bushings (see Mendel's shared PDF, pp 37-38)
• To remove the LH bushing requires (according to service manual) removing the LH Front Lower Suspension Arm (attached to the Front Suspension Crossmember), and the Front Suspension Member Front Brace, which is held on by four bolts.

A Not-So-Tiny Problem

• Unlike other generations of Prii, this one isn't as simple as described.
• The right side, I didn't even need to remove the control/suspension arm, just the "Brace."
• The left side? Auuugh! One of the four bolts is NOT held in by the metal it bolts to. It has a hidden nut.
• Please see photos below...

I assumed I could access the nut by removing the LH control/suspension arm. WRONG.

• Said nut is inside the Front Suspension Crossmember!!!
• Said nut is NOT listed in the parts diagrams for my car
• Nor is there any explanation of how to grip it to install or remove the bolt that holds the 'brace' for the sway bar bushing.

I need ideas, experienced input, wisdom.

• How can this be? (My guess: perhaps the nut was originally tack-welded in place?)
• Any ideas how to hold the nut through the lower suspension arm bolt hole, for removing and later re-installing the wayward front brace bolt?
• Is there any recourse with Toyota for such a hare-brained design???

In the photo:

• Above: the front suspension crossmember...
  • With slot for the control arm bushing...
  • And holes for the control arm bushing bolt, inserted on left.
  • The hole is 14.5 mm
• Below: you're looking at the Front Suspension Member Front Brace, held in place by just one bolt, aiming (upward) into the bottom of the Front Suspension Crossmember
• (Off to the right is the sway bar)

Photo below: taken with USB cam inserted into the 14mm suspension arm bolt hole in the side of the front suspension crossmember. You're looking at a 17mm nut.


I am stumped at this point.

 

Great questions...

Yes, absolutely spins. And yes, confirmed it is loose in there.

I kinda assumed I need to remove more stuff... but don't see what can be removed that would help: that big hunk of metal is all one part on a Prius! It is the Front Suspension Crossmember.

Yes, I have a powerful impact gun. My next step is going to be to use the bolt hole to squirt some penetrating oil on the nut and wait a while for it to work.

I do own a right-angle crowbar. Not sure I can get it to fit in there, but something like that may help.

My other thought is to use the magic of modern chemistry: perhaps there's a super strong adhesive I can squirt in there to hold the nut... or perhaps to fill the space between the nut and the side of the metal box, and keep it from turning?

Pretty sure I could:

• Pull down on the bolt and spin, causing the nut to grind a bit and create a relatively smooth mating surface between the nut and box
• squirt anti-adhesive into the bolt hole to protect the bolt-nut connection (grease?)
• then squirt a thin super-strong (epoxyish?) adhesive around the outer edge of the nut, using capillary action to suck it into the mating metal-metal surface. Idealized result: nut is bonded to the box, and bolt is free to turn...

Yeah, in my dreams

 

The job is done. Whew...

Here's what I ultimately did:

1. I have no piece of metal rod that can work it's way to jam against the nut.
2. I am cautious about integrity of the metal car frame...

3. I tried one more time simply using a crowbar to provide pressure, and my torque gun ($99 Hyper Tough High Torque #80287, 3 year warranty FTW!)

Result: there was a little more movement, enough to carefully spin the plate out of the way and replace the sway bar bushing!

4. Stared at the puzzle for a bit, and chose a mechanical solution for tightening the bolt... I tightened the plate-body connection instead of the bolt-nut

5. Inserted two stainless sell washers next to the wayward bolt, filling the gap between plate and body.

Tightened everything down, and it is solid.

NOTE: the plate is already compressing a bushing that more than fills the available space. I seriously doubt I have added any real risk.

 

Meee too!

The only thing I can think of is that the nut was supposed to be welded in place. A bad weld there would only affect those who try to replace the sway bar and/or bushings.... Thus i am curious how many have changed the sway bar bushings.

Once I am driving again, I am also curious whether the new bushings will reduce the noisiness at all.

After this set of updates and upgrades is complete, I hope nothing else.

Fortunately, while it has been a lot of calendar time, the clock time hasn't been toooo horrendous. I am not at all retired, so the rest of life keeps me more than a little booked.