Anyone know what this thing is called? It appears to be some kind of frame brace, may be wagon specific to support the longer rear frame rails. It bolts on beside the gas tank with 4 M10 bolts into the frame. Seems to brace the bend where the frame straightens after the wheel well. It's pretty beefy. My 87 wagon only came with the passenger side one that was only held on with 1 bolt, making a helluva racket. Removed for now but looking for the driver's side and don't know what it's called. Googling rear frame brace brings up tons of aftermarket bracing, but not this part that I could find. Thoughts?

Also posted question on FB.

 

That looks like the bracket that is bolted to the frame rails and is aligned with the rear caliper extensions on both sides. Their purpose is when the car is hit (hard) from the rear they push the calipers and rear axle/differential forwards - preventing the gas tank from being crushed by the differential as the rear of the car crunches up (and avoiding the gas tank rupturing and catching on fire)

The "frame rails" are the same length in a sedan.

 

My man! That's exactly the part I'm talking about. Thanks for the explanation on their function.

Other than the obvious safety issue they are designed to prevent, any issue not running them if I cannot find a driver's side one?

Any idea what their Volvo name is?