My 2005 Impreza Outback Sport spent its first 9 winters in Northern Pennsylvania before I bought it. I already replaced the front subframe because it was rusting out. My concern is a couple of areas of the rear suspension that have heavy surface rust and a little flaking off.

 

I wonder if this is compromising the structural integrity of these components at all, as I hope to keep this car a few more years.

 

I attached the some pics as files and are at the Dropbox links below.

 

 

 

 

https://www.dropbox.com/s/e9xvo5n5jrttvxd/IMAG0650.jpg?dl=0

 

https://www.dropbox.com/s/frkkbzan74efzrf/IMAG0651.jpg?dl=0

 

 

Tap it with a hammer and see if you can poke a hole through. 

I tapped it with a pick hammer. Some more metal flaked off, but there is still some solid metal there (not sure how thick). Hoping I can get at least a couple more years out of the car.

That's the rear subframe. I wouldn't trust that to hold up much longer. It's not exactly substantial to begin with.

 

Find a whole rear end from a junkyard car. Try Car-part.com.

I am no pro ,  But i have 18 years with the DOT in CT,   Working with plow trucks,i see a lot of rust.  One thing i learned is just how strong a little piece of steel really is ,   ever cut up a old truck frame with a torch ?  a little stran of steel left uncut can hold lots of weight..  car has seen 10 harsh  winters and its flaking some.  now you are taking car of the car      that can be perforated like swiss cheese and still will hold..     you know its their,keep an eye on it,  to me that will last another 10 years easy.    paint it with encapsulator  paint if you want to help preserve it.

In my opinion that frame will last for many more years

Knock off the loose stuff, apply Waxoyl or similar penetrating /greasy undercoat.

I am no pro ,  But i have 18 years with the DOT in CT,   Working with plow trucks,i see a lot of rust.  One thing i learned is just how strong a little piece of steel really is ,   ever cut up a old truck frame with a torch ?  a little stran of steel left uncut can hold lots of weight..  car has seen 10 harsh  winters and its flaking some.  now you are taking car of the car      that can be perforated like swiss cheese and still will hold..     you know its their,keep an eye on it,  to me that will last another 10 years easy.    paint it with encapsulator  paint if you want to help preserve it.

In my opinion that frame will last for many more years

 

 

this. mines much worst than what u have and is still holding things together just keep an eye on it.

There are people selling rust free or minimal rust rear "boxes".

 

I know up here these 1995+++ , 2000++++ cars seem a lot worse than those previous for that rear box rot and rot in general. Hence the guys peddling solid boxes.

 

Good luck with it.

That's the rear subframe. I wouldn't trust that to hold up much longer. It's not exactly substantial to begin with.

 

Find a whole rear end from a junkyard car. Try Car-part.com.

 

The fun starts when you try to replace it, because out of the 4 big bolts that hold that subframe to the body, at least one will snap off or take the threads out of the captured nut in the body. Unless you can poke a hole in the subframe, leave it alone because the job quickly turns into a massive headache.

 

If you have a good compressed air supply, buy a needle scaler http://www.harborfreight.com/air-needle-scaler-61447.html to blast the rust off, then coat it in good paint. That will buy a couple years.

My 96' Impreza have literally the same exact rust, to the same level too. And at least on my car, it's nothing to worry about. Unless you can put finger through it or push on the mental and a whole piece flexes, you're probably fine.