slightly different forces there, compression vs expansion, also, the spring is designed to support the car through bumps and cornering... the jack only has to lift it in a stable state... and it often tips over.
if the rod is the same structure and width as the spring compressor rod, I'd agree it's capable of the job, but keep in mind, the spring compressors have a steel sleeve with locks on it for if or when the rod breaks...

Guys, you can get the rod at Grainger for less than 20 bucks... if nothing else, then it's worth it to not dissect a good jack. No?

I paid $10 for the same Mercedes Jack that came with the Car at the Junk Yard and apparently a lot of people onwn Parts Cars so it might be Cost effective.

I have no plans to disect any of my Jacks.

Despite the fact that the Car hangs on the threads of the Stock Jack I would prefer a thicker piece of threaded Rod; unless the Rod is thicker tan I remember.

My 82 Volvo also uses a similar Jack.

Admiral, I have to ask, how did you cut the spring seats out if you didn't have a spring compressor in the first place?

The $64,000 Question
 

The $64,000 question (Drum Roll) and the Envelope please..........:D



Charlie

I can offer my experience with removing the spring without a compressor, but it may not be how the OP obtained the spring seats he used. I was scrapping a car (123 front and rear damage), and needed the front end parts. I just did it "junk yard" style, and took everything off that was keeping the spring from extending (shocks, upper ball joint etc). I then took a big pry bar and pried the spring out of it's resting place. Yes it did fly a couple feet away, but I knew it would happen. I just made sure I was out of the path of it. It was not as big of a deal as I thought it was going to be, as the spring was almost fully extended (LCA at about 45 degree angle).

Whether or not it's how the Admiral did it isn't relevant to me. I want to know how I can do it! Good info!

Putting the car on jack stands and using a jack under the LCA will allow the removal of the upper BJ, and the shock. Lower the jack, and pry the spring out. It's just that easy. Be safe though. You could also run a length of wire rope through the spring and around the crossmember and clamp the ends with a cable clamp. That would keep the spring from flying across the yard. You could also place some sort of pillow and/or blanket inside a trash can that would catch the spring.
I needed the parts to rebuild, so I could just install new parts (new BJ's and LCA bushings) in them for the 123 front end I was rebuilding. That way there was not much down time on the car.

Could it really be that easy to get the springs out? What about getting them back in? I am intrigued by this idea as I am about to do ball joints and control arm bushings.

Easy to get them out without a spring compressor, IMPOSSIBLE to put them in without a spring compressor.
Check out:
http://www.peachparts.com/shopforum/diesel-discussion/332997-123-suspension-front-end-rebuild.html