Best way to swap worn seat pads, springs for junkyd repl?
 

My drivers seat has a sunken pad and/or springs, and its seatback has a broken spring that's sprung facing Forward ('86 300E). So I bought an entire drivers seat (frame and all), from someone over the phone parting out a '90 300E. My original thought was to have someone do a straight swap w/it, replacing my entire existing seat w/the one from the '90.

But the parting out owner cut the bundle of approx a dozen wires at about 8" long from the bottom of the seat frame. I can see some backache or labor hours coming there... That bundle is wrapped up in some not very factory-looking fabric tape, don't know if that could be a sign of anything or not. And the back panel of its seatback is a different style than the originals in my '86, which have the shell w/web pocket back there; this replacement one has an upholstery pocket - is that what originally came on the '90 w/MB-Tex? I'm really hoping someone doesn't tell me this came from an earlier body style car.

Considering that I know everything electric on my existing seat does work, incl memory, what would be the best way to swap needed parts, leaving me w/good drivers pads and springs, and matching the look of the pasenger seat? I'll be paying hourly either a mechanic or auto upholsterer for this job, to save my achin' neck. What's the most time-efficient way to get me best seated here?

These are all Blk MB-Tex, so nothing great about having more of that facing the rear passengers. And I want both seat backs to match. I'd prefer to keep my 2 original seatbacks, I like that look better. My existing drivers back shell is on Tight, btw. I've taken out the 2 screws at bottom, and can't get it to budge, even when prying w/a thin tool.

I'm also thinking that if the covers on my original seat are going to be removed and replaced, then I'd order one of those aftermarket seat heaters and have that installed too, while they're at it. Like this one: http://v12uberalles.com/power_head_rest.htm

I would imagine with old padding and springs you are still going to have seats that sink down more than they should. You need to get the shell off the seatback somehow and strip down both seats. Then I would probably repair the broken spring in the seatback instead of replacing the whole thing, if possible. There are ways to clamp the broken ends together with metal tubing. Then pick the best pads to put back on. Give it a test sit. If it sags a lot you either need new springs, or do the pool noodle trick. You can recover the seat on your own but you might get lumps. A pro will probably do a better job, unless you have done it before.

Thanks raymr, sounds like just using just the parts of the replcmnt seat to put in my original seat is the best way.
--3 more Q's
1. If springs need to be replaced, does anyone ever take off the springs from the jnkyd seat and put them on another?

2. Who should I have do this job, an auto upholstery shop or a good indy MB garage?

3. Any good tricks to get my seatback shell off? It's never been removed (1986-2005), and feels like it's practically glued in.

repair seat frames and springs
 

Get yourself a c or hog clip and plier set at any auto supply store. You can repair the broken ends of the original springs, and clip some together to get a firmer seat bottom . These hold well and should rebuild any repairable springs. Work from there. good luck, Abe G

Broken spring fix
 

Another way that I have fixed broken coil springs in seats is to us the hard plastic tubing that Mercedes fits to washer systems etc.etc. Just cut a short piece of that and put each end over an end of the broken spring and push on ..... It works pretty well !! (perhaps metal tubing would work as well or better, as suggested in the previous comments) BC