W123 rear sub frame
I have a 81 w123 Estate which I removed and am just finishing off refitting my rear sub-frame assembly, (see post Pig bolts ). The first question is, is it only the sub frame mounting bushes you wish to change, if so according to my manual you can do this without dropping the sub frame. In my case it is part of a full renovation so it had to come off to service all the parts fitted. One serious thing I did find once the sub frame was removed was the large amount of surface rust , on the frame being heavy duty it cleaned of easily and was repainted. The much more serious was the rust on the petrol pipes (mine were close to going through )and so were replaced, this seems to be a moisture trap.
When I dropped my sub-frame down I did it on a trolly jack under the diff, while the front was supported on axle stands, once the back end was down I man handled the front off the stands, not easy, especialy single handed,(I would suggest assistance if possable). Also when I came to replace the frame I made a wooden cradle to fit the diff snuggly, which made the lift much easier and more controled, which had I known before I started I would have made/used for the drop.
To support the rear of the car while the frame was off I put my HD axle stands under the rear sill jacking point, but to be sure nothing could move while manovering such a big heavy lump from under the car,I welded 1.25"x0.75" tube to the top of the stand as there is a convenient hole just to the rear of the jacking point ( covered with rubber bung).One last thing, after I dropped my frame, I found the gap between the base of my axle stands was 0.5" too small, so had to stip it under the car. Sorry to waffle on, I somtimes don't know when to stop, if I can help in any other way please get in touch direct.