(99 E320)
coincidentally, i was under the car doing similar just now. yeah, that has
happened to me several times with minimal trauma. since my car is up on jack
stands, i simply use the floor jack to support the inside (near driveline) of the
control arm. if you have wide, concave contact point on jack, just place a large
25+mm socket so that it will better fit that narrow end of the LCA...between
the two frame 'ears'. I drift the bolt out and lower the arm completely. the
shock etc holds everything else in place

the spring is compressed and simply falls out. I unload the tension and respace
the plates so that they're better positioned.

the trick with the Klann/clone compressor plates is how they are placed on
spring, they need to be spaced far enough apart for maximum compression,
yet close enough together so that when uncompressed, it wont touch the top
perch,nor will the plate touch the LCA. this may even take 2 or more tries.
compress spring to full lock

place floor jack underneath control arm. but do not jack up. this maintains
maximum space between top/bottom perch for spring re-entry.

position spring between perch. BE SURE you have the spring correctly indexed
into the perch....top spring pad, as well as the lower control arm. you'll see
little indents for end of coil.

with one hand, maintain spring roughly indexed. with other hand, slowly jack
up....and eyeing back and forth spring and jack. ensure jack and control arm
is lining up with with holes. you may need to gradully use diff diameter screw-
drivers (increasing diameters) to help hole align.

also, keep spring indexed so that when perch clamps spring, it'll be properly
positioned.

so you need to multi task as you raise the jack: 1) spring alignment,
2) maintain jack-to-LCA position, 3) LCA to frame bolt hole alignment

go slow and careful. it'll line up. much of the spring tension will be held
by compressor so lowering the control arm is a piece of cake. still, be careful
and move step by step methodically.

i've done this for my car 3x for each corner now, trying to get the look as I
swapped out spacers and springs over the past two weeks.

if you need pics, i can send to you that i've collated from various MB boards.
i studied these prior to jumping in and tackling this as a DIY. quite easy...more
of a tedious job than difficult.

__________________
-- raymond~
47º 34'N 122º 18'W