I bought the flush gun kit for $30 on EBay - do a search and you should see them.

At the same time I also bought a quart of FJC flush solution on EBay. After getting into the job, it was obvious that more than a quart would be required. In searching around some I found the best price for what I wanted (gallon size) was on Amazon. I used the quart just to clean out the compressor manifold lines (short line to condensor and half-line towards evaporator valve). Don't forget that there is an O-ring near the brake booster (on the 300SD) where the manifold line joins with another short line into the evaporator - if you are replacing O-rings this is a good one to get.

A gallon is probably good to flush a system that does not have debris inside (from a failed compressor) and is marginal if you are changing refrigerants (and thus the oil type).

Paying $30 for a convenient way to inject flush solution is worth it to me. The pressurized gun allows me to flush solution UPHILL and thus fully saturate the hose being flushed. When you flush downhill you might not fully flush the upper 1/2 to 1/3 of the flat sections of hose.

Ken300D

__________________
--------------------------
1982 300D at 351K miles
1984 300SD at 217K miles
1987 300D at 370K miles