Parts for 1983 300D/TD?
 

Getting the rear axle assembly and brakes repaired ... $600.+

Need steering assembly - it works but wanders a little - mechanic says $250. rebuilt using Benz-approved parts - sound about right?

Can we do cooling system and transmission flush ourselves to save some money?

Recommended kit of materials?

Thanks!

It is likely you already did what you listed.
My Opinions.
You did not say what was the issues with the rear axles. New ftermarked Axles have not shown themselver to be reliable.

In general there is no kits for most repair jobs. You order the parts individally.

Personally as long as My Car has no overheating issues and I maintain the proper Coolant strength I have never seen the need for Coolant Flushes.

If you have an Engine that has a lot of scale or rust in it doing a Coolant Flush often result in particles coming off for months and months that can plug Radiators.

Engines that have had perodic Flushes since they were originally owned should have no issues with particles plugging the Radiator because the system has been kept clean.

The Citric Acid Flush occaslonaly pushes corroded Core/Freeze Plugs over the edge and they leak. The same some of the other metal coolant system parts.