Dadburned 124 Expansion Valves!

[jcyuhn]

Could use some magic advice from the forum.

The a/c on my '87 124 wagon went out a few weeks ago. Was on a long road trip and the front seal on the compressor failed. It let all the oil out, with the result that the compressor seized.

I completely disassembled the system, flushed it thoroughly, used dry air to blow it all out, etc. Acquired a new compressor, dryer, expansion valve, and nice green neoprene o-rings.

Put it all back together and I have a massive leak at the expansion valve. Disassembled, cleaned, and inspected that area, but it still leaked after reassembly. Is there some magic trick that I'm missing? Any advice, tips, tricks, voodoo, etc. would be appreciated.

- Jim

[Benzmac]

Actually I have seen professional techs have problems in this area. What I do is soak the o-rings in oil then install them. Next put a little drop of oil on the mating surfaces of the expansion valve before installation.

When you install, you will have to tighten the 3mm allens side by side at 1 turn each, alternating untill done. Then install the outboard pipes carefully making sure that they are fully engauged. Then tighten.

Good luck

[jcyuhn]

Benzmac - thanks for the input. I gave it another shot last evening, more or less as you described. I soaked the o-rings in a jar of oil, and oiled both the evaporator pipes and the expansion valve. It's much improved, but still did not seal completely. My sniffer isn't finding much around the front pipes, but goes crazy on the evaporator side of the expansion valve.

I probably didn't tighten the two 3mm screws like you described. Will try that next time... As well, the guys over at aircondition.com swear by an o-ring lube/sealant by the name of Nylog. Think I'll acquire a bottle of that too.

Ever seen an expansion valve itself leak right out of the box?