Remove expansion pipe (orifice)

Clean the joint thoroughly

Remove the union nut

Pull or wiggle the expansion pipe out ( it is not threaded). Take care not to break off the expansion pipe. Make sure the whole unit is removed. 

Inspect expansion pipes (opening's) filter section

If the filter is choked or there are a lot of metal particles in it (refer to illustration) then the compressor may be in poor condition and need replacing with a new unit.

A rule of thumb: If more than 3 of the 5 filter sections are clogged (Fig. B) then the compressor oil should be examined. If the compressor oil is black and heavily contaminated, or if the compressor is dry, then replace the compressor with a new unit. Fig A shows an orifice that is normal.

After inspection the old orifice should be scrapped. The conversion kit contains a new one.

If the compressor must be replaced:

The new compressor unit as a replacement part is filled with mineral oil. Empty the oil and replace with ester oil (200 ml 6.76 fl oz) form the conversion kit

Warning! Do not fill Receiver with oil if replacing the compressor.
Only fill the compressor using the filler plug not through the inlet or outlet connections.

Note! The O rings on the compressor inlet and outlet must always be replaced with new ones
These Rings are not included in the kits and must be orded separatlly

For compressor replacement refer to the Service Manual Section 8 (82-88) Body Fittings, Interior, Climate Units 740, 760 1982-19... 

[Paul Spasske] If NOT replacing the compressor, fill the Receiver with the specified quantity of ester oil and leave the mineral oil remaining in the compressor. The mineral oil will not mix with R134a and circulate through the system. What is left will stay in the compressor and continue to lubricate it. The ester oil WILL mix with the R134a and lubricate the whole system.