Typical A/C overhaul parts?


New Member
Mar 30, 2005
Thinking about reactivating my '90 5.0's long-dead A/C for the summer. I assume that a new compressor is gonna be on the list, but what else are the typical replacement parts I'm gonna need? I went through it on my Chevy, and it required a compressor, orifice tube and dryer canister (which ran about $400), but I believe that Ford used a different system -- true? What are the parts that usually need to be replaced on a dead Ford system?
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Reciever dryer - it is the aluminum canister on the firewall. It absorbs moisture and has absorbed all it can absorb & needs to be replaced. Cost is about $75.00

O rings - an O ring kit to match the new oil/R134a refrigerant is about $15.00

See http://jrichker.stangnet.com/Mustang_tech/R134a_conversion/R134a_conversion.htm for R134a conversion help since you can no longer purchse Freon (R12) in cans anymore, and will need to convert to R134a.

See http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=2435 is the A/C charging gauges that you will need.
Before you do ANYTHING put some (1/2 can)134a freon in the system. Put a leak detector to the system (can buy a used at a pawn shop or eBay). Check mostly near the connections and near the evaporator area (next to the heater core). Lift the seal around the evaporator tubes. If the leak detector beeps like crazy- bad evaporator. What happens is the leaves act as acid and crap stick on the evaporator and corrrode the evaporator- causing leaks. Now is the time for a new heater core. When you replace the parts- do the dryer and o- tube (or called liquid line). I would not replace the compressor unless it makes knocking sounds or your high pressure port on back of the compressor poped because of too much pressure. If it did -likely the front seal on the compressor wont seal again and leaks. Basically FIND a GOOD HONEST A/C guy.

If you convert it replace the parts- flush the system. Put Castrol pag 46 with dye in it (8 ounces- put 4 ounces in the compressor and two in the dryer and 2 in the condenser). put 134a retrofit fittings on it. Also best to replace all the o-rings. Vacuum it down. Put 2 1/2 cans of 134a in it and make sure your clutch fan is working properly.
nice job on helping him out, but everyone forgot that you must have the system in a vacuum. vacuum the system 30 minutes mininum and up to 4 hours depending on how long it has been exsposed to open air.

yes O rings for R-134a like he said.
Everyone missed this step (with the exception of Puter) :D

If your converting from R-12 to R134a you will also need to adjust down the low pressure cut out switch (it sits on top of the accumulator). It needs to be adjusted down to 18-19 psi. Remove the connector from the switch and turn the adjustor screw about 1 full turn counterclockwise from its factory position. (counterclockwise is less psi, clockwise is more psi, 99% of the time).
89 Saleen#455 said:
Everyone missed this step (with the exception of Puter) :D

When I researched 4 years ago, it was ~21PSI (Factory R12 setting is ~25PSI). First I heard of setting it down to 18-19. This is even with an approximate 85% charge (the stock system calls for 42 ounces of R12). I can see that it would not turn off the system as soon as it would, thereby keeping the refrigerant compressing and flowing.

*note to self*
I really need to update that webpage.
PuterAmI said:

When I researched 4 years ago, it was ~21PSI (Factory R12 setting is ~25PSI). First I heard of setting it down to 18-19.

21PSI will get the job done as well. You know how automotive A/C work's......trial and error....more trial and error.....flush the system, replace the accumulator, pull a vacuum....more trial and error :)