Replacing A/C compressor after R134A conversion help

[bruce119]

I took my 93X truck to the shop for the conversion to R134A. They did it but said the compressor is a little weak and rattling a little. There not sure how long it would last. It doesn't blow as cold as it should and they said the pressures weren’t quite were they would like them. They said the good thing is that the conversion was done so that wouldn't have to be done when it came to replace the compressor.

Now I can turn wrenches. My question can I replace the compressor myself. I was looking at the Auto Zone # 618132. It doesn't look that bad I would think the system would have to drain and refilled?? What else would I have to do or should do I want to keep it as low cost as possible. Can I drain R134A myself and then fill it back up with a kit. Suggestions or recommendations are appreciated.

Thanks

 

[arco777]

Conversion to R134 requires replacing the compressor anyways. It is easy to change yourself, just undo the serpentine belt, remove the fittings and unbolt the compressor. Make sure the new compressor is spec'd for R134. Also check if it is pre-filled with compressor oil, otherwise you need to buy oil and oil the compressor before installing.

That said you will still have to drain the system and refill it.

It's illegal to vent freon into the atmosphere so you have to "recover" it by sucking it out. Then the system needs to be put under a vacuum - you don't want ANY air in it. Then you can fill the system with the proper amount of refrigerant. Best to let the shop do all this. Of course if your system comes in to the shop empty of freon (not that I am advocating venting it yourself) you can install the compressor and other parts yourself and then the shop can charge up the system.

It is possible to charge a system yourself from empty or to top it up when it leaks down. But for the cost of freon and the tools required it's usually more cost effective to have a shop do it. Also an empty system needs to be put under vacuum before filling it and tools to do that aren't cheap. You could just ignore that and charge it yourself from empty, but any residual air in the system will decrease its effectiveness. R134 is already not as good at cooling as R12!

Old R12 seals will not keep R134 in so every single one will need to be replaced with R134 compatible. Also you need to replace your drier (if it wasn't done already) or else it won't absorb moisture as it's supposed to. Replace your orifice tube too - it filters the junk out of the system like debris and bits of the old compressor tearing itself up. It's only a couple bucks so better safe than sorry even if it was already done.

 

[arco777]

If this is confusing let me know and I'll try to clarify stuff.

I should also mention. A remark like "pressures aren't where we'd like them" is suspect. I'd want clarification! Did they overcharge or undercharge it?

You can pretty easily tell on any Ford if the system is undercharged, simply by turning the AC on and watching the compressor. If it engages and stays on constantly, the pressure sensors say it's well charged. If it cycles on and off, it's low. The more time it stays off, the lower it is. Good tip for buying a used car!

I don't remember if the pressure sensors themselves need to be swapped out for R134 compatible ones, but their seals certainly would need to be.

 

[bruce119]

Well I am trying to save a few $$$. The shop did the conversion cost me $130.00. I did look at the dryer and orifice and a seal kit from A.Z. I may wait just a little bit but maybe the way to go is take the truck in get the system evacuated. Then do the work myself and take it back to get them to charge the system. I'll talk to the shop to get there opinion also. I just don't want to pay high labor charges when I can turn nuts & bolts.
Thanks

 

[arco777]

Well I am trying to save a few $$$. The shop did the conversion cost me $130.00. I did look at the dryer and orifice and a seal kit from A.Z. I may wait just a little bit but maybe the way to go is take the truck in get the system evacuated. Then do the work myself and take it back to get them to charge the system. I'll talk to the shop to get there opinion also. I just don't want to pay high labor charges when I can turn nuts & bolts.
Thanks

I agree, no point in having them bolt on things that you can do yourself.

As for the pressurized stuff, I tried (spent hundreds) on the tools and freon and oil and dyes and UV lights, and ended up learning it was far cheaper to have the shop do it. Learned the hard way about how to get a working AC system and do a R134 conversion (a $10 "retrofit kit" consisting of two fitting adapters is not the answer ).