OK Guys…
I’m getting ready to change my 93’ Accord from R-12 to R-134a. The system sprung a leak and all the refrigerant blew out in short order. I have located the leak, and plan on fixing it, and getting the entire system repaired and ready, then have a shop vacuum it down and re-charge (I don’t have a vacuum pump). Here’s what I plan on doing:

-Fix the leak
-Drain old oil from compressor and evaporator and condenser
-Remove old Expansion Valve, and Filter Dryer
-Flush system w/ mineral spirits (except compressor?)
-Replace all O-rings w/ HNBR O-rings that have been lubed w/ NYLOG
-Install new Expansion Valve, and Filter Dryer
-Add new Ester or DEC-PAG lube to system? (about 120cc)
-Put R-134a adapters on R-12 High/Low Schrader valves


Do I need a new/different high pressure cut-out switch? (Since I’m switching to R-134a) Should I add the new oil, or have the shop do that? Where should I add it? Should the compressor be flushed? (I’ve heard not to flush it, just drain it)
I wouldn’t worry about flushing the system except it has been sitting open for about a year now.
Let me know if there’s anything I’ve forgotten or mis-ordered

Thanks!
1993 Honda Accord, Automatic, 120K

 

Anybody?

 

I agree w/ your plan w/ a couple of exceptions:

Use laquer thinner rather than mineral spirits. It evaporates much easier and is better cleaner. The evaporator is difficult to clear of mineral spirits by flushing, however vacuuming will remove laquer thinner for sure.

System originally used PAG. Suggest using the double-end capped PAG. I've used both ester and DEC PAG w/ good results so far. Check ackits.com for this item.

You may want to buy your own vacuum pump. You'll pay for the pump w/ the savings from shop fee for evacuating and recharging. Buy a 30-lb cylinder of R134a and you're set for many years.

good luck

 

Johnsen's FREEZE 12...it's SNAP approved and cheap too.
Works as well as R-12. I've used it several times with great success.
No hassle of changing fittings, oil, or flushes.
With your 134a conversion you'll lose approx 10 degrees, because cars with 134a from the factory have a larger condensor area.
134a is a smaller molecule and will find any chance to leak.

 

Thanks for the advice TexasHonda

On your recommendation I'll use Laquer Thinner, and I've corrected my original question (added DEC-PAG) I had planned to use it....oversight.

I figured that my process would be mostly right...I really need to know the answers to these questions though...


-Do I need a new/different high pressure cut-out switch?

-Should I add the new oil, or have the shop do that after vacuuming? Where would I add it?

-Should the compressor be flushed, or just drained?

Thanks!

 

No, you don't need a high pressure cut-out switch. You already have one in the system. Honda's have always had a combined hi/lo pressure cut-out switch.

You can add the new oil to compressor and/or receiver/drier, and/or condensor. Receiver/drier won't hold all of it and neither will compressor. Add as last step before closing system. Slight risk that vacuum check may show a leak, and require another repair at the shop.

Just drain compressor. You can get most of it out by draining.

good luck