Time to replace my compressor

[Schurkey]

I'd expect that proper "green" o-rings can be used with R-12, but "R-12" black O-rings can't be used with newer refrigerants.

The "green"--if they're quality units and not bottom-feeder garbage--should be backwards-compatible.

 

[marshallsmith27]

Should I replace the spacer o rings on the manifold hose?

 

[Schurkey]

I replace ALL the O-rings. O-rings are cheap. Refrigerant is expensive.

 

[marshallsmith27]

Where did you read that? I've been using green ones for years.

I decided to just go ahead and deal with the headache of replacing everything and going r134a. I saw you mention on another post a while back responding to someone else that we need to wire in the HP switch. Well my truck didn’t have a HP switch and I have no idea where to wire one into the trucks wiring. The HP switch came with a two wire connector. my truck has the AC and recirc buttons. do y’all know where to wire in the new two wire connector? because I can’t find where to wire it

 

[marshallsmith27]

I have everything oiled and and ready to go I just need to vacuum the system and charge it but first I need to find out about this high pressure switch

 

[PlayingWithTBI]

The HP switch came with a two wire connector. my truck has the AC and recirc buttons. do y’all know where to wire in the new two wire connector? because I can’t find where to wire it

Cut one of the wires going to the Low Pressure Cycling Switch, and connect the ends to the HP Switch so it will be wired in series with the LPCS. Here's a schematic of what I did with mine (in blue). I used the Lt Grn wire but, it doesn't matter which one you use. It also shows where I added a relay to get full battery power to the compressor coil. You do have the HP Switch installed in the back of the R4 compressor, right?

You must be registered for see images attach

 

[marshallsmith27]

Yes I do have the HP switch installed in the R4 compressor.

 

[marshallsmith27]

I had to stop today because I realized I need the washer kit for this compressor and the parts store doesnt have one on hand but will be here at 7 am tomorrow.

Washer Kit

The new R4 compressor doesn’t line up with the manifold like the old one did.

I got some wire and split loom to wire the HP switch in series tomorrow as per your diagram.

I have never done an AC system before so I have my dad helping me and I have realized now that I could have done this myself with less of a headache not having him. This is not hard and confusing like I though it was. I have replaced everything but the evap coil and the manifold lines and the the line from the accumulator to the condenser. I dont want to do this again in a few years so I want it done right the first time without corner cut and rushed.

I have a question about adding the HP switch. If the old compressor never had one and never needed one? what is the exact reason for adding one to this new install?

 

[PlayingWithTBI]

If the old compressor never had one and never needed one? what is the exact reason for adding one to this new install?

Back when the old systems used R12, they ran on lower pressures and, had a "blow-off" valve which would release Freon into the atmosphere if the system over-pressurized. That is totally a no-no now! In the heat of the day, with R134a, if you shut off the engine for a while, maybe go eat lunch. It gets heat soaked to the point when you start it back up, it'll spike pressures up over 500 PSI. With the HP Switch, it'll shut off the compressor @430PSI (with the one I have) and turn it back on @200PSI until the system equalizes to normal pressures at ambient temps. I had an HP Switch blow out of the back of the compressor due to that, sounded like a shot gun going off! After cleaning my shorts out, I found the groove for the snap ring broke ruining my almost new R4 compressor.

That's when I started doing research. On the systems without the "Max" button they had a one-wire HP Switch, in the back of the compressor, that would close the recirculation door to help bring down pressures and stop freezing by bringing in warmer air.

So, my little work around is simply protecting the system from grenading itself again and, has worked great here in the desert with almost 120° ambient temps for almost 3 years now. HTH

 

[marshallsmith27]

That’s what I thought! I just got it wired up. Used split loom and ran it with the stock loom so you can’t even tell I installed it! We have been chasing a leak for the last hours and we finally realized it was the gauges/hoses. I am hoping we can get it charged with these gauges slowly leaking.