A/C system - how to remove the cooling unit, evaporator, expansion valve (9 Viewers)

[flintknapper]

I went ahead and ordered the new line. I decided that after spending all of the time and money that I have sunk into this junket, cheaping out at the last minute was dumb. I will probably just pull the booster as I have been wanting to paint it anyway and toss in the new line next weekend.

That's my man! Repairing the other line (because of where it was)...was going to be a screaming B#tch anyway.

 

[Will Van]

I replaced my A/C compressor and tried to pressurize the system. With the motor running my high side was increasing pressure, but the low side wasn't going up in pressure. My mechanic said I needed to replace my expansion valve, then try again. I pulled the evaporator, and found a few interesting items.

First, I think my ECU was replaced at some point. My truck is a 3/93 manufacture date, but the ECU is labeled 5/94.

Also, this plug was disconnected from the evaporator unit. I noticed the disconnected pigtail before I even pulled the unit out of the truck.

I think it's for the ballast resistor that controls fan speed, but I'm not exactly sure. As far as I can remember, the A/C was working fine until the compressor seized.

I've cleaned all the leaves out, but I'm wondering if I should just go ahead and replace the evaporator core while I'm doing the expansion valve. RockAuto has a Denso unit in stock, so I think I'm going to go ahead and order it. What do you guys think? Does the evaporator need to be replaced?

 

[ZackR]

If the evaporator isn't leaking or damaged you can clean it out and reuse. I used some orange cleaner spray and a bunch of hot water in my kitchen sink (with the inlets taped closed). I let it soak in hot soapy water for a while and rinsed it out.

 

[Red Merle]

I replaced my A/C compressor and tried to pressurize the system. With the motor running my high side was increasing pressure, but the low side wasn't going up in pressure. My mechanic said I needed to replace my expansion valve, then try again. I pulled the evaporator, and found a few interesting items.

First, I think my ECU was replaced at some point. My truck is a 3/93 manufacture date, but the ECU is labeled 5/94.

Also, this plug was disconnected from the evaporator unit. I noticed the disconnected pigtail before I even pulled the unit out of the truck.

I think it's for the ballast resistor that controls fan speed, but I'm not exactly sure. As far as I can remember, the A/C was working fine until the compressor seized.

I've cleaned all the leaves out, but I'm wondering if I should just go ahead and replace the evaporator core while I'm doing the expansion valve. RockAuto has a Denso unit in stock, so I think I'm going to go ahead and order it. What do you guys think? Does the evaporator need to be replaced?

Looks like your truck had the ECU replaced with the updated version since the '93 was a known dud.

As for the evaporator goes, I am now in the replace everything camp as cracking the system open is a pain. The Denso unit from RockAuto appears to be identical to the OEM unit. You already have it apart. Why risk an issue? You could always clean the old one up and keep it as a spare. Keep the little cap thing that the new one comes with and put it over the holes before you clean the outside.

 

[Red Merle]

That's my man! Repairing the other line (because of where it was)...was going to be a screaming B#tch anyway.

I was too focused on getting the truck back to running, but now that it is, I can just schedule the line for next weekend and be golden. I am sure the putty will come in handy for something else.

 

[Will Van]

Anybody know what this plug is for?

 

[Tedward]

Guessing it's for the Lexus climate control.

 

[Red Merle]

Guessing it's for the Lexus climate control.

The fact that it looks like they just nailed that on there makes me wonder about the Lexus version of these trucks.

 

[Will Van]

Guessing it's for the Lexus climate control.

The pigtail was present on my truck, it just wasn’t plugged in.

 

[White80]

Your evaporator looks much better than mine did. I cleaned mine originally as I somehow forgot to order one when I dove into replacing everything in the system. I gambled and 3 days later had no AC again. Ordered a new Denso up and had to tear back into it, yippee. Good news it works just fine now.

My leaky one prior to cleaning for reference...

 

[Will Van]

Your evaporator looks much better than mine did. I cleaned mine originally as I somehow forgot to order one when I dove into replacing everything in the system. I gambled and 3 days later had no AC again. Ordered a new Denso up and had to tear back into it, yippee. Good news it works just fine now.

My leaky one prior to cleaning for reference...

View attachment 1794954

Roger that. I went ahead and ordered a new Denso unit. It’s a pain to take apart. I wonder if I should do all new seals too.

 

[BigAxeJack]

Anybody know what this plug is for?

I'm pretty sure that's the blower motor resistor. It enables fan speeds 1,2,&3. Full speed (4) will work whether the resistor is in line or not.

 

[Red Merle]

Made further progress today. The new line came in and I managed to snake it in without breaking it but I had to remove the brake booster and loosen the main wiring harness from the firewall, loosen the heater valve and also pull the hose off the metal pipe that is on top of the PHH, and then a bunch of stuff over on the driver's side fender. I got it in, but it took some wiggling. The old one was shot. I wasn't aware aluminum could corrode like that...

I took the opportunity to paint the brake booster as I hadn't noticed that it was raw steel when I installed it. I remembered how finicky the push rod was so I tried to keep it so the portions that mate with the gaskets for the master cylinder and the firewall remain the same thickness. This was my solution. The rubber cap over the push rod is a shipping cap for an OEM radiator. It's a perfect fit and it seals the push rod area very well. Then I tossed on a new gasket and traced around the tape that I layered over the plug so that the master will be in the exact same spot as it was before without the extra distance that the paint would have made. The back side was a bit more generous, but the mini pail taped to the general area is fine, nobody will ever see that again unless the booster fails and then, who cares?

I am pulling a vacuum right now and plan on charging the system in the morning if the vacuum holds.

 

[Red Merle]

I finally got this finished(I think). It held a nearly 30 inches of mercury vacuum for 9 hours and then I filled the system. I am slightly worried that I added too much refrigerant though. The first 12 ounce can seemed to take for ever to enter the system but the third can went in super quick. I know I lost a little bit with a couple of errors with the stupid valve thingy that I had to buy but I may have a couple too many ounces over the 30 ounces I was shooting for. It does blow cold though and it seems fine. I am debating taking it somewhere where they can fill this more accurately though. I really wish I could have used the manifold gauges for this.

Any thoughts?

 

[Dissent]

I finally got this finished(I think). It held a nearly 30 inches of mercury vacuum for 9 hours and then I filled the system. I am slightly worried that I added too much refrigerant though. The first 12 ounce can seemed to take for ever to enter the system but the third can went in super quick. I know I lost a little bit with a couple of errors with the stupid valve thingy that I had to buy but I may have a couple too many ounces over the 30 ounces I was shooting for. It does blow cold though and it seems fine. I am debating taking it somewhere where they can fill this more accurately though. I really wish I could have used the manifold gauges for this.

Any thoughts?

My gauge just added to my worrying and over analyzing. LOL. If you're happy with the outlet temp, you're done. An oz either way may make a difference but charging to spec is what the dealer does and you are about right given the dosage of each can and the spurs swapping cans and what not. Enjoy your cool air!

 

[Red Merle]

My gauge just added to my worrying and over analyzing. LOL. If you're happy with the outlet temp, you're done. An oz either way may make a difference but charging to spec is what the dealer does and you are about right given the dosage of each can and the spurs swapping cans and what not. Enjoy your cool air!

I am going to roll with it for now. It's 40 degrees F here now. Winter is well on it's way and it never gets real hot here. I was only able to get it down to 42 degrees F today, but I could tell that it was doing it's thing. The pressure gauge on the POS valve jalopy was at about 40 PSI and was in the "green zone" on the gauge when the compressor kicked in and it dropped a bit when it kicked off.

If it's not up to snuff in the spring, I will just have someone do it or try to solve the fitting mystery so I can use my gauge set.

At least everything is new, installed and I know it doesn't leak. If I need to hire a gauge whisperer to get it dialed in, so be it. I can't imagine that would cost a fortune.

 

[weqster]

Hey guys. Im trying to diagnose a AC clutch not engaging in my hzj75 1hz troopy. I know it has pressure and doesnt leak and it was ice cold before this happened. Symptoms before failure was clutch was cutting out due on hot days i assume due to heat (had radiator problems) until it just cut out and never came back. So i suspect possibly its a low side pressure switch / temp switch related. Im trying to diagnose things without pulling the entire evap out, i can see the AC amp, and some connectors off it including this one that goes into the evap unit

https://forum.ih8mud.com/attachments/100_2454-jpg.343696/

I dont just want to start jumping wires.

https://www.landcruiserclub.net/community/attachments/a-c-circuit-jpg.31071/

Anyone able to help matching a plug to this wireing diagram?

 

[The Jade Bean]

Just referenced this and it was SUPER helpful! Thank you!

 

[alia176]

Awesome, glad to hear it amigo. Stay cool. One of these days I'm going to buy some beans from you.....one of these days....

 

[96LXtech]

Finally, two pics showing the removal of the A/C Dryer. This is a must if you're opening up the system and changing out the expansion valve.

Best access to the dryer is through the driver marker light. Tip: loosen the top two 10mm bolts first before opening up the bracket. These two bolts will very tight and will make the dryer move around on you unless it's still securely attached to the vehicle.

The FSM states to add 10 cc of PAG 46 oil to the compressor when replacing an expansion valve. Pay close attention to the FSM in regards to how much oil to add to the compressor when a A/C component has been replaced.


Well, that's all I got for now. Remember to re-install with brand new O rings by coating them with compressor oil first. These are metric O rings and not found in the typical auto stores unless special ordered.

I'll post up more pics of the evac and recharging process later today.

Thanks.
View attachment 343719View attachment 343720

Where did you add oil?