88 Toyo Pickup - rebuild ac system and flush questions

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murphtron
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88 Toyo Pickup - rebuild ac system and flush questions

Post by murphtron »

Hi,

newb here (of course). I'm rebuilding the AC in a 1988 Toyota Pickup. I plan to replace the following components with new ones and use R134a:

condenser, compressor, evaporator, dryer, TRX valve, and o-rings will all be replaced with new units.

Truck came with factory AC but the aluminum tubing (roughly 1/4" OD) from the evaporator to the dryer was missing. I just sourced this tubing from eBay. So how can i flush this, assuming it's not installed? Can I drip solvent through it?

How do I flush the 2 lines from the compressor? These appear to be in decent shape. Or should I replace them? If replace where can I source them? If I just remove and flush, do I just drop solvent through them?

I'm confused about the process of converting the compressor to R134 (it will be new). I understand that PAG46 oil must be used, but I don't understand how the fittings are different. What tools do I need to change the fittings, and how do I source the fittings? A link would be appreciated.

Also, it seems that new compressors do not have a manifold with the fittings. I just use the manifold from the old compressor with new seals?

Finally, I plan to rebuild this system and vacuum test it to ensure no leaks. But I'm not sure I really want to go through the trouble of filling it myself. Is my plan (flush tubing, replace components and pressure test) the right approach before taking to a shop and having the system filled?

I have the Toyota service bulletin that has the oil and R134 refrigerant volumes. http://tms.cleanautoalliance.org/documents/ac002t98.pdf

Thank you!
murphtron
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Re: 88 Toyo Pickup - rebuild ac system and flush questions

Post by murphtron »

Re the R12 to R134 fittings. Is this what I need? And what are the black ones for? And why are there two blues and two reds?

And should I install service ports in the compressor lines? One of the line appears to have a blue (low) service port. There is no red service port in the high line.
Last edited by JohnHere on Wed Aug 31, 2022 7:51 pm, edited 1 time in total.
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JohnHere
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Re: 88 Toyo Pickup - rebuild ac system and flush questions

Post by JohnHere »

murphtron wrote: Wed Aug 31, 2022 12:57 pm I'm rebuilding the AC in a 1988 Toyota Pickup. I plan to replace the following components with new ones and use R134a: condenser, compressor, evaporator, dryer, TRX valve, and o-rings will all be replaced with new units.
So far, so good, but note the following: The new compressor, if it contains mineral oil, must be flushed several times with the oil you intend to use—in this instance, PAG-46. The receiver/dryer (R/D) you install must contain desiccant that's compatible with R-134a. Tim at ACKITS.com, this site's sponsor, can help with the parts and supplies you need.
murphtron wrote: Wed Aug 31, 2022 12:57 pm Truck came with factory AC but the aluminum tubing (roughly 1/4" OD) from the evaporator to the dryer was missing. I just sourced this tubing from eBay. So how can i flush this, assuming it's not installed? Can I drip solvent through it?
I presume that you're referring to the tubing that extends from the condenser to the R/D on the high-pressure side of the system. You don't need to flush new parts (with the possible exception of the compressor as already mentioned) unless the tubing is not sealed—that is, if it lacks plastic sealing caps on each end. If it does lack the caps, flush the line using this tool from ACKITS.com: 43-4054 A/C FLUSH CYLINDER W/GUN, plus a suitable solvent available on the same Web site.
murphtron wrote: Wed Aug 31, 2022 12:57 pm How do I flush the 2 lines from the compressor? These appear to be in decent shape. Or should I replace them? If replace where can I source them? If I just remove and flush, do I just drop solvent through them?
I recommend replacing them with barrier hoses if possible. The ones you have now are non-barrier hoses and might leak with R-134a. Check with Tim at ACKITS.com for availability.
murphtron wrote: Wed Aug 31, 2022 12:57 pm I'm confused about the process of converting the compressor to R134 (it will be new). I understand that PAG46 oil must be used, but I don't understand how the fittings are different. What tools do I need to change the fittings, and how do I source the fittings? A link would be appreciated.
As you know, the fittings on your original R-12 system differ from those for R-134a systems and must be changed. Again, contact Tim at ACKITS.com for the correct parts.
murphtron wrote: Wed Aug 31, 2022 12:57 pm Finally, I plan to rebuild this system and vacuum test it to ensure no leaks. But I'm not sure I really want to go through the trouble of filling it myself. Is my plan (flush tubing, replace components and pressure test) the right approach before taking to a shop and having the system filled?
A system that holds vacuum is no guarantee that it won't leak under pressure, and vice-versa. If you don't have the proper equipment and know-how to do that part of the job yourself, I recommend letting a professional shop handle the evacuation-and-charging portion for you.
murphtron wrote: Wed Aug 31, 2022 12:57 pm I have the Toyota service bulletin that has the oil and R134 refrigerant volumes. http://tms.cleanautoalliance.org/documents/ac002t98.pdf
The referenced document differs from the specifications that I have for your truck, but I would go with what Toyota states. Of course, you'll substitute R-134a and PAG-46 instead of R-12 and mineral oil.
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Re: 88 Toyo Pickup - rebuild ac system and flush questions

Post by JohnHere »

murphtron wrote: Wed Aug 31, 2022 6:12 pm Re the R12 to R134 fittings. Is this what I need? And what are the black ones for? And why are there two blues and two reds?
And should I install service ports in the compressor lines? One of the line appears to have a blue (low) service port. There is no red service port in the high line.
Tim at ACKITS.com can help you with the correct adapters.

If memory serves, the high-side service port might be on the new line you're planning to install, near the R/D and sight glass assembly.
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murphtron
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Re: 88 Toyo Pickup - rebuild ac system and flush questions

Post by murphtron »

Thanks so much for the feedback! I'll contact Tim.

The parts I sourced on eBay are what's shown in this video starting at 0:32sec.

https://www.youtube.com/watch?v=OWDu8Feca8c

It's a 2-piece aluminum line that goes from the Dryer to the Evap unit. Not the short line from the Dryer to the condenser. It's used, not new. I assume I should flush it to be thorough. That make sense? That's really the only part (aside from the short line from the Dryer to the4 Condenser) which would be flushed, assuming I replace the two lines from the compressor. The rest of the system will be new.
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Re: 88 Toyo Pickup - rebuild ac system and flush questions

Post by JohnHere »

Right, I would flush the used lines, and dry them out thoroughly. Nitrogen is best for blowing through them, but if you don't have a nitrogen set-up, shop air will do in a pinch—the drier the better. The new condenser, evaporator, and hoses don't need to be flushed as long as they're factory sealed.

I see from the video that both the high-side and low-side service ports appear to be on the hose adapters attached to the compressor. The new barrier hoses (if available) might come with the R-134a service ports. If not, you'll have to convert the fittings on the adapters from R-12 to R-134a hardware as previously discussed and, if necessary, transfer the old adapters to the new compressor. By the appearance of the plastic caps, the compressor in the video appears to already have the R-134a service ports.

If you're unfamiliar with getting the right amount of PAG oil into the system, let's discuss that as well because it's very important to the longevity of the system.

One last comment concerns the TXV. If you can get an OEM (Denso) TXV, I suggest doing so. Some aftermarket TXV's have been known to give problems over the past few years. You don't want to have to do the job all over again should a "new" TXV prove defective.
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