80 series AC intel?

flintknapper

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Now that you mention another shop replacing the expansion valve but skipping out on the receiver/dryer there is a new concern. Every single time the A/C system is opened to atmosphere, moisture (water) enters the system. The only way to remove the moisture is to boil (evacuate) it out with a vacuum pump, holding a deep vacuum for 30 minutes or more. Any moisture left in the system is absorbed by the receiver/dryer and the only sure way to start with an "empty" dryer is to install a new one as the last step before sealing and evacuating the system. If the shop did not replace the dryer, I would question whether they evacuated the system before recharging with refrigerant. If they did not evacuate it, they also left air in the system. The interesting thing about air in the system is that it will lead to higher than normal pressures!

^^^^

This is almost certainly what happened (no evacuation or poor evacuation). Drier desiccant is saturated and at some point will break down and travel to his new TXV where it will clog the screen.

I have no doubt there is both air and moisture in the system.

OP has a 'roll the dice' situation on his hands. If he wants to clean parts, check for leaks and replace only what appears to be faulty, this can be done. But on an old system (and a person meaning to keep the vehicle) it is often best to just go through the system and be done with it.

Assuming the Compressor is good....then New Condenser, New Evaporator, New TXV, New DRIER, new Schrader valves. Flush all the hard lines and replace all O-rings using Nylog on the O-rings, mating surfaces and Schrader valve threads.

Pump the system down (using a REAL vacuum pump) check for leaks. IF no leaks are found then continue to pull a DEEP vacuum on the system for a full 2 hours (this is where shops get in a hurry).

Then recharge the system (now empty, clean and dry) with a 'weighed in' refrigerant/oil amount. This will get you in the ball park....and then you can 'fine tune' the charge to get those last few degrees of vent temps by using the gauges and watching the vent temps (adding or removing refrigerant). This is also something shops don't do.

Gentlemen.....A/C work is no fun (no way around it). It can be expensive and time consuming, so do you really want to do it twice or three times?

IF it can be avoided please do not use dyes or sealants unless you are just destitute and have to have semi cool air.

Those who live in hot climates and depend on their A/C 8-9 months out the year.....would be best served by refurbishing the SYSTEM even it that means collecting the parts before hand.

I understand financial constraints can dictate what a person is able to do and I am not suggesting that in every case the entire system needs replacement.

IF you have a system that is currently holding pressure.....then careful evaluation of any problems is the thing to do (to a point).

In the OP's case.....he has slightly higher than normal pressures (depending on the ambient temp at the time). There are several reasons this could happen. Insufficient air flow, dirty condenser and evaporator, air and moisture in the system and a saturated drier are almost a certainty in his case. We also have no idea the refrigerant charge or oil charge.

A good shop with the proper equipment and a 'tech' willing to take the time to evaluate the system could fix it with a minimum of parts being replaced, but good luck finding one of those.

A DIYer without much (if any equipment) and little understanding of how an A/C works faces a daunting task. It's not Black Magic and folks can learn (I encourage that), but try to avoid having to do things multiple times and don't cut corners when it comes to A/C work.

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From the pressure readings, it could be overcharged (anyone work on the system recently?) or another possibility is the fan clutch isn't doing it's job.
It's normal for the drier to be hot.
I'm not sure what replacing the expansion valve & drier will accomplish. Usually if the expansion valve is bad it either sticks open and the system pressures are close to the same or it sticks closed and the low side pressure goes to zero or into vacuum.
In any case, if you end up opening the system, I'd replace all the o-rings and schrader valves.
hey man,
a couple of follow ups please on technical questions and then a separate reply on your comments here about the expansion valve please?
can you help me with getting the technical numbers from the FSM and this sticker but also this "pressure temperature chart"?

1. sticker says range for "pressure in the system" (?)is 1.98 - 1.76 lbs? this is a weight? a force? do you measure this with the two dial manifold gauge? where are you measuring?

2. both the sticker and FSM say ND-oil 8 and FSM says 40cc/1.4 fl oz. this gets added if you remove the dryer or something? where does it get added?

3. FSM says refrigerant in the system (after a vacuum i guess) is 850g +\- 50g (29.98 oz +\- 1.76 oz)? where does this get added? also how do you know how much weight you have added if you have full cans of it? you put it in and measure what is left and you know the difference in weight is what went it?(!)

4. can you help me please on this chart. someone mentioned something about measuring the amount of air in the system or something and i didn't catch this. it shows degree F, psig (which is some kind of pressure value? how do i measure rhis in the truck? with the manifold? from where? then i go to the chart and look up ambient temp? then i see what it /should be in psig? and the difference between what it is and what it should be is the over pressurized or under pressurized?

5. where do i find what the pressure in the line (or lines?) should be please? or did i already list list above?(!)

THANK YOU

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From the pressure readings, it could be overcharged (anyone work on the system recently?) or another possibility is the fan clutch isn't doing it's job.
It's normal for the drier to be hot.
I'm not sure what replacing the expansion valve & drier will accomplish. Usually if the expansion valve is bad it either sticks open and the system pressures are close to the same or it sticks closed and the low side pressure goes to zero or into vacuum.
In any case, if you end up opening the system, I'd replace all the o-rings and schrader valves.
again big thanks as i try to put it together.
your point about the expansion valve was that if it was stuck open there would be nothing to keep the pressures different between the "low side" and the "high side"?
also your point about the TXV sticking closed was that the compressor will be sucking fluid from the low pressure line and when i plug in the manifold it will read zero or negative?
also FSM mentions a leak detector. are these worth it?
THANKS

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flintknapper

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1. sticker says range for "pressure in the system" (?)is 1.98 - 1.76 lbs? this is a weight? a force? do you measure this with the two dial manifold gauge? where are you measuring?
No...the sticker gives a range for the physical weight of refrigerant to be used. As weighed on a scale.
2. both the sticker and FSM say ND-oil 8 and FSM says 40cc/1.4 fl oz. this gets added if you remove the dryer or something? where does it get added?
IF you remove and replace an item (compressor, drier, condenser, evaporator) each of these parts require a specified amount of oil. You can add it directly into the part before installation or add it to system (replacing the amount lost) via the charging hoses. Also there is a maximum amount (in aggregate) for the entire system.
3. FSM says refrigerant in the system (after a vacuum i guess) is 850g +\- 50g (29.98 oz +\- 1.76 oz)? where does this get added? also how do you know how much weight you have added if you have full cans of it? you put it in and measure what is left and you know the difference in weight is what went it?(!)
FSM is referring to an evacuated system (empty). And is simply saying (in ounces) that you need to introduce that amount (weight) of refrigerant into the system. It will be added through the hose(s) of the manifold gauge set. IF you want to be accurate....you will weigh each can and mark it. Then subtract the difference in weight after each can is empty to arrive at how much liquid refrigerant you've put in the system. That is the 'correct' way to do it. But most folks will simply start charging the system and watch the gauges (for high and low pressure readings) while also monitoring the vent temps. There is an acceptable 'range' of pressure that varies with the ambient temperature. So staying within this 'window' and watching for diminishing returns in vent temps is good enough. You can 'fine tune' the charge to chase down those last couple of degrees of cooling....but most folks do not and shops NEVER do.
4. can you help me please on this chart. someone mentioned something about measuring the amount of air in the system or something and i didn't catch this. it shows degree F, psig (which is some kind of pressure value? how do i measure rhis in the truck? with the manifold? from where? then i go to the chart and look up ambient temp? then i see what it /should be in psig? and the difference between what it is and what it should be is the over pressurized or under pressurized?
I would dispense with that chart for your purposes. It shows the relationship of the pressure/temp when taking 'Static Pressure' and static pressure readings are only useful for a few things.....none of which we need to know in your case.
5. where do i find what the pressure in the line (or lines?) should be please? or did i already list list above?(!)
The pressure temperature relationship varies with the ambient temperature. We would need to know what the outside/ambient temp was at the time the charging was being done to give you the approximate high and low side pressures to look for.

There are charts for that (R134a) but not many of them agree.



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You didn't ask this but here goes: did you know that butane is a refrigerant, a flammable one but one that is interesting because you see the effects of ambient temperature on its boiling point. Take a butane lighter and hold it in your hand, get it nice and warm and it will light every time. take the same lighter and put it in the fridge for an hour, take it out and try to get it going... you can't, not till the heat from your hand warms the butane up enough to boil it and create gas and enough vapor pressure to drive up to the flame holder. Ever notice how a propane torch gets cold the longer you run it, and the flame gets smaller? That's because the vapor pressure in the canister of propane is getting lower with the temperature of the remaining liquid. Propane is also a refrigerant, a really good one actually. When the liquid refrigerant gets cold its boiling point goes down as does its vapor pressure. This is what the black and white temp chart is showing you for 134a. I used butane as an example because a lighter is something anybody can purchase, experiment with and see the direct results of vapor pressure.

On to what you did ask:

You can't do AC work without gauges, a vacuum pump and a decent kitchen thermometer (goes in a vent in the car to measure temp delta between ambient and refrigerated air).
I have a set up from harbor freight, yeah, yeah, yeah, get over yourselves; for the DIY'er they work fine. Get the good pump, not the cheap one, it pulls down to 3 microns vacuum.

Answers to your questions:
1) 0.90Kg max is the physical weight of the liquid refrigerant put into an evacuated system. If you look at the side of a can of 134 it will tell you how much is in the can. For example the black and white cans in your pic show 12 oz (340 grams) you need 900 grams, the cans are 340 so 900 /340 = 2.64 cans for a max fill. I'll let you do the math for the min fill.
Always add refrigerant through the low side, The first two cans can be run in, but you have to weigh the third can on a fish scale, with the hose attached, to ensure you don't overfill the system. Sometimes the system will be perfectly happy at the min fill value, still have to weigh the correct amount of refrigerant. Getting the second can in, and the partial third, can be a long process. As the refrigerant boils off in the can and becomes a gas, it cools the remainder in the can, the colder the can gets the lower the pressure in the can. (see the black and white temp chart you show) When the temp of the refrigerant in the can, and its subsequent pressure, is lower then the pressure in the system, it stops feeding gas into the system, and you can wait for the can to slowly...oh so slowly... feed gas into the system or you can force the process by raising the boiling temp of the refrigerant in the can by dunking it in a pan of warm water.

2) you add the new oil into the new dryer before you attach it to the system. It will distribute itself around when the system is running.

3) Answered with 1
4) The temp chart you show is the pressure 134A is at in a still (not moving) system at the temp shown. If you hook up the gauges to the high and low side and the system hasn't run for a good while the pressure across the gauges will be equal. At 75F the pressure =78.7psi. Near on useless information except to tell you there is indeed refrigerant in the system.

The meaning-full chart will compare the low and high side readings at the ambient temp.
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5) mostly answered with 1, as for measuring air or moisture in the lines, you can't. That's beyond the DIY'er. If that's the concern, take it someplace, and have the refrigerant recovered (not for you to reuse, just so its not released to atmosphere). Then change the dryer, draw a vacuum for an hour or so and fill per recommendation.

I suggest you go to the Sanden web site and poke around their technical data.
This is their quick trouble shooting chart.
and their trouble shooting guide.

Here is some of their tech bulletins. Even if you don't fully understand them, read through a couple, it will boost your general understanding of AC systems.
 
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Well, Flintnapper if nothing else.. the horse is well beaten. LOL
 

Irish Reiver

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Slight deviation from the OPs post but is there any way of knowing how much oil is in the system. My question is based on a fellow mudder who bought a 80 with crap AC. PO said he changed a bunch of bits but no receipts etc to show it was done by professionals.
Is there an acceptable way to flush a system of all the oil so the correct quantity of oil could be added?
 

flintknapper

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Slight deviation from the OPs post but is there any way of knowing how much oil is in the system.
Nope.

And that is part of the problem when a system has been 'serviced' several times but a complete evacuation and flushing has not been done.

It is common place for techs/DIYers to add refrigerant that has a couple of ounces of oil in it when they top off a unit or replace a single part. The 'rationale' being that some oil must have escaped with the refrigerant (in the case of a leak). Which is true....but we don't know how much.

So in goes the oil (just for good measure). Now an ounce or so too much oil won't hurt cooling performance appreciably.....but 3-4 ounces darn sure will. Too little oil and you'll have premature wear on the compressor. Too much and cooling suffers.
My question is based on a fellow mudder who bought a 80 with crap AC. PO said he changed a bunch of bits but no receipts etc to show it was done by professionals.
Is there an acceptable way to flush a system of all the oil so the correct quantity of oil could be added?

Yes, there is an acceptable way to flush oil from a system BUT it depends on the construction.

Lines of course are no problem. The Drier will simply be replaced so not an issue.

The evaporator can be flushed (if you know what you are doing) but doesn't hold much oil anyway.


The condenser is a 'maybe'. If it is parallel flow....then no. If it is serpentine tube and fin, yes, if it serpentine early model multi-tube....probably, if it is later model serpentine multi-tube (with really small openings) then it will not flush very well.

Compressors NEVER get flushed. TXV's unless just recently replaced should not be flushed, just replace it.

In this day and age.....market competition has driven prices of Condensers and Evaporators down (if you aren't an OEM purist). So replacing those items is often the better solution.
 

flintknapper

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again big thanks as i try to put it together.
your point about the expansion valve was that if it was stuck open there would be nothing to keep the pressures different between the "low side" and the "high side"?
also your point about the TXV sticking closed was that the compressor will be sucking fluid from the low pressure line and when i plug in the manifold it will read zero or negative?
also FSM mentions a leak detector. are these worth it?
THANKS

View attachment 2973759

^^^^^

I would like for you to take a sheet of paper and place it over the lower half of the diagram and NOTES written there....and never look at it again. As most of it is wrong. In fact, anyone reading this.....please disregard the notes.

I am going to explain in a simple way how A/C systems work (in general) and it is true of ALL auto A/C systems.

Let us begin by recognizing what your A/C system does. It cools the cabin and at the same time removes humidity.

How does it accomplish this? An A/C doesn't bring in cool air. It removes hot air via multiple exchanges of heat. The absence of heat/hot is what we think of as being cool.

Let' start at the COMPRESSOR. Its job is two fold. It 'pumps' the refrigerant though the system and 'compresses' the gases that enter it (hence its name). A compressor should NEVER have a liquid go through it (liquids are not compressible).

From the compressor the hot compressed gas enters the CONDENSER. Air flowing across/through the condenser cools the hot gas and it 'condenses' to liquid form. At the same time it releases the heat that was absorbed from the cabin and created when the gases were compressed. It 'sheds' the heat if you will.

From the condenser the high pressure liquid refrigerant enters the DRIER. Here the desiccant in the drier is supposed to capture any moisture that may be present in the refrigerant. We do NOT want moisture in the system at all for a variety of reasons. The high pressure liquid refrigerant then leaves the Drier flows though the hard lines to the EVAPORATOR but first must go through the TXV (Thermal Expansion Valve).

It enters the TXV who's job is to regulate the amount (trying to keep it constant). Your TXV is the BOSS of the system and basically has the final say. IF all is working well the high pressure liquid (with a little gas) is regulated to a lower pressure as it enters the evaporator.

The liquid here is quickly becoming cooler as it enters the evaporator. It will turn into a gaseous state as the cabin temperature tries to heat it and it 'boils'. This is where the 'magic' happens. The gas in the evaporator absorbs the heat from the cabin and takes it along to the compressor where the process starts all over again.

So these heat exchanges remove heat and moisture from the cabin. It takes several cycles (air/heat) for the air to start feeling cooler and the cabin to actually cool down. The moisture in the air/cabin condenses on the fins of the evaporator and is drained away and out of the vehicle. That is the puddle of water under your vehicle that you see when it is stationary.

So to recap....the Evaporator ABSORBS heat (collects it) and the condenser DISSIPATES heat (sheds it). The evaporator after a few cycles physically becomes cold itself....so the combination of removing heat and the blower fan moving air across the now cool surface of the evaporator is what gives us cool air at the vents.

The main point to remember is that the system REMOVES heat. When you fill your system with refrigerant ...you are not 'pouring in the cool' to be circulated. You are creating a 'system' that absorbs and transfers heat to the outside.
 
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flintknapper

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again big thanks as i try to put it together.
your point about the expansion valve was that if it was stuck open there would be nothing to keep the pressures different between the "low side" and the "high side"?
also your point about the TXV sticking closed was that the compressor will be sucking fluid from the low pressure line and when i plug in the manifold it will read zero or negative?
also FSM mentions a leak detector. are these worth it?
THANKS

View attachment 2973759


A few corrections for sake of accuracy. Not mean't to condemn, just need everyone to be on the same page.

Correction.jpg
 

jellis

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@SNLC where do you get automotive HVAC soft foam?!? He brings up a good point, there's a lot of foam used in the HVAC system and it will all be either dust or rock hard depending on construction (some is super soft like the stuff in the dampers he showed which turns to dust, other is more like neoprene and gets rock hard and brittle and breaks to pieces the second you move it). Replacing this stuff is one reason to do this yourself as shops are less likely to spend the time to do this right.

I have a large selection of this stuff on hand which I found very useful when rebuilding my AC system, -58 to 300 temp range. I would recommend primarily a variety of thicknesses, generally the wider the better because you can cut to size and some components require a 2" wide strip.

I hate AC work, but shops know its black magic and make up crap. I tried to take it in but I had the shop tell me my ENTIRE system needed replaced for a few grand after the vacuum pump sucked out a bunch of black gunk. This isn't even a thing, vacuum pump sucking out black gunk--totally made up. The system was fine it just needed a refrigerant that could dissolve both mineral oil (R12-based) and PAG (R134a-based) due to PO screwups, and that refrigerant is R12a. Or a flush. A hose sprang a leak so this time I flushed the system (loved this kit and used this flush) because I could tell there were slugs of different oils moving around in the sightglass, now hopefully I don't have to touch it for a while because the AC system has by far been the most perplexing.
 
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where do you get automotive HVAC soft foam?!?

I'm wondering that, too.

For my lower damper door, I used thin EVA foam. It's sold under the Yaya Han brand at Joann's Fabric, Michael's, Hobby Lobby, etc. EVA foam can withstand up to something like 90 - 120°C. I also cut narrow strips to replace foam that seals the case around the blower.

With regards to temperature, I don't think it matters for anything you'll touch during an AC overhaul. Air goes from the blower on the far right, through the AC evaporator core, then it goes on to pass through the heater core near the center of the dash. I don't think that anything to the right of the heater core is going to see extreme temperatures.
 

TomH

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Excellent info here from the AC experts. I've been working on the AC in my Tacoma trying to find the leak. Looks like it's going to be best to just break the bank and get a new condenser and evaporator.

I found these instructions helpful for testing the system for leaks and refilling.
 

ToyotaDon

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I would dispense with that chart for your purposes. It shows the relationship of the pressure/temp when taking 'Static Pressure' and static pressure readings are only useful for a few things.....none of which we need to know in your case.

4) The temp chart you show is the pressure 134A is at in a still (not moving) system at the temp shown. If you hook up the gauges to the high and low side and the system hasn't run for a good while the pressure across the gauges will be equal. At 75F the pressure =78.7psi. Near on useless information except to tell you there is indeed refrigerant in the system.

You guys are sharing great information but I will repeat again that the chart is useful in confirming there is air in the system. Air is a noncondensable gas and will raise the pressure of the refrigerant for the given temperature. If the static pressures are higher than what the chart shows, the system is contaminated.

It enters the TXV who's job is to regulate the amount (trying to keep it constant). Your TXV is the BOSS of the system and basically has the final say. IF all is working well the high pressure liquid (with a little gas) is regulated to a lower pressure as it enters the evaporator.

The liquid here is quickly becoming cooler as it enters the evaporator. It will turn into a gaseous state as the cabin temperature tries to heat it and it 'boils'. This is where the 'magic' happens. The gas in the evaporator absorbs the heat from the cabin and takes it along to the compressor where the process starts all over again.

To clarify, the X part of the TXV stands for "expansion" which means this is where the magic of "cooling" happens. The coldest point of the system should be directly after the TXV and from there, its temperature will increase with the heat added in the evaporator.

Not necessarily relevant to help the OP, but clarifying nonetheless.
 

flintknapper

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You guys are sharing great information but I will repeat again that the chart is useful in confirming there is air in the system. Air is a noncondensable gas and will raise the pressure of the refrigerant for the given temperature. If the static pressures are higher than what the chart shows, the system is contaminated.
Correct. Static pressures have a use. Contamination is one (though you'd have no idea how bad). Static pressure will also reveal if there is enough liquid refrigerant in the system to satisfy the minimum pressure required by the binary switch to allow the compressor to engage. But again...not how much refrigerant. 2 ozs or 20 ozs will show the same pressure. Poor installation practices (not purging your manifold lines) will introduce some amount of air into the system and I can guarantee you....most shops and many DIYers do this. We may be almost certain there is some amount of contamination in systems poorly serviced. So I am not arguing your point, just saying the OP was looking at static pressures thinking they related to operating pressures and informing him that static pressures (in his case) tell us little.
To clarify, the X part of the TXV stands for "expansion" which means this is where the magic of "cooling" happens. The coldest point of the system should be directly after the TXV and from there, its temperature will increase with the heat added in the evaporator.
Yes, this is the coldest portion of the system (ideally about 32° F) and exactly the reason we don't want moisture in the system ( that can freeze and block your TXV) or cause the outer portion of the evaporator to freeze up.

Just trying to keep things in layman's terms and simple. We could make a day of discussing Subcooling, Superheat, the Latent heat of vaporization, heat exchange properties, contaminants etc...

We purposely did not touch on the troubleshooting aspects (as they are many and varied) but just threw a little of what needs to be known out there. 👍
 
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Yeah, lets not overwhelm the OP.
he needs enough information to be safe and effective. He doesn't need to learn to be an AC tech.
But that is good info about the temp and static pressure not matching up, a good place to start when he gets his gauges.
 
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hi gents.

TONS of thanks for this help. i have to study the last couple of answers by rustymarlin and flintknapper. i also see these is more information here but i am still back always so some follow up questions please on just the point i have gotten to so i can catch up:

1. what is "nylog on the o rings" and what does it do? or is this some kind of nylon spray or something?
2. for schraeder valves am i picking up OEM valves from toyota or can i pick these up at a good AC austin supply store? also does the rubber wear out or it is the core leaks or what?
3. any value in buying a leak detector? FSM seems to mention it a bunch of times.
4. any specific widths on the heat resistant automotive foam?

process questions/comments:
A. i don't think i understood the fact that you are measuring weights when you put it in. then you are measuring pressures once you have it in and charged it i guess? then you are sort of going back and forth between pressures and actual vent temps - and as compared to what you should be getting at that ambient temperature from the chart (or something) i suppose this makes sense though?
B. they seem to mix and match between ounces of weight and pounds and then they give an over under value. this is sort of confusing so i ran the numbers (image attached) for amount of refrigerant i think it is
max: 31.74 oz =1.984 lbs
min: 28.22 oz = 1.764 lbs
C. someone kindly mentioned 12 oz = 340g. can anyone remind me where ounces to grams is important?
D. you weight the third can on a fish scale (or digital scale or even balance beam i guess) while it is hooked up to the manifold so you know what is going in? and somehow you try to include a constant weight of the hose when you start measuring i guess? then this allows you to know you are putting in between max and min weights of freon?

ALSO. someone please back check me here:

given where i am at i could get all my parts together, go to a shop and pay to vacuum the freon, put in new o rings, new TXV, new dryer (with oil in it), clean the evaporator, clean or replace the condensor, refurbish the water pump at a good shop? then do something with shraeder valves and something specific with o rings?

i should also fully flush the evaporator and condensor i guess?

anything else?

i have some catching up to do here and i am sure i am still tripping on my shoelaces here and there but a TON of thanks. it's starting to setup shifting around and ordering into something somewhat understandable to me.

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Slight deviation from the OPs post but is there any way of knowing how much oil is in the system. My question is based on a fellow mudder who bought a 80 with crap AC. PO said he changed a bunch of bits but no receipts etc to show it was done by professionals.
Is there an acceptable way to flush a system of all the oil so the correct quantity of oil could be added?
deviations always welcome fwiw. if it's asking about facts jump in with two feet any time...
 
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hi gents.

TONS of thanks for this help. i have to study the last couple of answers by rustymarlin and flintknapper. i also see these is more information here but i am still back always so some follow up questions please on just the point i have gotten to so i can catch up:

1. what is "nylog on the o rings" and what does it do? or is this some kind of nylon spray or something?
Its a lubricant, comes in a little plastic bottle, spread it on the o-rings before installing them.
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2. for schraeder valves am i picking up OEM valves from toyota or can i pick these up at a good AC austin supply store? also does the rubber wear out or it is the core leaks or what?
I think I used after market. Put a little nylog on the seals before installing. There's a little brass tool you can buy for install.
3. any value in buying a leak detector? FSM seems to mention it a bunch of times.
They are touchy, and prone to false readings for newbies. I have one. Never used it on automotive stuff as they work best in still atmospheres, not out in the driveway. If you are changing everything and put the nylog on the o-rings, there shouldn't be any leaks.
4. any specific widths on the heat resistant automotive foam?
unkown
process questions/comments:
A. i don't think i understood the fact that you are measuring weights when you put it in. then you are measuring pressures once you have it in and charged it i guess? then you are sort of going back and forth between pressures and actual vent temps - and as compared to what you should be getting at that ambient temperature from the chart (or something) i suppose this makes sense though?
yes that's how it works.
B. they seem to mix and match between ounces of weight and pounds and then they give an over under value. this is sort of confusing so i ran the numbers (image attached) for amount of refrigerant i think it is
max: 31.74 oz =1.984 lbs
min: 28.22 oz = 1.764 lbs
C. someone kindly mentioned 12 oz = 340g. can anyone remind me where ounces to grams is important?
The sticker under the hood is in kg, the cans are marked in grams and oz, there are 1000g/kg so I used the metric system to weigh in the charge in grams, why convert units when you don't have to, less chance of error.
D. you weight the third can on a fish scale (or digital scale or even balance beam i guess) while it is hooked up to the manifold so you know what is going in? and somehow you try to include a constant weight of the hose when you start measuring i guess? then this allows you to know you are putting in between max and min weights of freon?
Yes, attach the third can to the input line of the gage set. Then hang the assembled can and hose off the spring scale, I hung the spring scale off a piece of mechanics wire wrapped around the hood latch loop. Then weigh in the last portion of the charge, stop short by a few grams, let the system stabilize and check your vent temps and gage pressures against ambient temp. If everything is still low, add a few more grams. Watch the temps and gages, wash rinse and repeat as needed. It is not a fast processes nor one that can be hurried.
ALSO. someone please back check me here:

given where i am at i could get all my parts together, go to a shop and pay to vacuum the freon, put in new o rings, new TXV, new dryer (with oil in it), clean the evaporator, clean or replace the condensor, refurbish the water pump at a good shop? then do something with shraeder valves and something specific with o rings?
If you are going to do it yourself, the absolute last step is unpackaging the drier, adding oil and attaching, this should be done quickly to limit moisture being absorbed by the desiccant inside.

Water pumps are generally just replaced vs refurbished. Its also not part of the AC system (directly) so I'm a bit confused why its brought into the thread.
Order of OPs for me:
Remove all old freon (hired this out).
Stripped system. I had no idea what was bad or good, only knew that it didn't work and all parts looked original.
Changed stuff I probably didn't need to, but it was worth it to me to know I started fresh.
Compressor, high and low pressure hoses, TXV, Evaporator and dryer.
The condenser looked fine, no bent fins or anything.
Flushed the remaining hard lines as my dryer had exploded internally and there w ere desiccant balls spread from the dryer to the TXV.
Replaced all the old bits with new bits. Rubbed Nylog on all the new o-rings as parts were reassembled, took apart the condenser fittings and added new o-rings.
Rebuilt the evaporator box with new foam seals. Didn't know there was a difference in foams till this thread; it's been working for two years now, guess we'll see how much longer it goes with the Lowes window seal foam...:meh:

Installed new dryer, stripped fitting mounting bolt, because I miss read the torque spec. Ordered new drier.
Installed new, new dryer.
Drew vacuum for an hour and sealed system, watching gages for leak down.
Added refrigerant per instructions and have enjoyed AC so cold it'll make your nipps stand at attention for the last two summers.


i should also fully flush the evaporator and condensor i guess?

might as well, can't hurt anything.
anything else?
If you find desiccant balls (it will be obvious) in the TXV when you take it out, you'll need to flush the line between the dryer and the TXV or you will just be taking the system apart and replacing the TXV again.
i have some catching up to do here and i am sure i am still tripping on my shoelaces here and there but a TON of thanks. it's starting to setup shifting around and ordering into something somewhat understandable to me.
You'll figure it out. Its not rocket surgery.

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