A/C help please!

[Low Elco]

I know NOTHING about AC stuff. AT ALL. Got an 87 SWB C-10 with factory ac that I got with none of the engine related A/c stuff. I've bought a receiver, orifice tube, compressor, compressor hoses. I yarded all the compressor brackets. Turned out the condensor was broken, so I got one of those. It's a completely different design optimized for 134, and had some fitment issues, which are apparently a common complaint. I got that in, got the brackets on the compressor, and saw a sticker that says the compressor is pre oiled and that I need to put "x" ounces of oil in. What oil? You're supposed to scan the QR code on the sticker to find out, but that just takes you to a chart of all makes and models where I think they're saying they put mineral oil in. Now, If I'm right, you can't have mineral oil in a 134 system, and you can't get 12. So now what do I do? Also I just saw a video where I guess there's a high side switch in the compressor? I don't have that or any wiring for it. Where does the orifice tube go? Anyway, If anyone can help, let me know. I've been wrenching for a long time, but I know nothing about this.

Thanks, Chip

[Ski-me]

I installed all the new parts in my 89' and then brought it to a dealer to add the oil, evacuate the system and then charge it up. I think they pull a vacuum first to be sure it can hold (tests my work), and then filled as needed with R134.

I think the orifice goes into the bottom section of the radiator thing at the firewall.

[Valarius_Starchaser]

Mineral Oil is for an R12 system it can still be found but is not cheap the system is often tested with Hydrogen I believe to ensure you don't lose the R12

As far as adding X oil to the system you would take the old compressor and dump the old oil into a container marked for ozs to make sure you add the correct amount of oil back to the system over and under oiling a system are just as bad

PAG oil is what you would need to add to a R134a system

What is the compressor model number?

[foamypirate]

Originally Posted by Low Elco

I know NOTHING about AC stuff. AT ALL. Got an 87 SWB C-10 with factory ac that I got with none of the engine related A/c stuff. I've bought a receiver, orifice tube, compressor, compressor hoses. I yarded all the compressor brackets. Turned out the condensor was broken, so I got one of those. It's a completely different design optimized for 134, and had some fitment issues, which are apparently a common complaint. I got that in, got the brackets on the compressor, and saw a sticker that says the compressor is pre oiled and that I need to put "x" ounces of oil in. What oil? You're supposed to scan the QR code on the sticker to find out, but that just takes you to a chart of all makes and models where I think they're saying they put mineral oil in. Now, If I'm right, you can't have mineral oil in a 134 system, and you can't get 12. So now what do I do? Also I just saw a video where I guess there's a high side switch in the compressor? I don't have that or any wiring for it. Where does the orifice tube go? Anyway, If anyone can help, let me know. I've been wrenching for a long time, but I know nothing about this.

Thanks, Chip

Since you are starting with a basically a brand new system, you can start with factory specs for oil. My 87' manual specs 10oz of oil for the system.

Since you are converting to R134a (I presume...), ditch the oil in the new compressor. This way you aren't guessing at the amount of oil in the system (who knows how much oil Bob put into the compressor during manufacturing...) Turn it over, and drain out as much as possible. Be sure to turn over the compressor while doing so (make sure you actually turn the shaft, not just the clutch).

Go ahead and flush the evaporator with some A/C flush solvent or non-chlorinated brake clean, and make sure you get it completely dry.

Add the oil back to the system. The R4 should use PAG100 at a minimum, but PAG150 is even better. I like oil with UV dye in it, for future leak detection. Put a couple of ounces everywhere. I like 3-4oz in the accumulator (which is different from a receiver/drier. Squarebodies all had accumulators; there is a difference). 1-2oz in the suction hose (big hose). 2-3oz in the compressor, spin the shaft around a few times (15 in each direction would be good). 1-2oz in the condenser inlet. Just make sure you get the 10oz into the system.

The accumulator should be the last thing installed, since it contains a dessicant. If you open it up, it will start absorbing moisture.

The orifice tube goes into the small tube on the bottom of the evaporator, SHORT SIDE TOWARDS EVAPORATOR. The long side should be facing towards the small liquid line coming from the condenser. It should go all the way into the tube to where you can just barely see the tab, slightly recessed into the tube.

I would recommend new hoses, if possible. Any good A/C shop should be able to braze a fitting into the hard line on the high side for a high pressure cut off switch (HPCO). The compressor discharge line, before the condenser, is optimal placement, since the system will shutdown if the condenser gets blocked up. If you put it after the condenser, and the condenser plugs up, creating high pressure at the compressor, the HPCO would not trip, since it's upstream of the blockage. The HPCO should be wired in series with the low pressure switch.

Use refrigerant oil or Nylog (Nylog is polymerized refrigerant oil) to coat all your o-rings and threads. This helps prevent damage to the o-rings during tightening and helps get a good seal.

Once everything is all buttoned up and put together, you can have the system vacuumed to boil off any remaining moisture and verify the system holds a vacuum (indicating no leaks). It can then be charged. A lot of places prefer to start at 80% of the R12 charge, but I prefer to start lower, having experienced a shop overcharging my conversion right off the bat with the 80% number.

Hope that gives you a good start. Let me know if you have any more questions. I just recently went through all of this myself. Once I got my refrigerant charge correct (the shop I originally went to overcharged it), I'm getting pretty decent performance for an old system with the evap in the engine bay. I've seen down to 42* at the vent outlet in 95F heat. Full blast in 100F - 70% humidity was hitting 48*.

[SCOTI]

I'm sorting through this as well w/my 89 dually. I'm currently on my 2nd charge but the pressures looked weird. Best so far is 60°F @ the vent on max.

My orifice tube went on the discharge line from the condenser to the evap @ the bottom of the evap on the firewall.
The compressor cycle swtch on mine is @ the accumulator.
Mine has an r4 (Pancake) compressor (as does my 90 swb/new body style). The high-side switch was @ the back of the compressor (from what I remember).

[Low Elco]

Originally Posted by foamypirate

Since you are starting with a basically a brand new system, you can start with factory specs for oil. My 87' manual specs 10oz of oil for the system.

Since you are converting to R134a (I presume...), ditch the oil in the new compressor. This way you aren't guessing at the amount of oil in the system (who knows how much oil Bob put into the compressor during manufacturing...) Turn it over, and drain out as much as possible. Be sure to turn over the compressor while doing so (make sure you actually turn the shaft, not just the clutch).

Go ahead and flush the evaporator with some A/C flush solvent or non-chlorinated brake clean, and make sure you get it completely dry.

Add the oil back to the system. The R4 should use PAG100 at a minimum, but PAG150 is even better. I like oil with UV dye in it, for future leak detection. Put a couple of ounces everywhere. I like 3-4oz in the accumulator (which is different from a receiver/drier. Squarebodies all had accumulators; there is a difference). 1-2oz in the suction hose (big hose). 2-3oz in the compressor, spin the shaft around a few times (15 in each direction would be good). 1-2oz in the condenser inlet. Just make sure you get the 10oz into the system.

The accumulator should be the last thing installed, since it contains a dessicant. If you open it up, it will start absorbing moisture.

The orifice tube goes into the small tube on the bottom of the evaporator, SHORT SIDE TOWARDS EVAPORATOR. The long side should be facing towards the small liquid line coming from the condenser. It should go all the way into the tube to where you can just barely see the tab, slightly recessed into the tube.

I would recommend new hoses, if possible. Any good A/C shop should be able to braze a fitting into the hard line on the high side for a high pressure cut off switch (HPCO). The compressor discharge line, before the condenser, is optimal placement, since the system will shutdown if the condenser gets blocked up. If you put it after the condenser, and the condenser plugs up, creating high pressure at the compressor, the HPCO would not trip, since it's upstream of the blockage. The HPCO should be wired in series with the low pressure switch.

Use refrigerant oil or Nylog (Nylog is polymerized refrigerant oil) to coat all your o-rings and threads. This helps prevent damage to the o-rings during tightening and helps get a good seal.

Once everything is all buttoned up and put together, you can have the system vacuumed to boil off any remaining moisture and verify the system holds a vacuum (indicating no leaks). It can then be charged. A lot of places prefer to start at 80% of the R12 charge, but I prefer to start lower, having experienced a shop overcharging my conversion right off the bat with the 80% number.

Hope that gives you a good start. Let me know if you have any more questions. I just recently went through all of this myself. Once I got my refrigerant charge correct (the shop I originally went to overcharged it), I'm getting pretty decent performance for an old system with the evap in the engine bay. I've seen down to 42* at the vent outlet in 95F heat. Full blast in 100F - 70% humidity was hitting 48*.

Thanks for the easy and slow version. This helps a lot.

[hatzie]

Originally Posted by Low Elco

I know NOTHING about AC stuff. AT ALL. Got an 87 SWB C-10 with factory ac that I got with none of the engine related A/c stuff.
I've bought a receiver, orifice tube, compressor, compressor hoses. I yarded all the compressor brackets. Turned out the condenser was broken, so I got one of those. It's a completely different design optimized for 134, and had some fitment issues, which are apparently a common complaint. I got that in,

You don't absolutely need a parallel condenser but it helps vent temps with lower output compressors like the Harrison R4 GM used on the 80's vehicles. Since you were replacing it anyway no reason to use the old style condenser.

Again since it's apart already... I would recommend a Sanden type compressor or one of the huge old 1970's Harrison A6 compressors rather than the Radial R4. The R4 has a terrible reputation for long term reliability and it doesn't move near as much refrigerant as the A6 or the new Sanden type.

Originally Posted by Low Elco

got the brackets on the compressor, and saw a sticker that says the compressor is pre oiled and that I need to put "x" ounces of oil in. What oil? You're supposed to scan the QR code on the sticker to find out, but that just takes you to a chart of all makes and models where I think they're saying they put mineral oil in. Now, If I'm right, you can't have mineral oil in a 134 system, and you can't get 12. So now what do I do?

Don't jump ahead.

The first step is flushing out the evaporator and any used hard-lines with a good refrigeration system flush chemical to get rid of any leftover mineral oil and crud. Road grit and bugs and old refrigerant oil tend to make a nasty hard to remove varnish that can flake off and plug stuff up. If the evaporator inlet and outlet has been open to the atmosphere you may want to replace it depending on the level of contamination with road grit and bugs. You can probably run a nylon or copper brush through the hard-lines but not the evaporator. Your goal should be to have as close to ZERO leftover refrigerant oil in the system as you can manage. Any extra oil will raise your vent temps because it insulates the inside of the condenser and evaporator.

If the hard-lines have a muffler you should get that removed and replaced by a section of brazed in hard-line because they are impossible to completely flush out.

Make sure all your soft lines and seals are R134a compatible. You can replace the old R12 hose with R134a barrier hose without buying new hard lines. Cut the ferrules off and install new ferrules and fresh barrier hose just like building up hydraulic hoses for a loader, plough, or baler.

I use Ester refrigerant oil with UV leak detection dye already added from an un-opened can. I prefer Ester oil over PAG oil for these reasons: better refrigerant compatibility, does not eat seals, does not absorb moisture and is non electrically conductive. The last one is only important for electric compressors, such as the ones on hybrids and appliances. The downside is it does not lubricate quite as well as PAG oil under ideal conditions but retrofits are really really really not ideal conditions and PAG really doesn't get along well with mineral oil.

Filling the compressor with oil and installing the accumulator/dryer is the last step before you sweep the system with inert gas and pull a hard vacuum.

There's a Whole-System and Compressor oil charge. The Whole system oil charge includes the compressor charge. PAG and Mineral refrigerant oils are hygroscopic, just like glycol brake fluid, they will pull moisture from the air. I usually drain the compressor overnight and measure the volume I drain out. I fill with fresh Ester oil from a sealed can while I'm closing the system.

I use one of my MIG or better yet completely inert gas TIG tanks. Argon, Helium, Argon/Helium mix, CO2, 75:25(Argon/CO2), or welding Tri-Mix (CO2/Argon/Helium) welding gas. I prefer the truly inert Noble gases Ar & He to sweep systems because they are really non reactive.

The full system oil charge is in the service manual. Subtract the amount of oil in the compressor from the Whole-System charge amount in the service manual... this is the amount you will need to put in your refrigerant oil injector to finish the oil charge after you begin filling with refrigerant. I usually complete the oil charge just after the LPCO allows the compressor to cycle on...

Originally Posted by Low Elco

Also I just saw a video where I guess there's a high side switch in the compressor? I don't have that or any wiring for it. Where does the orifice tube go? Anyway, If anyone can help, let me know. I've been wrenching for a long time, but I know nothing about this.

The 1987 system only has a LPCO on or very near the accumulator/dryer. The HPCO, if one exists, is on the compressor head or installed in a bung in the high side line near the compressor line fitting. It can be wired in series between the LPCO and the electromagnet in the Clutch or even in the clutch ground. It cuts compressor power when the pressure gets too high. People tend to overcharge when retrofitting refrigerants driving the compressor head pressures through the roof. High outdoor ambient temps 105°F plus can drive the head pressure pretty high with R134a on a reasonable charge too. That's why the HPCO is recommended. Don't just whack it with x lbs of R134a because the service manual called for x lbs of R12. You will not need as many lbs of R134a refrigerant as R12.

[Low Elco]

Originally Posted by hatzie

You don't absolutely need a parallel condenser but it helps vent temps with lower output compressors like the Harrison R4 GM used on the 80's vehicles. Since you were replacing it anyway no reason to use the old style condenser.

Again since it's apart already... I would recommend a Sanden type compressor or one of the huge old 1970's Harrison A6 compressors rather than the Radial R4. The R4 has a terrible reputation for long term reliability and it doesn't move near as much refrigerant as the A6 or the new Sanden type.



Don't jump ahead.

The first step is flushing out the evaporator and any used hard-lines with a good refrigeration system flush chemical to get rid of any leftover mineral oil and crud. Road grit and bugs and old refrigerant oil tend to make a nasty hard to remove varnish that can flake off and plug stuff up. If the evaporator inlet and outlet has been open to the atmosphere you may want to replace it depending on the level of contamination with road grit and bugs. You can probably run a nylon or copper brush through the hard-lines but not the evaporator. Your goal should be to have as close to ZERO leftover refrigerant oil in the system as you can manage. Any extra oil will raise your vent temps because it insulates the inside of the condenser and evaporator.

If the hard-lines have a muffler you should get that removed and replaced by a section of brazed in hard-line because they are impossible to completely flush out.

Make sure all your soft lines and seals are R134a compatible. You can replace the old R12 hose with R134a barrier hose without buying new hard lines. Cut the ferrules off and install new ferrules and fresh barrier hose just like building up hydraulic hoses for a loader, plough, or baler.

I use Ester refrigerant oil with UV leak detection dye already added from an un-opened can. I prefer Ester oil over PAG oil for these reasons: better refrigerant compatibility, does not eat seals, does not absorb moisture and is non electrically conductive. The last one is only important for electric compressors, such as the ones on hybrids and appliances. The downside is it does not lubricate quite as well as PAG oil under ideal conditions but retrofits are really really really not ideal conditions and PAG really doesn't get along well with mineral oil.

Filling the compressor with oil and installing the accumulator/dryer is the last step before you sweep the system with inert gas and pull a hard vacuum.

There's a Whole-System and Compressor oil charge. The Whole system oil charge includes the compressor charge. PAG and Mineral refrigerant oils are hygroscopic, just like glycol brake fluid, they will pull moisture from the air. I usually drain the compressor overnight and measure the volume I drain out. I fill with fresh Ester oil from a sealed can while I'm closing the system.

I use one of my MIG or better yet completely inert gas TIG tanks. Argon, Helium, Argon/Helium mix, CO2, 75:25(Argon/CO2), or welding Tri-Mix (CO2/Argon/Helium) welding gas. I prefer the truly inert Noble gases Ar & He to sweep systems because they are really non reactive.

The full system oil charge is in the service manual. Subtract the amount of oil in the compressor from the Whole-System charge amount in the service manual... this is the amount you will need to put in your refrigerant oil injector to finish the oil charge after you begin filling with refrigerant. I usually complete the oil charge just after the LPCO allows the compressor to cycle on...



The 1987 system only has a LPCO on or very near the accumulator/dryer. The HPCO, if one exists, is on the compressor head or installed in a bung in the high side line near the compressor line fitting. It can be wired in series between the LPCO and the electromagnet in the Clutch or even in the clutch ground. It cuts compressor power when the pressure gets too high. People tend to overcharge when retrofitting refrigerants driving the compressor head pressures through the roof. High outdoor ambient temps 105°F plus can drive the head pressure pretty high with R134a on a reasonable charge too. That's why the HPCO is recommended. Don't just whack it with x lbs of R134a because the service manual called for x lbs of R12. You will not need as many lbs of R134a refrigerant as R12.

Thanks for the great reply. Not sure where to get some of the stuff you're spec'ing out, and never heard of filling the system with inert gas, or how to do it. Already have the stock parts in hand, moving forward. A lot of the stuff you're saying sounds good, but it adds complication to my already overloaded hard drive, and this is for someone else, with their money. I get a bit more experience, I may try shenanigans. I'm absolutely sure you're right, but some of that is above my pay grade.

[hatzie]

JungleEddy method for charging an AC system with a non original refrigerant without overcharging. This was posted in one of the Hydrocarbon refrigerant discussion threads on the old aircon boards that no longer exist. This works fairly well no matter what refrigerant you choose.

Unfortunately I don't have the posts Eddy has referenced on Vacuum, Flushing, Oil Supply, Leaks etc. They are not archived on the wayback machine.

You will need vent thermometers, AC gauges, and box fans.

--------------
Posted by JungleEddy on September 05, 2001 at 08:17:44: via: or 66.25.151.188

More important stuff.

How to charge an A/C system.

Note: This method will work for any automobile A/C system regardless of refrigerant type. The pressures I list here will only be correct for HC’s.

I have been trying for the past couple of weeks to come up with a “system” that would allow just about anyone to properly charge their A/C system. While this method I have developed is not fool-proof, it yields the closest thing to a perfect charge I have found. I have tested it on three “non A/C” mechanics in the past few days with great success.
First: If you have not read my previous post on vacuum, flushing, oil supply, leaks and fans etc etc, please do so now. You still need a properly assembled system to get proper cooling!

This ENTIRE process makes a few IMPORTANT assumptions!!
1. The ambient air is OVER about 84 degs.
2. You have a set of A/C gauges
3. You do not take shortcuts.
4. You are able to read and comprehend English.

This process will work down to about 80 degs ambient air, but will be MUCH MUCH easier to over charge below 85 degs ambient air!! Relative high side pressures will be lower at 80 degs ambient and pressure drop after wetting the condenser will be less dramatic.

Pull a hard vacuum for a minimum of 15 minutes, 60 minutes is perfect. Static charge the system to about 65 psi while the engine is NOT running.

If you have a low pressure cut out switch on your system you will need to adjust it down to 18-19 psi sometime during this process. Personally, I find it easiest to do this about midway (now) through the charging process. Remove the connector from the switch and turn the adjustor screw about 1 full turn counterclockwise from its factory position. (counterclockwise is less psi, clockwise is more psi, 99% of the time) Start the engine and turn on the A/C, recirc, max fan, and engine at idle. Max fan is important, since it will help keep the evaporator from freezing as you charge. Charge the system slowly (if you have to!) until the compressor stays on fairly continuously at IDLE. The adjustment I illustrated above should give you a cut out psi of 12-18 psi. Watch your low side gauge and SLOWLY increase engine rpm. The low side pressure will drop slowly but substantially because you are still undercharged. Watch it drop from 20+ psi down through the teens and carefully note where the compressor cuts out. Return the engine to idle and pull the connector to the cut out switch and adjust it accordingly. Try this several times until, as the engine is slowly revved the compressor cuts out at about 18-19 psi on the low side.

The Charge:
Bring the engine rpms up to a continuous 1200-1800 rpm. Begin to add refrigerant (if you have to) SLOWLY until you notice that the air at the vents is noticeably cooler than the ambient air, say at about 65-75 degs or so.
At this point grab your garden hose and hose down the condenser; soak it once only. Your pressures will drop dramatically. The high side should drop below 150 and the low side should drop low enough to cycle the compressor, or if the switch is temporarily “jumped” the low side should be well below 20 psi. I prefer at this stage to jump the connector to the pressure switch to keep the compressor running continuously. It makes the process go much faster, but you risk freezing the evaporator. Now, watch the system pressures rise as the water evaporates and the heat in the system and stabilizes and equalizes. This can take a long time if you have a mechanical radiator fan. The point where the pressures remain relatively constant is called equalization.

Here is the key:
(After wetting the condenser) As you are watching the high side pressure rise from 160psi through (potentially) about 205psi the LOW side should REMAIN from 21-24 psi. If the high side never sees 145+psi you are still low on charge as long as the ambient is 85 degs or above. If as the high side needle swings through 160psi the low side is still below 20psi, you will add more refrigerant AFTER wetting the condenser again and dropping the pressures. Keep doing this until the low side remains at 21-24 psi while the high side swings through 160psi and finally settles at equalization (no more rise) Keep the engine rpms constant and wait for equalization (or close) each time before wetting and charging. If you are going carefully and slowly you could see a high side over 225 at equalization BEFORE you reach a full charge. The high side will DROP as you come closer to a full charge. Be aware that if you over-charge, the high side will climb again and never come down.

Note: If the ambient air is above 95 degs, stop watching the low side after the high side climbs past 205 or so. Especially if you have weak fans.

Note: Take your time and wait for equalization and water evaporation off the condenser before adding refrigerant. An overcharge can occur with no more than an extra 1.5 ounces of refrigerant!!

You can double-check your work at any time (and I suggest doing so) by waiting for full equalization and stabilization of pressures. Then, carefully MIST water into the condenser SLOWLY SLOWLY dropping the system pressures and watching for the same readings on the gauges as listed above.

When finished you should have a sweaty return line all the way back to the compressor. When the return line begins to feel chilled over the first portion of its length, you are approaching full charge. Do not forget to reconnect the low pressure cut out switch!

Do not consider your vent temps accurate until the vehicle has been driven for about 10 minutes at moderate highway speeds!!!! Idle low side pressure should not exceed 40 psi (34-38 actual) if everything is working well; good fans etc….

The idea here is that the compressor should NOT cycle when ambient air temps are above 81-84 degs.

Interesting note for tech heads: If you are charging SLOWLY. You will find at first that the high side will be at a higher pressure, after equalization, on a low charge than at a correct charge! Remember, raised heat = expansion and/or pressure.
Why: (basically)
Within a certain range, the pressure in the condenser (high side) is MUCH more affected/determined by the temperature of the refrigerant than its volume.
ALL THINGS BEING EQUAL, the condenser has the ability to lower the temperature of the refrigerant passing through it “X” amount and no more. The compressor, in compressing the refrigerant, heats or raises the temperature of the refrigerant “Y” amount. Lets say the temperature of the refrigerant entering the compressor via the return line is “Z”. So the final temperature “T” of the refrigerant that gets to the orifice/exp valve is: Z+Y-X=T
If we could lower the value of “T” the entire system would work more thermally efficiently and at lower pressures on the high side. So, ALL THINGS BEING EQUAL, you could 1. get a larger condenser and raise your “X” value or 2. lower the value “Z”.
A full charge on an A/C system will not only have enough refrigerant in it to keep the evaporator “chilled”, but JUST ENOUGH that the line leaving the evaporator and returning to the compressor will also have substantially cooled refrigerant in it THUS LOWERING YOUR “Z” value!! Hello!!
Note: Over charging will allow actual condensed refrigerant (liquid) to make it all the way back to the compressor. As we all know, you cannot compress a liquid…boom/screech.
----------------

[Low Elco]

WOW! Thanks for all the info, guys. I'm just a bit nervous, 'cuz this is someone else's $, and I don't want to mess this up. And apparently there are 1.937 ways to do that. I got the liquid line out of a salvage yesterday, which should have me ready to go. Hopefully, the truck will be back on its wheels tonight and I can start trying to piece this thing together. I'll report back.

[hatzie]

Sweeping or purging is just a way to blow moisture laden air out of the just closed system and then pressure test using something other than $$$$ refrigerant.
You push a dry gas from the Low side charge valve to the high side valve for a minute or two. You then pressurize to around 20 or 30psi to test for leaks and make sure the LPCO and compressor actually work before taking it to someone with a vacuum pump. You can skip sweeping if you have your own vacuum pump but it's a nice easy test before spending an hour or more pulling a vacuum only to discover you have a leak.

Sweeping actually used to be done with refrigerant in the 1960's and 70's but that's now very illegal because it releases ozone depleting refrigerant into the atmosphere. You can get fined for sweeping with R290 (Propane) even though it's not an ozone depleting refrigerant.

[Low Elco]

Well, we tried to get it together over the weekend, and got a bad "new" compressor. The o-ring reliefs in the back of the compressor were machined too deep to seal. Tried to order another, waited 2 days, they ordered a hose. Grrrr.... took compressor back yesterday, sealed off hose ends, ordering another one, here Thursday. Gonna try this again. Went to HF and bought my own gages and vac pump. WE shall see.

[twinturboc10]

Did your new compressor have o-ring grooves, or was the seal area flat? Some of the newer compressors have gone from an o-ring to washers used with later OEM 134a designs. Some parts stores have a box of these misc washers and pilots. Something to look into if the new compressor is the same as the one you took back.

[Low Elco]

Originally Posted by twinturboc10

Did your new compressor have o-ring grooves, or was the seal area flat? Some of the newer compressors have gone from an o-ring to washers used with later OEM 134a designs. Some parts stores have a box of these misc washers and pilots. Something to look into if the new compressor is the same as the one you took back.

Thanks for this info! the block is flat, with the tubes coming out of it. One side of the comp was machined to provide a relief for the washer (oring). The other was 2-3 times as deep, and I had nothing in the sack to match it. The second round is supposed to be a reman, I figure if it's a reman, It's been in use before. We shall see, it's supposed to be in today. Thanks again!

[SCOTI]

Originally Posted by Low Elco

Thanks for this info! the block is flat, with the tubes coming out of it. One side of the comp was machined to provide a relief for the washer (oring). The other was 2-3 times as deep, and I had nothing in the sack to match it. The second round is supposed to be a reman, I figure if it's a reman, It's been in use before. We shall see, it's supposed to be in today. Thanks again!

I recently bought a new R4 compressor from Oreillys manufactured by Murray. The new unit had the previously described 'washer' seals in the package. I'm wondering if what you got was just missing some parts/seals?

The price diff between the reman'd & a new unit was $30 so I bought a new unit.

[Low Elco]

Mine was new, and dig this, I found a package of the "big washer" seals in a completely unrelated box last night. My bad. But, yesterday I also got a new compressor! and it had washers! And it all hooked up, after a bit of a briggle. I also found a great video by Eric The Car Guy on Youtube that explains how to use the manifolds and Vac compressor that I bought. I ran out of time last night, but I pulled Vac on it and left it all night, and still had full vac this AM, so we're gonna shoot the juice to 'er tonight and see what happens. Updates as events warrant!

[foamypirate]

Originally Posted by Low Elco

Mine was new, and dig this, I found a package of the "big washer" seals in a completely unrelated box last night. My bad. But, yesterday I also got a new compressor! and it had washers! And it all hooked up, after a bit of a briggle. I also found a great video by Eric The Car Guy on Youtube that explains how to use the manifolds and Vac compressor that I bought. I ran out of time last night, but I pulled Vac on it and left it all night, and still had full vac this AM, so we're gonna shoot the juice to 'er tonight and see what happens. Updates as events warrant!

The only thing I can add to the EricTheCarGuy video, is to purge the yellow hose of air before you start charging. I've seen the video, and I think he glanced over that step. It's really easy to do, once your refrigerant is flowing into the yellow hose, with both valves still closed on the gauges, just crack the yellow hose fitting at the gauges for a second or two to make sure the hose only has refrigerant in it. This will help keep air (non-condensable), out of the system.

[Low Elco]

Well, I used the ECG vid, and Hatzie's guy's instructions, and my neighbor the diesel mechanic, and, success! 48-50 deg air at the vents with the doors open on an 86 deg day. Drove it to work, it's supposed to be 91 today, we'll see how cool she is!

[foamypirate]

Originally Posted by Low Elco

Well, I used the ECG vid, and Hatzie's guy's instructions, and my neighbor the diesel mechanic, and, success! 48-50 deg air at the vents with the doors open on an 86 deg day. Drove it to work, it's supposed to be 91 today, we'll see how cool she is!

Right on!

I'm still getting used to having A/C in my truck. Still blows my mind every time I get in, haha. I guess driving squares for 7 years without A/C in Texas will do that to you.

[SCOTI]

Originally Posted by foamypirate

Right on!

I'm still getting used to having A/C in my truck. Still blows my mind every time I get in, haha. I guess driving squares for 7 years without A/C in Texas will do that to you.

In my book, there's a law against that. No reason to do w/o ac when these trucks were equipped w/the hardware.

[foamypirate]

Originally Posted by SCOTI

In my book, there's a law against that. No reason to do w/o ac when these trucks were equipped w/the hardware.

After getting it up and running in this truck, I certainly wish I had tackled it earlier on the others. It wasn't nearly as difficult or complex as I initially felt it would be.

[Low Elco]

Me too. Not so bad, once you're in there. The next one's gonna be a party. '70 Chev PU, Classic auto air integrated with the LS swap truck compressor via custom hoses. Fun fun.

[foamypirate]

Originally Posted by Low Elco

Me too. Not so bad, once you're in there. The next one's gonna be a party. '70 Chev PU, Classic auto air integrated with the LS swap truck compressor via custom hoses. Fun fun.

I don't have aftermarket A/C, but I did have the fun of having custom hoses made to work with my LS swap! I put the loop in the suction side to help avoid slugging the low mount compressor. In retrospect, after learning how an accumulator works, I don't believe it's needed at all. Would look much cleaner without, for sure. I used the compressor ends from a 2005 Sierra Denali (donor for the engine). The A/C supply store cut the factory crimp off and brazed on new barbs, and crimped new hose and hose ends appropriate for the truck. I was even able to utilize the factory pressure transducer location in the discharge line to get PCM control of my fans in regards to A/C. You can just barely see the barrel of the sensor between the two heater hoses.