My Custom 1980 W116 300SD Project Part 2 - Page 5 - PeachParts Mercedes-Benz Forum

Squiggle Dog · #61 05-06-2018, 08:44 PM

I've been wracking my brain over all the changes I'm having to make in the wire harness, but I'm pretty close to being done making those changes. Sadly, I'm going to have to splice several wires because ALL of the wires in the donor harness going from the blower motor dial switch to the blower motor were cut at the firewall (I still don't understand why I did this years ago when I was extracting the harness from the donor car). Fortunately, the wires at the blower motor resistor plug on my car are the same colors and size and are just long enough to reach them (in the ACCII system, these wires connect from the blower motor resistor plug to the servo, so they are very short).

It won't really matter because they will work fine and not be seen since they will be wrapped with new cloth tape, but I'm the type of person that likes to do things 100% perfectly and it would have only taken a couple extra minutes to pull the wires through the firewall instead of cutting them while saving me time and effort when installing them in my car. I must have thought they wouldn't be needed when I pulled the harness from the donor car six years ago (yet when I have sold manual climate control systems to people, I managed to keep this part of the harness intact).

Speaking of this, a grey 1979 W116 300SD with a red interior was on eBay a few months ago. I sold the previous owner the manual climate control and red interior which he actually seems to have been successful in installing, and it appears he left the car's wire harness intact, unplugged unused wire connectors, and added the ones he needed--while my approach is remove the wrapping, remove unneeded wiring, add needed wiring, and then wrap it all back up. He also painted the car himself and installed Euro bumpers. Whoever bought that car got a real gem.

I installed a 16" auxiliary fan from a second generation W126 and read that I need to upgrade the wire harness to handle the higher amperage of the fan, but the W126 uses the exact same wire size (2,5mm²) and colors (black and brown) as the W116, so it's not necessary to rewire the fan. However, I want to wire the auxiliary fan so it comes on with the compressor instead of the pressure switch, for improved air conditioning performance. ROLLGUY sells a plug-and-play wire harness with relay that will accomplish this--and after thinking about it, I think I understand exactly how it works (power from the wire going to the compressor attaches to a connector in the harness and travels to the relay in the harness, which lets power flow from where it's connected at the glow plug relay, through a 20 amp inline fuse, down to where it plugs into the compressor, powering the compressor, while power also flows from the harness and connects to the auxiliary fan, where it powers it [and the auxiliary fan plug on the body is not used] while the ground wires at the auxiliary fan and compressor wiring connect to the harness and then travel back to the relay location where it grounds to the body with a screw.).

However, I also want the auxiliary fan to come on with the coolant temperature switch on the engine so it will lower coolant temperatures if the engine runs too hot. I'm trying to figure out that one so I don't lose this function by getting the auxiliary fan to run with the compressor. If I run the wire from the coolant temperature switch to the auxiliary fan, it will cause the compressor to kick on (which I don't want) unless I run that wire to the relay in such a way that it will only activate the auxiliary fan...

I've been reading through air conditioning threads (many of which have diminished effectiveness due to Photobucket images not showing up) and was considering replacing the expansion valve (TXV) with an orifice tube (OT) and adding an accumulator (to keep liquid refrigerant from reaching the compressor). However, by the time I was done reading the threads, I think that I'd be best off retaining the expansion valve because they seem to be safer and more effective. Adding an accumulator may be beneficial as it would help protect the compressor from liquid refrigerant reaching it, and it may increase performance (some W126s have accumulators). However, it would be another part for which I would need to find space, it would frustrate the hose routing I have planned, and it may not be needed in an expansion valve system. Right now adding an accumulator is a "maybe" but I'd rather not add one if it's not going to be of any real benefit.

I think that I will use refrigerant R-12. Even though more R-12 has to be used than R-134a when charging a system, R-12 seems to perform better. R-12 seems to still be available for purchase, one way or another. I live in Arizona and imagine it's probably easier to get it here due to the hot climate and close proximity to Mexico where R-12 is still being produced. I had considered hydrocarbon refrigerants like Duracool and Freeze-12, as I had read that they were both superior to R-12 and they are easy to purchase. However, I think that this is pure marketing and while they may work as well as R-12 for a while, it seems they have a short longevity due to different particle sizes. They are also flammable. I was under the impression that R-12 was also flammable, but apparently it's not. This video hits close to home; it's in Phoenix and toward the end a W116 that was using a hydrocarbon refrigerant blew up: https://www.youtube.com/watch?v=ANtAbkKrOuI&feature=related .

R-12 seems to be the best option and is even better for the environment than R-134a. I had considered using R-134a since I wanted to "get with the times" and use a "more environmentally-friendly refrigerant" and would be servicing the ENTIRE system anyway with parts compatible with and suited for use with R-134a. With a parallel-flow condenser, larger auxiliary fan, and Sanden compressor, I'd probably have as good or better than stock air conditioning running R-134a. However, I'd have even better performance using R-12, so why not go with that? I want the best possible air conditioning in my car since I live in an extremely hot climate (120F summers and 100F+ most of the year) and have the opportunity and ability to alter anything necessary to increase the performance.

Since access at the compressor is limited, I am going to add inline service ports to the high and low-pressure hoses. The ones I ordered have R-134a fittings on them. This may be a problem when it comes time to charging with R-12. I imagine there is a way around this, but I looked for inline service ports with R-12 fittings, and it seems no one sells them? I did see some inline ports that are for switches, and it almost looks like maybe those could be used for R-12 fittings. Hmmm...

I would, however, like to see if there is a compressor oil which is compatible with all refrigerant types in case laws and availability change years later and I'm forced to use R-134a or something else, and won't have to flush the system of the old oil to change refrigerant types.

ROLLGUY · #62 05-07-2018, 11:38 AM

I was thinking about your need to have the aux fan activate when the compressor is on, as well as when engine temp increases. I am by no means an electrical engineer, but I think properly placed diode/s would allow both switches (thermal switch in the head, and compressor fan relay) to energize the fan when either or both are called for. As far as inline charge port fittings go, I have R12 high side (#8 hose), and can get the low side (#10). I can also make A/C hoses. If you are so inclined, you can purchase a Mastercool crimper and the materials and make your own hoses. One thing nice about the W116, is that all the A/C hoses and connections are on the left side. If you are going with the Sanden, charge port 90 degree fittings are also available. The oil I use for both R12 and 134a is Ester. It is compatible for both, but a thorough flushing of the system, and draining of the compressor is suggested. If you are going to use a P. F. condenser, then only the evaporator will need to be flushed. Everything else will be new.

Squiggle Dog · #63 05-07-2018, 03:37 PM

ROLLGUY, using diodes is a good suggestion. I spent several hours yesterday pondering it over, and I think I've figured out a way to make it work using the original auxiliary fan relay, which is:

In early manual W116 climate control systems, the compressor clutch is powered on directly by a blue and green 2,5mm² wire coming from the temperature dial switch (no switches of any kind were used between the temperature dial switch and compressor; pressure switches were not yet in use). A blue 1mm² wire is connected to this wire at the temperature dial switch and connected to the RPM stabilization relay which would raise the idle in gasoline-powered models so that whenever the compressor clutch was engaged, the engine's idle speed would be raised to counteract the extra load.

To power the auxiliary fan whenever the compressor clutch is powered:

1. The existing red 2,5mm² wire at fuse #2 (which has only one wire, as its sole purpose on a W116 is to power the auxiliary fan) connects to terminal 30 of the auxiliary fan relay, providing it with a power source.

2. The extra blue 1mm² wire coming from the temperature dial switch of the manual climate control which would have gone to the RPM stabilization relay on a gasoline-powered model will now connect to terminal 86 of the auxiliary fan relay, which will switch on the relay whenever the temperature dial switch is turned on AND the ETR switch does not disable it.

3. A brown 0,75mm² ground wire at terminal 85 of the auxiliary fan relay will complete the circuit which will make switching on of this relay possible by a signal from the blue 1mm² wire coming from the temperature dial switch.

4. When the auxiliary fan relay is switched on by power from the temperature dial switch, it will allow power from fuse #2 to travel through the auxiliary fan relay and out of terminal 87 where it will travel through the existing black 2,5mm² wire toward the auxiliary fan.

5. The wires which went from the auxiliary fan relay to the refrigerant temperature switch on the receiver drier will be removed along with the temperature switch itself. The wires which went from the auxiliary fan relay to the coolant temperature switch on the thermostat housing will also be removed.

Doing the above should power on the auxiliary fan whenever the compressor clutch is engaged, however, I will be using the pressure switch on the drier, which will disengage the compressor clutch whenever refrigerant pressures are too high. However, the auxiliary fan's power wire will be connected before the pressure switch, therefore the auxiliary fan will remain running and reducing refrigerant pressures even when the pressure switch causes the compressor clutch to disengage.

To power the auxiliary fan whenever the engine's coolant temperature reaches 100C/212F:

1. An added-on 2,5mm² or 4mm² wire (possibly black in color) will be added to fuse terminal #2 (of which sole purpose was to provide power to the auxiliary fan through the auxiliary fan relay). This wire will then go to the coolant temperature switch on the thermostat housing which switches on when coolant temperatures reach 100C/212F and then switches back off once the coolant lowers down to 95C/203F.

However, the original coolant temperature switch (part number 006 545 14 24, red color, M4X1.5X1 threads, on at 100C/212F, off at 95C/203F) is a single-pin unit which grounds to the engine through the thermostat housing and is not suited for what I need.

I found that there is a coolant temperature switch (part number 006 545 15 24, red color, M4X1.5X1 threads, on at 100C/212F, off at 95C/203F) which has two pins and grounds from the second pin after going through the wires which complete the circuit.

2. Another 2,5mm² or 4mm² wire will go from the second pin of this 2-pin coolant temperature switch replacement and will run back through the firewall and will connect to the black 2,5mm² wire which powers the auxiliary fan (inside the firewall before it reaches the loom after the firewall so the part of the auxiliary fan wire harness in the engine compartment will be left untouched).

One thing I wonder about: Can the coolant temperature switch handle the full load of the auxiliary fan running through it? The original design is for it to switch on a relay, which then draws power from the fuse box to power the auxiliary fan, so there is very little current running through the coolant temperature switch and even small 0,75mm² wires are used. However, what I want to do is run the full load of the auxiliary fan through it (and of course using much larger wires). I just hope the switch can handle that much current.

3. If the coolant temperature reaches 100C/212F, the coolant temperature switch on the thermostat housing will switch on and allow power from fuse #2 to flow through it and toward the auxiliary fan, thus powering it. When coolant temperatures drop to 95C/203F, the coolant temperature switch will shut off and thereby shut off the auxiliary fan.

By doing the above, the auxiliary fan will always be powered by fuse #2, which is solely used for powering on of the auxiliary fan. A 16 amp fuse is stock, however, I have the freedom to install a larger fuse if necessary because of the higher amperage of the upgraded 16" second generation W126 auxiliary fan and since there is nothing else being powered by fuse #2.

Increasing the size of the wires in the auxiliary fan wire harness is not necessary because even the second generation W126 uses the same size 2,5mm² black and brown wires. However, because the added wires which will run between fuse #2, the coolant temperature switch, and the auxiliary fan power wire will be rather long as the coolant temperature switch is located on the opposite side of the engine compartment than the auxiliary fan wire harness, I may use larger 4mm² wires to and from the coolant temperature switch in order to keep down the wire resistance.

If the auxiliary fan is being powered by the coolant temperature switch, it cannot flow back and inadvertently power the compressor when the air conditioning is not on because the auxiliary fan relay which is switched on only by the power wire coming from the temperature dial switch will be switched off.

When the air conditioning is switched on and the auxiliary fan is running with it, if then the coolant temperature switch engages, though there will be two powered circuits colliding, because both of their power sources is from fuse #2, there should be no consequences except possible decreased wire resistance as the fan would be powered by two wires instead of one. If the coolant temperature switch shuts off, the auxiliary fan will stay running until the either the air conditioning is shut off or the ETR valve shuts it off. Or, if the air conditioning is switched off, the auxiliary fan will stay running until the coolant temperature switch shuts off. The power cannot backflow into anything and cause inadvertent powering on or damage.

I still think your wire harness and relay to power the auxiliary fan whenever the compressor is engaged is brilliant, due to it being plug-and-play, easy to install, and easily removed if desired. As long as a person doesn't wish for the auxiliary fan to come on with increased coolant temperatures, that's the way to go. And so far I have not ever observed increased coolant temperatures in my car--even in stop-and-go long commutes in 120F Phoenix traffic--with the exception of when I was going up the steep grade at The Grapevine in California at 70 MPH while returning from Washington with my car fully loaded inside and out.

So, most people probably don't need the function of the auxiliary fan coming on with increased coolant temperatures anyway, and what I'm planning to do requires drastic measures which is beyond the scope of many people--even most mechanics aren't going to spend hours/days figuring this stuff out. But, I'm already so deep into it with my manual climate control conversion, so I might as well do as much as I can.

I'd be interested in seeing pictures of the #8 and #10 inline ports with R-12 fittings that you have. I was just going to take my hoses to a hose shop to have them crimped, but I might possibly purchase a Mastercool hose crimper (though I don't really have the money to spend and there is a possibility I might have to have a shop weld on new pipe ends by the expansion valve connection and the condenser inlet connection).

I already purchased and am waiting on a 180 degree suction fitting and a 45 degree discharge fitting; I think they will work. I have 90 and 120 degree fittings and they didn't work for my application; both have charge ports and there isn't enough room in the compressor area for them to be be practical, so that's why I want to use inline ports. The W116 hose routing is very different from the W123 and W126. New #8 and #10 barrier hose is also on the way.

I have the evaporator out of the vehicle and will be cleaning it well inside and out. Everything else, as you say, will be new. Thanks a lot for the advice.

ROLLGUY · #64 05-07-2018, 07:45 PM

It is awesome that you are able to figure out how to make the fan work from both sources. Does not the factory W116 climate control unit (automatic and/or manual) have an A/C compressor on/off switch? I don't know about the manual, but I thought the automatic system did in fact have the switch. If you are using a rear port Sanden, there should be enough room for 90 degree #8 & #10 charge port fittings on the rear of the compressor. I am sure these fittings are readily available. If at all possible, use steel fittings. I have had a couple aluminum fittings break from the vibration of these engines. Every combination of fitting that I have needed is available in steel except the inline charge port fittings for R12. I have them in steel for 134a. I have #8 (high side) inline R12 charge port fittings, but would have to order one for #10 (low side).

ROLLGUY · #65 05-07-2018, 07:59 PM

It seems that all R12 fittings are aluminum, and no steel fittings can be had. For this application (fitting with a length of rubber hose on each end), engine vibration is not a problem.

dude99 · #66 05-07-2018, 08:11 PM

Quote:

many of which have diminished effectiveness due to Photobucket images not showing up

There is a chrome plugin that makes the photobucket links work again. I'm not a fan of chrome but keep a copy of it installed on my computer with the plugin just for viewing picture heavy threads.

and as always, great work!

Squiggle Dog · #67 05-07-2018, 08:29 PM

ROLLGUY,

The factory W116 ACCII climate control unit has a compressor on and off switch. The factory W116 manual climate control has one too, but it's very different in that it's a rotary dial and has the ETR switch integrated into it. So, it has an off position, and when it is put on the coldest temperature setting, it runs the compressor the entire time unless either the ETR switch or the pressure switch (which early W116s did not have) shuts it off.

When the temperature dial is placed in one of the middle settings, it acts as an adjuster for the ETR switch so it will shut off the compressor at a higher temperature. It also has a vacuum valve which opens and closes the recirculating air flap at the blower motor housing.

I have a rear port Sanden, but when I use 90 degree fittings (and they have to reach up toward the driver side fender) things are in their way and it makes an awkward angle for the hoses.

The 180 and 45 degree fittings just arrived, so I can test them for fitment. They are both aluminum, though. I was hoping that would be good enough since there will be a large "loop" in each of the hoses. If nothing else, I'll know if the angles are correct.

That's great that you have inline ports with R-12 fittings. I'll have to asses what I have and see what will work and what won't.

dude99, Thanks for the information about the Photobucket links.

ROLLGUY · #68 05-07-2018, 08:59 PM

Quote:

Originally Posted by Squiggle Dog

ROLLGUY,

The factory W116 ACCII climate control unit has a compressor on and off switch. The factory W116 manual climate control has one too, but it's very different in that it's a rotary dial and has the ETR switch integrated into it. So, it has an off position, and when it is put on the coldest temperature setting, it runs the compressor the entire time unless either the ETR switch or the pressure switch (which early W116s did not have) shuts it off.

When the temperature dial is placed in one of the middle settings, it acts as an adjuster for the ETR switch so it will shut off the compressor at a higher temperature. It also has a vacuum valve which opens and closes the recirculating air flap at the blower motor housing.

I have a rear port Sanden, but when I use 90 degree fittings (and they have to reach up toward the driver side fender) things are in their way and it makes an awkward angle for the hoses.

The 180 and 45 degree fittings just arrived, so I can test them for fitment. They are both aluminum, though. I was hoping that would be good enough since there will be a large "loop" in each of the hoses. If nothing else, I'll know if the angles are correct.

That's great that you have inline ports with R-12 fittings. I'll have to asses what I have and see what will work and what won't.

dude99, Thanks for the information about the Photobucket links.

"I was hoping that would be good enough since there will be a large "loop" in each of the hoses" I think that would be more of a problem, and I hope I can explain my reasoning behind it. If the curvature of the hose is in line with it's natural routing, there should be no pressure on the aluminum fittings. If there is a "loop" or any excess hose, it will put lateral pressure (hose wanting to go straight) on the fitting. This will surely cause an aluminum fitting to break. With steel fittings, any excess length or bends in the hose will have no effect on the fittings. The hose will eventually take a set. I had this problem with the first retrofit I did. The A/C shop made the hoses for me, and all they had was aluminum fittings. It was less than a month later, I went back for a vac and charge after finding and replacing the aluminum fittings with steel (got the crimper and a supply of hose for myself).

Squiggle Dog · #69 05-07-2018, 09:37 PM

Quote:

Originally Posted by ROLLGUY

"I was hoping that would be good enough since there will be a large "loop" in each of the hoses" I think that would be more of a problem, and I hope I can explain my reasoning behind it. If the curvature of the hose is in line with it's natural routing, there should be no pressure on the aluminum fittings. If there is a "loop" or any excess hose, it will put lateral pressure (hose wanting to go straight) on the fitting. This will surely cause an aluminum fitting to break. With steel fittings, any excess length or bends in the hose will have no effect on the fittings. The hose will eventually take a set. I had this problem with the first retrofit I did. The A/C shop made the hoses for me, and all they had was aluminum fittings. It was less than a month later, I went back for a vac and charge after finding and replacing the aluminum fittings with steel (got the crimper and a supply of hose for myself).

The way I had planned this is the 180 degree low pressure fitting would point toward the front of the vehicle and would then gradually curve upward at the area behind the headlight and then curve back toward the hose holder on the inner fender and into the firewall. Then the 45 degree high pressure fitting would point toward the back of the vehicle and slightly upward and then the hose would curve up and then toward the front of the vehicle and then curve down and attach to the condenser inlet pipe.

I was wanting to design a lot of give in the hoses so that the fittings wouldn't be so affected by vibration and if the compressor ever needed to be removed from the engine and set aside.

It sounds that I should get steel compressor fittings, though. The aluminum inline service ports with R-12 fittings should be adequate.

ROLLGUY · #70 05-08-2018, 12:10 AM

Quote:

Originally Posted by Squiggle Dog

The way I had planned this is the 180 degree low pressure fitting would point toward the front of the vehicle and would then gradually curve upward at the area behind the headlight and then curve back toward the hose holder on the inner fender and into the firewall. Then the 45 degree high pressure fitting would point toward the back of the vehicle and slightly upward and then the hose would curve up and then toward the front of the vehicle and then curve down and attach to the condenser inlet pipe.

I was wanting to design a lot of give in the hoses so that the fittings wouldn't be so affected by vibration and if the compressor ever needed to be removed from the engine and set aside.

It sounds that I should get steel compressor fittings, though. The aluminum inline service ports with R-12 fittings should be adequate.

Just the weight and length of the hose is enough to break the fitting. You will notice that even being steel, the factory manifold is bolted tight to the compressor. If you could mount the two hoses solid to the compressor, you might have a chance (although it would be a slim one in my opinion) to keep the aluminum fittings from breaking. Especially a 180 degree fitting, I can't see that lasting long. Trust me in this- aluminum fittings just don't work on the compressor. The inline charge port fittings are fine, as long there is some solid attachment on both sides.

Squiggle Dog · #71 05-08-2018, 01:53 AM

I mocked-up the hoses to show how I'm planning to run them. I agree with you that I should use steel fittings. The 180 and 45 degree fittings seem to work pretty close to the way I'd like them, except the 180 degree fitting is a little taller than I planned and there isn't a lot of clearance for movement of the compressor during belt replacement. If I had a 180 degree fitting that laid closer to the compressor, it would give more clearance.

This is where I'd like to mount the inline ports. Actually, I have been considering installing an accumulator with an R-12 fitting in place of the low pressure port in order to protect the compressor from liquid refrigerant reaching it and adding extra cooling capacity to the system. However, finding one with an R-12 fitting may be difficult (both now and in the future if it needs replacing) and it may be overkill on an expansion valve system, not to mention cumbersome. Sure, Mercedes didn't use them until the W126? but it could potentially save the compressor. I don't know.

ROLLGUY · #72 05-08-2018, 11:18 AM

Looking at the photos, you would be better off going with a steel 90 on the low side, and the hose going straight up to the connection in the cabin. Of course you would put the charge port fitting somewhere in the middle of th run, or even better, close to the firewall. You would not need to worry about fittings breaking, as the hose would retain it's natural curl the way it is routed. You have the high side just about the way I would run it. Of course steel fittings are a must on the compressor. The W116 is not much different than a W126 with the placement of the components. The exception being the W126 has a bulkhead fitting at the forward firewall, whereas the W116 has a continuous hose from the compressor to the TXV. Your car has standard fittings at the condenser and drier, so that makes it easier. The W126 needs hose barbs welded on the factory fittings to make them work. As others have said, you are doing a great job, and I agree. You have been encouraging to many of us here with the quality of work you are doing. Your posts are thorough and inspiring, and always a pleasure to read. Keep up the good work!

Squiggle Dog · #73 05-08-2018, 07:19 PM

Thanks, ROLLGUY. I will be using steel compressor fittings for sure. They are difficult to find (let me rephrase this--they are difficult to find in the size and angles I want). I'm still working on deciding on the ideal angles. I was wanting to make the low pressure hose come out front and then loop back toward the firewall because that's the way it was originally and then the holder bracket would be retained.

The bigger reason is there would be more hose length, which would allow the compressor to be unbolted and dropped down out of the way if needed without removing the hoses. But, W126s seem to do it the way you are describing, and I may end up having to do it this way.

ROLLGUY · #74 05-08-2018, 07:52 PM

Quote:

Originally Posted by Squiggle Dog

Thanks, ROLLGUY. I will be using steel compressor fittings for sure. They are difficult to find (let me rephrase this--they are difficult to find in the size and angles I want). I'm still working on deciding on the ideal angles. I was wanting to make the low pressure hose come out front and then loop back toward the firewall because that's the way it was originally and then the holder bracket would be retained.

The bigger reason is there would be more hose length, which would allow the compressor to be unbolted and dropped down out of the way if needed without removing the hoses. But, W126s seem to do it the way you are describing, and I may end up having to do it this way.

If you are using steel fittings, and are able to secure the charge port fittings to something, you should have no problem with the added length of hose and routing. I have #8 &#10 45 & 90 degree fittings in stock. If you can't find them, or they are too expensive, please let me know.......Rich

Squiggle Dog · #75 05-08-2018, 08:34 PM

Quote:

Originally Posted by ROLLGUY

If you are using steel fittings, and are able to secure the charge port fittings to something, you should have no problem with the added length of hose and routing. I have #8
45 & 90 degree fittings in stock. If you can't find them, or they are too expensive, please let me know.......Rich

I actually found a source for steel R-12 inline charge ports, so I shouldn't need to secure them: https://www.acparts.com/product/straight-splicer-with-switch-or-service-port-8-1331144/ and https://www.acparts.com/product/straight-splicer-with-switch-or-service-port-10-1331147/ .

The reason I'm so dead-set against using 90 degree fittings is because they don't really work on the W116.

On the high pressure side, no matter how tall or short the 90 degree fitting, the oil cooler hard lines get in the way. The hose could probably still fit through, but when the compressor belt needs to be replaced, the compressor won't have any range of travel. A 45 degree fitting lets the hose come out in an open space where there is lots of room.

On the low pressure side, the oil cooler hard lines are in the way and the hose would be pinched between the oil cooler hard line and the body. This also restricts compressor movement during belt changes.

Here is the steel 180 degree low side fitting I will likely purchase: https://www.acparts.com/product/180-degree-female-o-ring-for-10-1331104/ . These are extremely difficult to find in steel, but here one is. Hopefully it's not out of stock. The aluminum 180 degree one I have hits the oil cooler line bracket and causes problems. However, looking at actual pictures of part number SB1933 (the steel type), they seem to not be as wide and they should fit underneath the oil cooler line bracket. If not, I should be able to squish the fitting together a little to gain some clearance, or I may have to shorten the oil cooler line bracket and flip the clip so the oil cooler lines mount underneath it instead of on top...

They have a steel 45 degree high side fitting, too.

I've been considering adding an accumulator to help protect the compressor against rogue liquid refrigerant sneaking out of the evaporator, but I'd rather not bother installing one. I'm hoping it's totally unnecessary because I don't want to do it, but at the same time, I don't want my compressor to die an early death.