W123 AC O ring size list? - PeachParts Mercedes-Benz Forum

JHZR2 · #1 09-02-2018, 10:03 PM

I’m going to open the system in my 82 300cd, so I’ll want to replace o rings.

Perhaps I’m not searching for the right terms, I’m not finding a list.

I did find the kit Santech 227598633, but some reviews indicate it doesn’t have everything needed.

Does anyone have a rundown of the underhood o rings for a W123?

Thanks!

BirthdayBenz · #2 09-03-2018, 08:26 AM

I just rebuilt most of my AC system.

Used these: https://www.amazon.com/gp/product/B01NBB7AQY/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1

Diseasel300 · #3 09-03-2018, 09:47 AM

Not sure about the W123, but when I did my W126, I used a Santech package (not sure if it's the same one, it also had the seals for the later compressors) and had enough O-rings to do every joint in the system with plenty left over.

JHZR2 · #4 09-03-2018, 12:19 PM

Thanks for the leads. On the big ac thread on here, I noted where it said that despite the car having metric fasteners, all the AC is SAE. I don’t know if this is across the board true, or just certain components.

Also not sure if o rings are intrinsically metric vs sae, or more common than fasteners.

I really don’t want to buy a kit of 270 rings I may never use, but I also don’t want to be on a wild goose chase, or worse, use slightly the wrong size and then have a leak.

Thanks!

funola · #5 09-03-2018, 05:18 PM

Do not buy this kit https://www.amazon.com/gp/product/B01NBB7AQY/ref=oh_aui_detailpage_o07_s00?ie=UTF8 It has too many sizes you do not need but do not have all the sizes you do need. W123 A/C needs #6, 8, 10, 12 SAE o-rings and SAE wrenches except 2 fittings on the expansion valve, which needs 17 & 22 mm wrenches of which there are no SAE equivalents.

BillGrissom · #6 09-03-2018, 06:39 PM

The linked HBNR O-ring kit looks just like the one I bought at Harbor Freight, maybe $6 on sale. One of my R-4 compressors uses O-rings. I think I used HBNR ones from that kit, but I also have 2 buna-N (nitrile) kits (SAE and metric) and might have used those since using compatible refrigerant (Duracool and PAO 68 oil). Don't use buna-N w/ R-134a.

JHZR2 · #7 09-04-2018, 12:04 AM

Quote:

Originally Posted by funola

Do not buy this kit https://www.amazon.com/gp/product/B01NBB7AQY/ref=oh_aui_detailpage_o07_s00?ie=UTF8 It has too many sizes you do not need but do not have all the sizes you do need. W123 A/C needs #6, 8, 10, 12 SAE o-rings and SAE wrenches except 2 fittings on the expansion valve, which needs 17 & 22 mm wrenches of which there are no SAE equivalents.

Thanks! When you say SAE wrenches, I assume you mean line wrenches (crow foot or standard)?

Or do regular combination sae wrenches work fine enough?

funola · #8 09-04-2018, 03:29 PM

Quote:

Originally Posted by JHZR2

Thanks! When you say SAE wrenches, I assume you mean line wrenches (crow foot or standard)?

Or do regular combination sae wrenches work fine enough?

I meant SAE combination open end wrenches. Long ones provides mechanical advantage.

JHZR2 · #9 09-04-2018, 04:05 PM

Thanks for the clarification. Wasn’t sure if there’s a benefit to line wrenches...

math · #10 01-19-2019, 03:27 PM

Quote:

Originally Posted by funola

Do not buy this kit https://www.amazon.com/gp/product/B01NBB7AQY/ref=oh_aui_detailpage_o07_s00?ie=UTF8 It has too many sizes you do not need but do not have all the sizes you do need. W123 A/C needs #6, 8, 10, 12 SAE o-rings and SAE wrenches except 2 fittings on the expansion valve, which needs 17 & 22 mm wrenches of which there are no SAE equivalents.

Any idea on how many of each o ring is needed for a full redoing of the ac system > ?