'81 300SD - is this the only AC hose? - Page 2 - PeachParts Mercedes-Benz Forum

Hit Man X · #16 09-09-2018, 09:56 PM

Quote:

Originally Posted by funola

Probably due to operator error. I have a reman 4 Seasons heavy R4 running R12, all original hoses, been running great for 2 summers now.

Probably not.

ROLLGUY · #17 09-10-2018, 10:30 AM

Quote:

Originally Posted by funola

Probably due to operator error. I have a reman 4 Seasons heavy R4 running R12, all original hoses, been running great for 2 summers now.

Quote:

Originally Posted by Hit Man X

Probably not.

From my experience, it could be either or both. There are very few companies doing reman's on R4's, and even fewer manufacturing new ones (Compressorworks may be the only one?). When these compressors were new (80's & 90's), they probably lasted a good long time. They were made with quality (well, as good of quality that could be had at the time) parts made in the USA. I don't think that is the case now. I am sure some of the internal parts in new and reman compressors are made in China. There is also the issue with the clocking of the oil hole in the front housing. I believe this could be a large factor in the longevity (or lack thereof) of new and reman R4's. In most of the GM applications, the compressor was on the top of the engine, with the manifold connection being from the 9 o'clock position to the 3 o'clock position. I am sure the manufacturer put the oil hole in the proper position for the application it was made for. Same with R4's in MB's (different clocking for the front housing).
As for "operator error", this can happen with any brand or type of compressor installation. Many DIY'ers don't know to flush the entire remaining components of the A/C system before installing a new or reman compressor (R4, Sanden or otherwise). Not flushing the system probably accounts for more failed new and reman compressor replacements than is realized. I believe that any quality compressor, installed in a properly flushed system, with the proper type and amount of oil, and non-leaky hoses, should last many years without issues.

A side note about quality compressors: I am having to replace a Sanden compressor for the second time (third compressor) on a customers TD. The first one went bad only after a couple weeks from a bad clutch bearing. It was replaced by a mechanic friend of the customer, and under warranty from the distributor. The second replacement went bad in just a few days from who knows what, so the customer cut the belt. I will be removing it, and replacing it with a third compressor. But not before flushing the entire system (again). It is possible that these new Sanden compressors are made with Chinese parts. They do say "Made in USA" on the label. The earlier Sandens were made in Singapore, and before that, Japan (first generation). All of this will not sway me from installing Sanden compressors. The design is far superior to the R4 in my opinion.......Rich

funola · #18 09-10-2018, 02:15 PM

Quote:

Originally Posted by tyl604

Fun - do you remember exactly how much mineral oil or PAG you put in your new R4 and how many places you need to add oil? I have been reading ads for the reman R4 and they say that the oil in the reman is only for testing purposes and that the new owner must dump it all out and then add new oil.

Thx.

Don't quote me on this. If my memory serves me correctly, it was 8 oz of oil for my 85 300D with stock hoses, evap and condenser. I used Behr/Hella PAO 68 oil + UV dye https://www.behrhellaservice.com/behr-hella-service/assets/media/Compressor_Oils_EN.pdf ,

Yes, I drained the shipping oil out of the reman R4 compressor, then flushed it with PAO 68 oil before installing. I distributed the oil in the system, 2 oz in the compressor (via hose connection by the pwr steering pump), 2 oz in the dryer, 2 oz in the evap, 2 oz in the condenser.

tyl604 · #19 09-10-2018, 03:12 PM

Wow; perfect. Just what I needed.

Thx.

vstech · #20 09-10-2018, 04:21 PM

I recommend reverse flushing the condenser, replacing the txv and cleaning all 5 hoses and the evaporator...

tyl604 · #21 09-10-2018, 04:35 PM

New term; where is the txv? Is this it - where located? https://www.pelicanparts.com/cgi-bin/ksearch/PEL_search_2016.cgi?command=DWsearch&description=ac+txv

A/C Vacuum Actuator
Part #: 000-800-40-75-INT
[ More Info ]

View in Catalog: Cables & Controls

This part fits your 1981 Mercedes-Benz 300SD Sedan

Brand Rating
$68.00

SD Blue · #22 09-10-2018, 04:56 PM

TXV aka...expansion valve.
126-830-03-04

On the W126, it's located in an area above the drivers' foot when resting on the go pedal. I've seen several recommendations about investing in certain crow-ring scanners to make the replacement less painful. Check the a/c tools section on this website.

tyl604 · #23 09-10-2018, 06:00 PM

OK, you got me now. Where do I find a tools section? Looked and found rental tools but no ac section or crow ring scanner.

In over ten years that I have been on the forum I have never known about a tools section.

vstech · #24 09-10-2018, 08:13 PM

Quote:

Originally Posted by tyl604

OK, you got me now. Where do I find a tools section? Looked and found rental tools but no ac section or crow ring scanner.

In over ten years that I have been on the forum I have never known about a tools section.

I am fairly confident he meant spanner not scanner

Autocorrect snafu

https://www.pelicanparts.com/catalog/SuperCat/3335/MBZ_3335_VENTAC_pg5.htm#item17

Click on the Mercedes link at top
Select your vehicle
Choose caragory
Tools is a subheading

tyl604 · #25 09-10-2018, 09:02 PM

Must be an Aussie or a Brit. I have a crows foot but it is pretty large - for a Land Rover 02 sensor. But at least I know what to look for under the dash. Do these go out often? Mine is original.

That part number for txv does not come up in Pelican. I found this Part #: 126-835-06-40-MBZ It looks like a flat plastic piece with four holes. Is this it; what the heck does it fit in? Maybe freon passes through it? Nope - other parts place says it is just a foam insulator.

Maybe he meant this from Amazon https://www.amazon.com/Expansion-Valve-Device-Mercedes-Merkur/dp/B00K38TSOI?keywords=mercedes+expansion+valve+300sd&qid=1536628333&sr=8-1&ref=sr_1_1 I see a URO for $19 and Englehof for $21. Amazon wants about $60.

Diseasel300 · #26 09-10-2018, 09:25 PM

If the expansion valve is working and you're sticking with R12, leave it. They don't often fail, especially if the system was already working. The new replacements have orifice sizing and superheat ratings for R134a. They'll work with R12, but at reduced capacity. If you're converting to R134a, replacing the expansion valve is a good idea, but only if you're converting or your existing one is junk.

SD Blue · #27 09-11-2018, 12:11 AM

Quote:

Originally Posted by vstech

I am fairly confident he meant spanner not scanner

Autocorrect snafu

https://www.pelicanparts.com/catalog/SuperCat/3335/MBZ_3335_VENTAC_pg5.htm#item17

Click on the Mercedes link at top
Select your vehicle
Choose caragory
Tools is a subheading

Yes, thanks John. Autocorrect is a constant nuisance.

tyl604 · #28 09-11-2018, 09:38 AM

Sticking with freon.

ROLLGUY · #29 09-11-2018, 10:43 AM

Quote:

Originally Posted by tyl604

Sticking with freon.

By the way, Freon is a brand name. Many use the term much like they use "Bandaid" for any bandage, "Coke" for any soda, or "Kleenex" for any facial tissue. Freon brand refrigerants are not just R12. Just sayi'n......Rich

https://en.wikipedia.org/wiki/Freon

tyl604 · #30 09-11-2018, 11:24 AM

OK, R12.

Old habits are hard to break.

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