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

tyl604 · #1 09-03-2018, 06:52 PM

My compressor locked up and must be replaced. I had a slight freon leak. Plan on staying with R-4 compressor because it is stock.

So - is the hose below from Pelican the only AC hose that might be leaking? The hose is original and I guess needs to be replaced.

Pic from Pelican.

Diseasel300 · #2 09-03-2018, 08:15 PM

I'm sure the usual suspects will be here screaming about how every hose in the car needs replaced. There are enough datapoints out there that if you don't have dry crusty cracked hoses, they're unlikely to be your leak. The most common leak points are the O-rings in the various joints followed by the shaft seal on the compressor. Look for oily stains on the hoses.

tyl604 · #3 09-03-2018, 09:29 PM

Only asking about the AC hoses; I have a freon leak. Not interested in replacing any other hose.

So is this the only AC hose in the vehicle with freon?

Then again the freon could have escaped from the bad compressor, I guess.

So far I cannot locate anyone in Atlanta who is willing to pressurize the system so I can find the leak. I have four cans of freon and do not want to waste them. Maybe I will just put in the new compressor and then see if I have a leak. Maybe the 38 year old original hose is still OK.

tyl604 · #4 09-03-2018, 10:01 PM

Trying imgur

https://imgur.com/a/qyuDRHQ

https://imgur.com/a/qyuDRHQ OK, finally got it:

AC hose

Diseasel300 · #5 09-03-2018, 10:13 PM

No, that is not the only A/C hose on the car. That's just the compressor hoses. The leak is likely O-rings or the compressor shaft seal.

tyl604 · #6 09-04-2018, 09:25 AM

Got it.

Thx.

Hit Man X · #7 09-04-2018, 06:17 PM

You still need to take into account the liquid line to the evap and from condenser to dryer.

R4s are garbage. You would do yourself a favor with a Sanden conversion. If you need new low and high lines, plus a compressor, you are most of the way there anyway.

tyl604 · #8 09-04-2018, 10:41 PM

Understand

ROLLGUY · #9 09-05-2018, 09:54 AM

Quote:

Originally Posted by Hit Man X

You still need to take into account the liquid line to the evap and from condenser to dryer.

R4s are garbage. You would do yourself a favor with a Sanden conversion. If you need new low and high lines, plus a compressor, you are most of the way there anyway.

Agreed that R4's are garbage, but the liquid lines are bullet proof in these cars, and almost never leak unless damaged somehow. There is the remaining portion of discharge hose from the bulkhead to the TXV. That would be the only other hose that may need to be replaced.

tyl604 · #10 09-05-2018, 10:06 AM

Got it.

Hit Man X · #11 09-05-2018, 11:03 AM

Ah, now I recall why I redid the liquid from condenser to dryer. I had a hole in the condenser and installed a PF.

If I ever bought another SD, first mod would be to junk the R4 system. Really. It is that crappy to me.

BillGrissom · #12 09-09-2018, 05:20 PM

Quote:

Originally Posted by Hit Man X

... R4s are garbage. ...

I know that is the "party line" here, but I have had both a Sanden and R4 on my 1985 300D and both cooled equally fine. BTW, the ambient temperature gets to 110 F here in Sacramento. Neither work well when idling a long time, since the electric fan can't match the airflow from driving. I only dropped the Sanden after the conversion bracket cracked apart so bad I couldn't re-weld it. I use Duracool, which works as well as R-12 (slightly better, in fact). If using R-134A, you might notice a difference, but it is being outlawed so might be foolish to convert to it now.

tyl604 · #13 09-09-2018, 06:09 PM

No, I am an originalist. Still have R12; yes, real freon. Glad to know that someone believes the MB engineers were not crazy when they put in the R4 compressor. I am pretty determined to stick with it.

Are they banning R134a? What is its replacement? Is it compatible with my soon to be purchased R4 compressor?

funola · #14 09-09-2018, 08:00 PM

Quote:

Originally Posted by Hit Man X

...............
R4s are garbage. ...............

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.

tyl604 · #15 09-09-2018, 08:06 PM

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.