A/C recommendations for the MB vehicles - Page 29 - PeachParts Mercedes-Benz Forum

funola · #**421** 05-12-2018, 04:57 PM

Originally Posted by Squiggle Dog View Post
My car doesn't use any O-rings except the ones at the compressor. They are all flare fittings.

Quote:

Originally Posted by Squiggle Dog

By this, I mean from the factory it never used any O-rings except at the compressor. Now it also has O-rings at the condenser because I installed a parallel-flow condenser.

Didn't you say earlier that your car's AC system does not use copper flare seals on any of the AC fittings? Those fittings are called bead lock and they all use rubber o-rings to provide a seal. W123 use four sizes of bead locks fittings, W116 probably the same. The R4 manifold fittings can use either o-rings or stepped washers but it should not be compared to bead lock fittings. They are of totally different designs. The R4 manifold fitting compresses the o-ring or stepped washers between 2 flat plates. Bead lock fittings are totally different and are threaded together.

Why you are talking about flare fittings in other parts of the car other than AC when you are talking AC?

Squiggle Dog · #**422** 05-12-2018, 06:30 PM

Quote:

Originally Posted by funola

Didn't you say earlier that your car's AC system does not use copper flare seals on any of the AC fittings?

Correct. My car does not use copper flare gaskets on any of the air conditioning fittings.

Quote:

Originally Posted by funola

Those fittings are called bead lock and they all use rubber o-rings to provide a seal.

My car did not come with beadlock fittings from the factory. It came with nothing but flare fittings except at the R4 compressor where it used two O-rings.

Quote:

Originally Posted by funola

W123 use four sizes of bead locks fittings, W116 probably the same.

The W116 never used beadlock fittings.

Quote:

Originally Posted by funola

The R4 manifold fittings can use either o-rings or stepped washers but it should not be compared to bead lock fittings. They are of totally different designs. The R4 manifold fitting compresses the o-ring or stepped washers between 2 flat plates. Bead lock fittings are totally different and are threaded together.

Correct.

Quote:

Originally Posted by funola

Why you are talking about flare fittings in other parts of the car other than AC when you are talking AC?

You had said that you didn't think the flare fittings would seal on their own without flare gaskets. I pointed out some other systems of the vehicle which use this type of fitting to show that it does work.

funola · #**423** 05-12-2018, 07:48 PM

Quote:

Originally Posted by Squiggle Dog

Correct. My car does not use copper flare gaskets on any of the air conditioning fittings.

My car did not come with beadlock fittings from the factory. It came with nothing but flare fittings except at the R4 compressor where it used two O-rings.

The W116 never used beadlock fittings.

(.................)

So your car's AC system use flare fittings (does not use beadlock fittings), the flare fittings does not use copper flare seals. Do you have pics of such flare fittings? Not trying to be a PITA. Just want to learn something new.

Squiggle Dog · #**424** 05-12-2018, 11:32 PM

Quote:

Originally Posted by funola

So your car's AC system use flare fittings (does not use beadlock fittings), the flare fittings does not use copper flare seals. Do you have pics of such flare fittings? Not trying to be a PITA. Just want to learn something new.

Here are the stock flare fittings. There wasn't a single flare gasket in them, though another W116 owner reported finding one at their expansion valve--who knows if it was put in at the factory (maybe to fix a leaking connection), or later on by a mechanic.

Here is the picture from EPC. It doesn't show the flare gaskets as being available. I have a theory that they used them on early cars and then stopped using them at the W116 because they felt comfortable enough with the natural seal of the flare fittings that they felt the flare gaskets weren't required. I can buy flare gaskets that fit, and was just deciding whether or not to use them.

Diseasel300 · #**425** 05-12-2018, 11:40 PM

Quote:

Originally Posted by Squiggle Dog

Here is the picture from EPC. It doesn't show the flare gaskets as being available. I have a theory that they used them on early cars and then stopped using them at the W116 because they felt comfortable enough with the natural seal of the flare fittings that they felt the flare gaskets weren't required. I can buy flare gaskets that fit, and was just deciding whether or not to use them.

Flare fittings generally don't use any sort of gasket. The mating surfaces typically fit tight enough that they're gas tight. I'd suspect the washers are there as a repair item for damaged sealing faces, not something that's really required. It seems like adding them would make for more potential leak points.

Squiggle Dog · #**426** 05-12-2018, 11:59 PM

Quote:

Originally Posted by Diseasel300

Flare fittings generally don't use any sort of gasket. The mating surfaces typically fit tight enough that they're gas tight. I'd suspect the washers are there as a repair item for damaged sealing faces, not something that's really required. It seems like adding them would make for more potential leak points.

Yeah, that's what I'm trying to decide; will they help or hurt? I'm most likely ordering a new expansion valve (don't know if it's a wear item), will be ordering a new drier, and had some new hard lines made (already installed). So, all the flare connections will be brand new except for the evaporator and the high pressure hose fittings. I'm just hoping there's nothing screwy with the fit with the new hard lines I had made.

funola · #**427** 05-13-2018, 12:06 AM

Quote:

Originally Posted by Squiggle Dog

Here are the stock flare fittings. There wasn't a single flare gasket in them, though another W116 owner reported finding one at their expansion valve--who knows if it was put in at the factory (maybe to fix a leaking connection), or later on by a mechanic.

Here is the picture from EPC. It doesn't show the flare gaskets as being available. I have a theory that they used them on early cars and then stopped using them at the W116 because they felt comfortable enough with the natural seal of the flare fittings that they felt the flare gaskets weren't required. I can buy flare gaskets that fit, and was just deciding whether or not to use them.

Those sure look like flare fittings! Are they brass? The small line looks like copper made with a flaring tool. What other Mercedes models use flare fittings for AC? Are they same as fractional size flare fittings used in plumbing such as 1/4, 3/8, 5/8, 3/4"?

Squiggle Dog · #**428** 05-13-2018, 01:38 AM

Quote:

Originally Posted by funola

Those sure look like flare fittings! Are they brass? The small line looks like copper made with a flaring tool. What other Mercedes models use flare fittings for AC? Are they same as fractional size flare fittings used in plumbing such as 1/4, 3/8, 5/8, 3/4"?

They are brass flare fittings. I think every Mercedes made before the W123 had flare fittings for the air conditioning. The R/W107, W108, and W114/115 used them for sure. I imagine the W110 and W111 did as well. I took a look at my 1967 fintail wagon and the hoses are clamped directly to the drier with hose clamps. Everything else is a flare fitting.

Also, these flare fittings are SAE thread and I believe the flare has a 45 degree angle.

funola · #**429** 05-13-2018, 11:54 AM

Quote:

Originally Posted by Squiggle Dog

They are brass flare fittings. I think every Mercedes made before the W123 had flare fittings for the air conditioning. The R/W107, W108, and W114/115 used them for sure. I imagine the W110 and W111 did as well. I took a look at my 1967 fintail wagon and the hoses are clamped directly to the drier with hose clamps. Everything else is a flare fitting.

Also, these flare fittings are SAE thread and I believe the flare has a 45 degree angle.

Didn't know flare fittings were ever used in Mercedes AC systems until I saw yours. What about other 80's European car manufacturers? Did they use flare in AC? Why did Mercedes switch to beadlocks? Is it to conform to the rest of industry, not because beadlock is superior?

I can see advantages to SAE brass flare fittings vs beadlock in the US. More readily available, lower price, can be sweated to copper lines. Heck, you can make your own lines using copper, no need for a crimper, just a propane torch. Need to mount/ support the copper lines with dampers so they don't crack from vibration.

Saw this comment in HVACTalk

"I use copper flare gaskets
But only on brass-to-brass flares.

What is the gain in using them inside a regular copper end-flare?

PHM"

Makes sense. Copper is softer than brass. Since the brass flare fittings in your car has been opened, the sealing surfaces is no longer perfect. A copper gasket will help in providing a good seal. I would suggest using them.

ROLLGUY · #**430** 05-13-2018, 12:11 PM

Is it possible that since most of the A/C equipped car buying public was in the USA, that MB sourced the equipment from the USA? They did buy the "Evil Servo" technology from Chrysler, so I could imagine the rest of the A/C components to be sourced from the US. Many A/C systems in the 60's and 70's were aftermarket (US made) for Japanese cars as well. Just thinking out loud....Rich

Squiggle Dog · #**431** 05-13-2018, 02:15 PM

I think the switch to beadlock fittings had a lot to do with air conditioning components switching to aluminum from steel or brass. Aluminum doesn't seem to lend well to flare fittings. Since for some reason the entire industry switched to aluminum components, and thus the use of beadlock fittings, I imagine Mercedes followed suit due to supplier availability.

Mercedes seemed to source most of their air conditioning parts from USA suppliers. The USA has their own laws and standards requiring automotive air conditioning systems. In the W110/111 fintails (which I think were the first Mercedes chassis to be offered with air conditioning), the vehicles were designed with German Behr air conditioning units. But, these were not up to USA standards, so for cars being sold in North America, the Behr units were substituted for Kuhlmeister units made in the USA by Thermo King with USA-made York compressors.

When Mercedes began integrating air conditioning into their vehicles instead of it being just a standalone under-dash unit (late production W108), they must have found it simpler to just use USA-made components so they could build them all one way and sell them anywhere since the USA was likely the highest purchaser of air conditioned vehicles.

The ACCII automatic climate control system used in the R/W107, W116, and early W123 was designed by Chrysler and used in their cars starting in 1971. Mercedes adapted it for use in their own vehicles in 1976.

BillGrissom · #**432** 05-13-2018, 11:49 PM

Quote:

Originally Posted by ROLLGUY

... I could imagine the rest of the A/C components to be sourced from the US. Many A/C systems in the 60's and 70's were aftermarket (US made) for Japanese cars as well. ...

Agree. Now that I think about it, the after-market AC systems in my 1965 Dodge Dart and 1965 Chrysler Newport use flare fittings at the under-dash knee-knocker climate boxes. They have an expansion valve w/ remote gas temperature tube which looks just like squiggle's photo.

Rather than compatibility w/ U.S., perhaps AC was mostly for the U.S. market. U.S. cars didn't get factory AC commonly until almost 1970, so it might not have been common in Germany into the 1980's. Even today, I understand many vehicles in Europe don't have AC.

gregp1962 · #**433** 06-06-2018, 12:52 PM

This thread looks like it might have all the answers one would need with regard to W123 AC. I have two questions that might be in here but was not able to find them. Can anyone direct me to a post number in this or another thread that might address these two issues?

1) condenser fan not switching on even in hot weather. How do I test and fix this?
2) Is there a way to clean or vacuum off the evaporator without disassembling the car?
1984 300CD, US

ROLLGUY · #**434** 06-06-2018, 09:33 PM

Quote:

Originally Posted by gregp1962

This thread looks like it might have all the answers one would need with regard to W123 AC. I have two questions that might be in here but was not able to find them. Can anyone direct me to a post number in this or another thread that might address these two issues?

1) condenser fan not switching on even in hot weather. How do I test and fix this?
2) Is there a way to clean or vacuum off the evaporator without disassembling the car?
1984 300CD, US

#1- It could be a bad thermal fan switch on the drier, or a bad fuse. Or- I offer a relay that turns on the fan whenever the compressor is engaged. It also gets it's power from the GP relay with an added fuse, so fuse #8 is not overloaded (common problem). This relay will NOT turn on the fan when the engine temp gets high, but that feature is rarely needed in these cars if the cooling system is working properly (in my experience).

gregp1962 · #**435** 06-07-2018, 04:27 PM

Is there a wiring diagram available for the 1984 300CD? specifically for the aux fan control