Removing R4 compressor questions - Page 2 - PeachParts Mercedes-Benz Forum

funola · #16 08-11-2016, 11:11 AM

What size and type is the special fitting you need to connect to? Couldn't you replace the metal suction line across the engine with a hose with fittings?

Demothen · #17 08-11-2016, 11:41 AM

Quote:

Originally Posted by funola

What size and type is the special fitting you need to connect to? Couldn't you replace the metal suction line across the engine with a hose with fittings?

I thought about that. I'd need to add a low-side fill port at some point in the system. I talked to the rebuilders and they said that the crimp from the crossover tube to the compressor is the most likely to fail due to the extra strain caused by the sharp angle and thicker hose that curves down to the compressor. They offer a new metal line & hose assembly for that area for a very reasonable price, and I'm at the point where I really just don't want any more work to do - so I am going to order that. I'm also going to be cutting the TXV side crimp and end off and having a new slip-over fitting brazed on over it. Fortunately a member of my family is experienced in brazing high pressure systems, so I'll bring him the assembly when I'm in town shortly.

BillGrissom · #18 08-11-2016, 05:30 PM

Quote:

Originally Posted by funola

What size and type is the special fitting you need to connect to? Couldn't you replace the metal suction line across the engine with a hose with fittings?

Re-read my post #9. Re-use the outer fittings, just add new hose.

If you do want to procure new fittings, it will take detective work. I think they are an O-ring fitting w/ metric nut and perhaps not even the same tube size as SAE O-ring fittings. That is why Rollguy decided to just braze an old M-B fitting to form his custom hose assemblies. Don't assume that Europe was standardized on fittings in the 1980's. A Wheeler Dealer's episode explored that when trying to source a hose for an Italian sports car in England. They said Lamborghini (?) used an unpredictable mix of various fittings. Ditto for other rare fittings on your M-B.

funola · #19 08-11-2016, 07:03 PM

Quote:

Originally Posted by BillGrissom

Re-read my post #9. Re-use the outer fittings, just add new hose.

If you do want to procure new fittings, it will take detective work. I think they are an O-ring fitting w/ metric nut and perhaps not even the same tube size as SAE O-ring fittings. That is why Rollguy decided to just braze an old M-B fitting to form his custom hose assemblies. Don't assume that Europe was standardized on fittings in the 1980's. A Wheeler Dealer's episode explored that when trying to source a hose for an Italian sports car in England. They said Lamborghini (?) used an unpredictable mix of various fittings. Ditto for other rare fittings on your M-B.

Do you know what the core of the OE Mercedes hoses are made from? Just want to make sure I use compatible flushing agent on them. For now I plan on re-using all hoses if they pressure test good. I have 2 more hoses to do. So far I have found no leaks, including the compressor, which I had under water and no bubbles!. The first time I tested the compressor was still in the car. I did a input suction and output pressure test by hooking gauges to the inlet and outlet and cranking the engine. I got good vacuum and pressure. I did a pressure and vacuum test with the digital test set and it held vacuum but leaked badly with pressure. I think it may be due to the sad shape of the o-ring on the high side fitting by the alternator (see pic below). There are other o-rings in similar condition. If everything pressure test good, I will just install new o-rings and charge it with R12 and PAO 68 and see how it works out. If it fails, I'll consider barrier hoses then.

ROLLGUY · #20 08-12-2016, 12:48 AM

I will try to reply tomorrow with some photos, showing the different fittings.

Demothen · #21 08-12-2016, 09:45 AM

Funola,
That high side hose by the alternator was in bad shape on my car, I think due to a leaky oil cap/oil breather. You might try to dig your fingers into it and make sure it's solid. If you need a new one, I think I'll have one that won't be getting used now that I'm switching to a Sanden. I could sell it to you cheap if you want it.

funola · #22 08-12-2016, 09:56 AM

My hose looks ok and passed the underwater and digital pressure gauge test. I even cut away the thick heat shrink layer so I can see bubbles more readily... there were none. Here's a video of the test https://www.youtube.com/watch?v=SsROH43eLxg

PM me the price of the hose. I may consider it if the price is right.

ROLLGUY · #23 08-12-2016, 11:11 AM

Here are some photos of beadlock fittings and one of a factory MB sleeve cut and ground off.
The first photo shows the sleeve mostly cut off to show how it is captured by the "bead" (groove). Without the sleeve being part of the fitting, the hose and crimped sleeve would come off under pressure because of the almost non-existent barbs.

Photo 2 shows the fitting without the sleeve

Photo 3 shows a weld-on barb brazed to a fitting

Photo 4 shows an MB pipe with the sleeve ground off, and a fitting welded on. If a hose was crimped on the end after the factory hose and sleeve were removed, the hose and sleeve would come off under pressure.

I don't suggest using factory barbs to attach new hoses to. A barb made for that purpose should be welded on so standard hose and sleeves can be used. These have more aggressive barbs on them to hold the hose, without needing the sleeve to be a part of the fitting.

funola · #24 08-12-2016, 12:03 PM

Quote:

Originally Posted by ROLLGUY

Here are some photos of beadlock fittings and one of a factory MB sleeve cut and ground off.
The first photo shows the sleeve mostly cut off to show how it is captured by the "bead" (groove). Without the sleeve being part of the fitting, the hose and crimped sleeve would come off under pressure because of the almost non-existent barbs.

Photo 2 shows the fitting without the sleeve

Photo 3 shows a weld-on barb brazed to a fitting

Photo 4 shows an MB pipe with the sleeve ground off, and a fitting welded on. If a hose was crimped on the end after the factory hose and sleeve were removed, the hose and sleeve would come off under pressure.

I don't suggest using factory barbs to attach new hoses to. A barb made for that purpose should be welded on so standard hose and sleeves can be used. These have more aggressive barbs on them to hold the hose, without needing the sleeve to be a part of the fitting.

Questions:

1. Photo 3 does not have a beadlock type ferrule. Why didn't you use a weld-on beadlock type?

2. In photo 4, what kind of fitting was welded on to the pipe? What kind of pipe is that and why was that work necessary?

ROLLGUY · #25 08-12-2016, 12:11 PM

Quote:

Originally Posted by funola

Questions:

1. Photo 3 does not have a beadlock type ferrule. Why didn't you use a weld-on beadlock type?

2. In photo 4, what kind of fitting was welded on to the pipe? What kind of pipe is that and why was that work necessary?

The fitting in photo 3 is a custom fitting that has a #8 barb brazed to a #10 fitting (used in my Sanden hose kits).
The fitting welded on the pipe is done on all the 123 Sanden retrofits, so a hose can be connected from that pipe (low side hard pipe going on top of a 616 or 617 in a 123) to the compressor. Check out the PDF installation guide link in my signature.

BillGrissom · #26 08-12-2016, 07:25 PM

The high-pressure hose in one of my 300D appeared to have 2 layers, since the outer layer was spongy and delaminating at the compressor, probably what you termed "heat shrink". It appeared the inner part was just rubber, w/o a dense plastic liner as in "barrier" hose. Similar SAE fittings w/ integral ferrule are termed "Coll-O-crimp" (brand?). I think just a convenience, not to give superior clamping, though probably helps. I am not concerned w/ the hoses slipping off the M-B fittings (OK several years now). Millions of cars in the 60-70's had dealer or after-market AC installed, w/ similar barbed fittings and just a screw hose clamp (special AC ones w/ locating finger). My 65 Newport was like that and I had to cut the hose and aggressively peel it off the barb when I replaced them.

Before tossing your old hoses, cut off the metal ends and save, since those are special, and won't take much space in your garage. You or another guy here will likely need one in the future.

Re other M-B hoses. I recall that on some I rebuilt, their crimped ferrule had depressions that aligned with the ripples on the hose insert. Those had long ripples, not the many little barbs shown in post 23. I re-worked all AC and oil cooler hoses, so forget which. Anyway, I was able to align the crimps in my Master-Cool crimper to match close enough. Your high-pressure power steering hose can be replaced using just box wrenches. It uses "field-replaceable" fittings that screw on the hose. Be glad because I see ~$80 ea prices for those (Parker catalog?). If you can't find my post w/ photos, the trick is that the outer piece is a left-hand thread, so turn it "righty loosy" to unscrew from the hose OD. It is a large "light-bulb" thread. Same fittings on the SLS hoses (300TD guys, their posts informed me). Do buy high-pressure "2-wire" hydraulic hose for that (3000 psi rated, ebay, Tractor Supply), which is superior to what M-B used.

funola · #27 08-13-2016, 09:08 AM

Quote:

Originally Posted by ROLLGUY

.......
The fitting welded on the pipe is done on all the 123 Sanden retrofits, so a hose can be connected from that pipe (low side hard pipe going on top of a 616 or 617 in a 123) to the compressor. Check out the PDF installation guide link in my signature.

Why can't that low side pipe be eliminated with a -12 hose and -12 fittings with a service port to go between the R4 compressor manifold pipe and the suction hose from the TXV?

Demothen · #28 08-13-2016, 09:44 AM

Quote:

Originally Posted by funola

Why can't that low side pipe be eliminated with a -12 hose and -12 fittings with a service port to go between the R4 compressor manifold pipe and the suction hose from the TXV?

I havent tried, but it is real tight routing where it dips under the cruise control and behind the power steering pump. Just to get the pipe out I had to pull the cruise control and disconnect the vacuum pump.
Fun tip: the vacuum pump can be capped using a clean port cap for a receiver drier, if you have out laying around. I have taken to saving all of the caps I get with various fittings, they seem to work in other fittings somewhat frequently.

ROLLGUY · #29 08-13-2016, 10:24 AM

Quote:

Originally Posted by funola

Why can't that low side pipe be eliminated with a -12 hose and -12 fittings with a service port to go between the R4 compressor manifold pipe and the suction hose from the TXV?

I doubt an inline service port is available in #12, but if so, I can't see any reason why the pipe couldn't be eliminated, and use rubber hose all the way for R4 installations.

funola · #30 08-13-2016, 10:51 AM

Quote:

Originally Posted by ROLLGUY

I doubt an inline service port is available in #12, but if so, I can't see any reason why the pipe couldn't be eliminated, and use rubber hose all the way for R4 installations.

Here's one

http://www.ebay.com/itm/261566328165 with #12 fitting, however it does not specify #12 hose so assume it is. Not sure what a 13 mm service port is. I need 1/4 SAE service port since I'll be using R12..

This is if using my old hoses which all tested good do not work out and I still have a slow leak, then I'll make my own barrier hoses and re-route them. I am betting on re-newing all o-rings and schrader valves will fix my slow leak.