Removing R4 compressor questions - PeachParts Mercedes-Benz Forum

funola · #1 08-12-2016, 01:03 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 · #2 08-12-2016, 01:11 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.

funola · #3 08-13-2016, 10:08 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 · #4 08-13-2016, 10:44 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 · #5 08-13-2016, 11:24 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 · #6 08-13-2016, 11:51 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.

ROLLGUY · #7 08-13-2016, 12:08 PM

Quote:

Originally Posted by funola

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.

Well there you go. That fitting should connected to the manifold, and a male fitting on the other end with a new #12 hose in between looks like it will work for you.
EDIT: you will have to use a 134a charge coupler if using R12.

funola · #8 08-13-2016, 10:49 PM

To flush it, I filled the Harrison R4 that was removed from my 85 300D with 6 oz of mineral oil in addition to whatever PAG oil was in there, which wasn't much when I tried to pour it out, maybe a table spoon came out. Anyway with 6 oz of added oil, it did not hydrolock when I turned the compressor by hand. It just gurgled and spurted out the discharge line.

The other components have all been flushed and dried. I used a mix of carb cleaner and mineral spirit on the condenser and evaporator by cycling it continuously via a solenoid pump. The carb cleaner never touched any AC hoses since it contains some pretty strong solvents not resistant by the hoses, which I believe is Neoprene. To flush the hoses and degrease the condenser and evaporator, I cycled potasium hydroxide through it with the solenoid pump, followed by a few gallons of water, then blowing it out with compressed air, followed by boiling it out with a vacuum pump. We shall see how this works out. I'll have 2 more weeks for it to dry out in this hot weather (I have to order a TXV, dryer and PAO 68 oil) plus I will run the vac pump some more.

The solenoid pump made flushing neat with no mess no spills. This one is doing the evaporator by itself https://www.youtube.com/watch?v=EcP8LJ90mAQ

BillGrissom · #9 08-15-2016, 04:41 PM

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?

Why? I just replaced the short -12 hose on the end of that tube. The tube is lighter than hose, bolts well to the engine, and has the R-12 service port you need. It isn't hard to cut off the collar-crimps. I just used a hacksaw at the end, air cut-off wheel axially, and pried it off w/ screwdriver's and pliers.