Crushing AC development..... - PeachParts Mercedes-Benz Forum

JimmyL · #1 06-10-2006, 02:35 PM

Went to get in the wagon this morning to run to Harbor Freight, with the memories of 45 degree vent temps from the night before.
Start car, hit my AC button ready to hear the rpm drop......nothing. Not good.
Went and removed the two wires from pressure switch and connected them to my jumper, compressors comes on. Uh oh!!! Surely not!
Pull wagon into garage and connect guages with car off. Only 35lb of pressure.
Freon mostly gone!
I held 29" vac for 18 hours, and felt good. But the pressure found a weak spot. (Insert senseless yet calming cussing tirade here)
Crawl under car, and yes folks, all kinds of oil around those M****** questionable compressor seals from a previous thread. Fastlane, you read these?

Don't even have the life force to type anymore..........

#2 06-10-2006, 02:36 PM

Sometimes vacuum can pull closed holes that are open under pressure.

jbaj007 · #3 06-10-2006, 02:54 PM

Quote:

Vehicle 1985 Mercedes Benz 300TD Turbo Wagon
Part: A/C Compressor

Note: GM radial R-4 version
Compressors having stepped ports require the the following seals be installed in the following manner : The large brass seal is only for the suction port. The green seal is to be used on the discharge port. The short(er) of the two sleeves is to be used in conjunction with the green seal. This centers the seal, which is essential to prevent leakage. The two other seals in the kit are not applicable for Mercedes. These seals will only be used in compressors having a stepped port configuration. See 24 342

There should be two aluminum sleeves with your seal kit. The SHORTER sleeve goes in the GREEN seal in the left (in your picture) stepped port. NO sleeve in the right hand port. W/o the sleeve they leak; with it, they still leak sometimes.

Best of luck and I hope it works out well.

tangofox007 · #4 06-10-2006, 04:08 PM

Quote:

Originally Posted by jbaj007

There should be two aluminum sleeves with your seal kit. The SHORTER sleeve goes in the GREEN seal in the left (in your picture) stepped port. NO sleeve in the right hand port.

Exactly how is the aluminum sleeve installed? The instructions say to press the insert into the manifold. My manifold already has a "lip" on the discharge side.

JimmyL · #5 06-10-2006, 05:21 PM

Quote:

Originally Posted by jbaj007

There should be two aluminum sleeves with your seal kit. The SHORTER sleeve goes in the GREEN seal in the left (in your picture) stepped port. NO sleeve in the right hand port. W/o the sleeve they leak; with it, they still leak sometimes.

Best of luck and I hope it works out well.

OK, back from my cooling off period. (which was in a simple Ford truck with freezing AC)
So I need to install the alum. sleeve on the left in my pics below of leftover parts? Will I need to get new seals now since these have been torqued, possible incorrectly? And which way does that spacer go? Lip in, lip out?
And sometimes it still leaks??

leathermang · #6 06-10-2006, 05:27 PM

How much do the replacements for the crushed seals cost ?
How much does the refrigerant cost that will be lost if you don't get it sealed this time ?
How much driving will it save if you go ahead and buy TWO new replacements of everything you need in case you need them tomorrow when everything is closed ?
LOL

jbaj007 · #7 06-10-2006, 07:53 PM

JimmyL,
I think it will go in only one way and still have a decent fit to the green washer. Lip in, i think from memory (such as it is). Left (shorter) sleeve is correct.

Washers are probably still good. Wouldn't hurt if spares were available as Greg suggests, though.

tangofox007 · #8 06-10-2006, 08:20 PM

Quote:

Originally Posted by jbaj007

JimmyL,
I think it will go in only one way and still have a decent fit to the green washer. Lip in, i think from memory (such as it is). Left (shorter) sleeve is correct.

Mine won't fit either way. The discharge side of the manifold already has a lip or shoulder that is going to penetrate into the ID of the seal when the seal is installed.
The insert would make sense if both sides of the manifold were flat, like the suction side.

tangofox007 · #9 06-10-2006, 08:22 PM

Quote:

Originally Posted by JimmyL

Will I need to get new seals now since these have been torqued, possible incorrectly?

How much torque did you use? My compressor instructions say 25 ft/lbs.

JimmyL · #10 06-10-2006, 09:10 PM

Quote:

Originally Posted by tangofox007

How much torque did you use? My compressor instructions say 25 ft/lbs.

I was not that exact, to tell the truth...
Sounds like you had better instructions with yours than I did.

JimmyL · #11 06-10-2006, 09:20 PM

Quote:

Originally Posted by leathermang

How much do the replacements for the crushed seals cost ?
How much does the refrigerant cost that will be lost if you don't get it sealed this time ?
How much driving will it save if you go ahead and buy TWO new replacements of everything you need in case you need them tomorrow when everything is closed ?
LOL

Grasshoppa make 3 good points......

Quote:

Originally Posted by jbaj007

JimmyL,
I think it will go in only one way and still have a decent fit to the green washer. Lip in, i think from memory (such as it is). Left (shorter) sleeve is correct.

Napa will be open tomorrow I believe. Now I have the quandary of how much oil did I loose? Is an ounce or two likely, or less?
At least I'm glad under current circumstances that I went the Freeze12 route. You know how sick I woulda been had I vented precious R12

Is there a way to pressurize the system w/out buying one of those 30 gal nitrogen cannisters? Do you need a license for one of those, and, how much are they?

**Also, whenever I'm really down, like now for instance, I walk outside, start the wagon, stand behind it, and admire the lack of smoke. It could be worse!

leathermang · #12 06-10-2006, 10:52 PM

You do not need a license for the Nitrogen tank....
I think mine was $150 new, filled.
I have not bought a regulator for mine yet... so far it is looking like I can use the one off my Argon bottle... but I don't know that it would do for flushing...

tangofox007 · #13 06-11-2006, 08:52 AM

Quote:

Originally Posted by jbaj007

I think it will go in only one way and still have a decent fit to the green washer. Lip in, i think from memory (such as it is). Left (shorter) sleeve is correct.

My manifold already has a short pilot tube on the discharge side. The ID of the tube is 0.1" smaller than the OD of the insert. Does the existing tube need to be enlarged to make the insert fit?

tangofox007 · #14 06-12-2006, 10:04 AM

JimmyL,
I am anxiously awaiting some news on your project. Is there any chance that you did not have the manifold tight enough? Any obvious reason that it leaked?
I just bolted my new, stepped-port compressor on. Could not see how the pilot inserts were going to fit, so I installed the seals by themselves. Currently at a stand-still awaiting delivery of a new vacuum pump.

leathermang · #15 06-12-2006, 10:16 AM

I assume you guys are using Nylog on these seals ?

JimmyL · #16 06-12-2006, 10:17 AM

Quote:

Originally Posted by tangofox007

JimmyL,
I am anxiously awaiting some news on your project. Is there any chance that you did not have the manifold tight enough? Any obvious reason that it leaked?
I just bolted my new, stepped-port compressor on. Could not see how the pilot inserts were going to fit, so I installed the seals by themselves. Currently at a stand-still awaiting delivery of a new vacuum pump.

There is no chance that it wasn't tight enough. For sure. I was not able to use a torque wrench, as only a wrench would fit, not a socket. I did use Nylog, BTW.
I'm heading back to work this week, so it is going to be much harder to research. I've got 6 pictures printed out and in my shirt pocket, but I'm not sure where to go to even ask.
If you would like to take the lead on this, I will gladly follow.....

Off to work I go.

Pete Burton · #17 06-12-2006, 10:45 AM

ZZZZZZZZZZZZZZZZip!! OK, now that I have my flame suit on, I'm going to suggest something. Consider pressure/operation testing your system with R290 - propane. I'll readily admit to having done this recently. I do not have a tank of dry nitrogen otherwise I would have used that. However, my situation was this: Original system except for reman Four Seasons compressor and R/D I installed in 97. Worked until I parked the car awaiting an engine rebuild after it wouldn't start reliably in the winter (about 4 years ago) Rebuilt the engine, replaced oil in compressor with fresh. Evacuated and charged system with propane. Ran system for about 3 minutes in driveway verifying general system operation. I got it to put out noticably cool air at the vents and sweat on the suction line. Propane doesn't carry the oil around much, so I didn't want to do it for any longer. Put gages on and let the car sit in the driveway over the weekend. System pressure went down and up with ambient temp, but did not appear to leak. Then, I replaced R/D with a new one (and about 60cc's of oil), evacuated and charged with R12.

Works very well with the exception of my ETR switch, which I've known is cutting out compressor at 8C instead of 3C. I even recovered the R12 from the dehumidifier that I got at the dump which I made my vacuum pump with.

tangofox007 · #18 06-12-2006, 10:50 AM

Quote:

Originally Posted by leathermang

I assume you guys are using Nylog on these seals ?

I am using Nylog on the hose fitting o-rings and schrader valves. But the instructions that came with my Four Seasons compressor cautioned that the compressor-to-manifold seal washers were to be installed dry. Quote: "DO NOT lubricate washers. Install dry."

leathermang · #19 06-12-2006, 11:08 AM

How appropriate !!! A FLAME suit when using PROPANE !!!
LOL

leathermang · #20 06-12-2006, 11:13 AM

"compressor-to-manifold seal washers were to be installed dry. Quote: "DO NOT lubricate washers. Install dry."

Wow, I wonder why. Nice to see someone that reads the installation instructions before installing !!