Leaky AC fitting? - PeachParts Mercedes-Benz Forum

DieselPaul · #1 08-16-2013, 11:25 AM

Has anyone ever had the fitting itself leak on a R134 car?

We had some issues with leaks on my 1992 300D 2.5, used some dye, found leaks at the back of the compressor and in the condenser. Got a new condenser, and a vehicle specific o-ring ring kit. Pulled vacuum on the car, it held vacuum, pulled vacuum on it for like a half hour. Added oil and freon, AC was nice and frosty. Drove the car for 2 hours or so, AC worked great.

Get in the car this morning and the ac won't come on. We put an ounce or two of dye in the car when we filled it just because this car had been problematic and just looking under the hood, dye seems to dripping out of the low side fill port by the glow plug relay.

Had anyone ever had the fitting itself go bad? I will hit the car with the UV light tonight to look for other leaks but there seems to be a ton of dye around the fitting.

Also, does anyone know if like Napa can get R134 fittings? Or are these fittings Mercedes specific? The online EPC seems to only list the whole suction hose not just the fittings.

ROLLGUY · #2 08-16-2013, 11:39 AM

You may just have a bad (or loose) Schrader valve. You should replace the valve anyway, anytime the A/C is serviced.

DieselPaul · #3 08-16-2013, 11:40 AM

This car isn't a conversion, there is no schraeder valve. Its like a little pyramid inside the fitting. I took the high side off thinking the car was an R12 car because I do replace the schraeders and fittings when I service conversion cars. The high side fitting had a big spring in it, and if you look straight into it its the same domed surface, not a schraeder.

This is an original R134a Mercedes fitting

I'll try to take a picture.

compu_85 · #4 08-16-2013, 11:58 AM

One of those fittings leaks on my 99 Jetta. I just leave the cap screwed on tight

-J

ROLLGUY · #5 08-16-2013, 12:21 PM

Quote:

Originally Posted by DieselPaul

This car isn't a conversion, there is no schraeder valve. Its like a little pyramid inside the fitting. I took the high side off thinking the car was an R12 car because I do replace the schraeders and fittings when I service conversion cars. The high side fitting had a big spring in it, and if you look straight into it its the same domed surface, not a schraeder.

This is an original R134a Mercedes fitting

I'll try to take a picture.

If the fitting is part of the hose assembly, and not replaceable, then unfortunately the entire assembly needs to be replaced, or rebuilt. It is possible that you can just replace the fitting by cutting the hose and crimping in a new fitting (provided there is enough hose length). Manufacturers use proprietary fittings to force you to buy the entire hose assembly, and usually at great expense. I am blessed to have the equipment and supplies to make my own hoses, should I ever come across a problem like this on a car I am working on.

DieselPaul · #6 08-16-2013, 02:41 PM

The fitting can be unscrewed from the hose, so worst case maybe I can hope a pick and pull fitting from a lower miled car would seal better. There is an o-ring between the hose and the fitting but this looks like it leaked out of the center of the fitting itself.

DieselPaul · #7 08-16-2013, 03:15 PM

Mercedes sells them 13.50 for 14.10 for the other, they've got one in stock but the catalogue doesn't say which is High and which is Low side, so I'm headed up after I leave the office to see what he's got.

~$15 isn't bad, its much better than $980 for the whole suction hose.