A/C parts - Page 2 - PeachParts Mercedes-Benz Forum

DocSarvis · #16 07-10-2009, 11:38 PM

I was wondering if it may be volital. Oxygen and grease supposably will ignite. Back to the r22, I realize its legal but is it easier to see or what. I was planning on using pressure and soapy bubbles. Thanks

compress ignite · #17 07-11-2009, 01:30 AM

Use the New Lubricant suitable for your Refrigerant as a flush,while turning
the Compressor by HAND.Until you've gotten all the Old oil out.
(It's Messy And Expensive...BUT Necessary)
ANYTHING else and you're gonna be buying a Compressor.

#18 07-11-2009, 07:06 AM

The dry nitrogen serves to provide lots of pressure while adding an ounce of R22 gives something for the electronic leak detector to find. It's usually not necessary except in the case of really hard to find leaks. If you used dry nitrogen alone it would be safe for the system and you could use soap to look for bubbles.
Doc,

The most common leak detection methods are UV dye, and a black light OR an electronic sniffer. I got by with the dye for awhile, but now good sniffers have come down in price, so I have both.

Unless you get lucky and find the leak with the soap bubbles, there's really no shortcut to leak detection.

Boomer,

If you're agile enough, you might be able to flush the compressor on the car, but it's not that terrible tough to get it off. As apparantly posted earlier, flush the compressor with mineral oil(if you're going back to R12.) Mineral oil is not that terribly expensive.

Break all connections and flush thoroughly both ways and then blow out the hose or component THOROUGHLY with compressed air. Use new o-rings coated with mineral oil or better yet, nylog and reassemble. In the reassembly process put on a new r/d LAST and not until you are ready to evacuate. You will have distributed 8 ounces (I think is the correct amount) of mineral oil with a few ounces in the condensor, a few in the evaporator, a few in the r/d... just distributed around the system. After the r/d is in place and everything is all ready to evacuate, turn the compressor 15 or 20 revolutions by hand to make sure it's not liquid locked with oil.

Evacuate and charge by weight. This is best done with a charging scale, but you can get pretty close with cans and some simple math.

Good luck

leathermang · #19 07-11-2009, 08:11 AM

Quote:

Originally Posted by DocSarvis

Back to the r22, I realize its legal but is it easier to see or what. I was planning on using pressure and soapy bubbles. Thanks

OTHER STUFF is NOT LEGAL to VENT.
That is why I am quoting four ounces of R22 as the TEST MEDIUM propelled by Dry Nitrogen. This is what the EPA specifies for VENTABLE test charge of an electronically detectable type of refrigerant.

I want to see you find a leak on the top of the evaporator using just soapy bubbles. Put it on YouTube and I will forever change my recommendations to people .

leathermang · #20 07-11-2009, 08:16 AM

FLUSH is being used in TWO contexts with regard to AC work.

We should agree to use different terms so people will not get the wrong ideas in their mind's eye.

Flush of the hoses involves flush solvent pushed by a gas like Nitrogen...

" Flush " of the compressor means turning it by hand while adding the proper oil to match the NEW refrigerant that will be used in the car to move the OLD INCOMPATIBLE oil out.

One uses a SOLVENT and pressure.... the hoses ...

and one just uses the new oil poured through by gravity ...the compressor.

bbboomer · #21 07-11-2009, 08:35 AM

Okay guys I thank you all for you help.
I am going to think this over for a day or two.
I need to get an A/C manifold set anyway so I can't really go further at this point.
I have access to R12 and I am really leaning that way.
Thanks again,

DocSarvis · #22 07-11-2009, 09:00 AM

Quote:

Originally Posted by leathermang

OTHER STUFF is NOT LEGAL to VENT.
That is why I am quoting four ounces of R22 as the TEST MEDIUM propelled by Dry Nitrogen. This is what the EPA specifies for VENTABLE test charge of an electronically detectable type of refrigerant.

I want to see you find a leak on the top of the evaporator using just soapy bubbles. Put it on YouTube and I will forever change my recommendations to people .

Thats what I was looking for as far as r22. I realize others are not legal to vent and don't plan to vent them but without a electronical detection device the r22 serves me no purpose. As far as soapy bubbles if I find the leak "good for me" if I don't I put the soapy spray bottle back on my tire rack and move on to the next plan. Sorry I don't play the sucker bet game unless its in person. Thanks

#23 07-11-2009, 02:31 PM

Yes, the soap bubbles will sometimes work, but on most cars you just don't have the visual access. As the cars get newer the visual access becomes more limited.

I did not mention that using an ounce of R22 with nitrogen and then releasing it is acceptable by the EPA. Their thinking is that it's better to release a few ounces of R22 than it is to lose a few pounds of R12 or R134a. BTW, R22 is more detectable with a sniffer than is 12 or 134.

You might get lucky with the soap bubbles, but it wouldn't cost but a few bucks to get an auto a/c to leak check for you. It might very well turn out to be money well spent. Let's just say that you get lucky and find a leak with the soap. Is there any guarantee at that point of this being the ONLY leak?

Good luck with it and keep that R12 thinking going. It is by far your best path.

DocSarvis · #24 07-11-2009, 03:31 PM

Yeah I'm all for getting a sniffer but..... I have to fix at least one ac system with what I have already purchased before I can purchase another 100$ nifty tool. I have to play the cost savings game in my mind. If something is going to cost 200 to get fixed then I can spend 200 on tools and do it myself. Now granted I have 4 cars I wannt to fix but I have to do the first one before I can move on. Thanks

leathermang · #25 07-11-2009, 04:27 PM

DOC, RENT IT !!!
That way you have the smart tool and are using the reliable test method and do not get too much invested in very seldom used tools...
If you do it right your AC system should not need anything for 5-8 years except a small topping off of the refrigerant once during that period of time.

#26 07-11-2009, 06:32 PM

Doc

My thinking regarding tool/equipment purchases is the same, except my purchase calculation uses a different multiplication factor.

This multiplication factor has changed over the years, but even at the age of 60 it allows for more tool dollars than yours.

When I was young I started paying as much as double or even more for tools and equipment to do things with, the thinking that there would surely be another need down the road.

As a result, now that I just turned 60, there's not a whole lot in my shop that I don't have. Even at my age I will spend quite alot. I have to factor in several things:

First of all, by the Grace of God, I have excellent health and I'm in very good physical condition. There's no guarantee in that, I might get run over by a truck or contract a terminal illness before the Sun goes down, but odds are I have another 20 or 30 years in which my stuff has to keep going.

Next, I live seriously in the boondocks, 20 miles from a town of 25,000 and 100 miles from the Dallas/Fort Worth area, so resources are not close by.

Last, I enjoy doing things myself and take great pride in fixing something myself and the satisfying feeling of knowing that it is right.

My $0.02,

bbboomer · #27 07-12-2009, 02:54 PM

Larry,
I'm with you. I am in about the same position, I will turn 62 this year, I don't live in town and I do want what ever tools I get to last as least as long as I do.
I have three cars with A/C but only one that originally used R12. Naturally that is the one with the problem, at least for now.
I don't have all the really necessary tools for inspection, manifold, leak sniffer etc.
I am getting a manifold and I have a vacumn pump but I think the sniffer will likely not happen.
I don't intend to do much A/C work so I will likely not get much more in the way of A/C tools but who knows.
I have always been a do it yourself kind of guy whenever possible, partially because of necessity but mostly just because that is the way I am wired.

leathermang · #28 07-12-2009, 03:54 PM

BBBoomer,
I am sold on the sniffer because my first MB... a wagon ... had a leak in the evaporator... I could have replaced a lot of stuff ( the huge hose across the top of the engine also leaked ) and then found that I lost my R12... this was about 10 years ago when R12 was very high.... and I was not on the internet either...
Is there some way to rent a sniffer through the mail ? or is one on the member's rental list ?

bbboomer · #29 07-16-2009, 04:00 PM

Okay, finally got the gauges and some time to do a little testing. This system is R134 with PAG.
The system equalizes fine. When I put the gauges on it was at about 90 pounds on both sides.
With the engine running at about 1000 rpms the system stabilized at about 270 and 35.
I drove it at about 2000 rpm and 30 mph. The system was running about 260 and 23 but it would fluxuate from about 240 to 275 on the high side and 18 to 25 on the low.
Cooling the condenser with water brought the high side down significantly and immediately but it goes back up as soon as it begins to heat again.
Running the engine at about 1500/2000 with fans blowing on the condenser will not bring the temps or pressure down much. The condenser fan does seem to work as it should.
The vent temps never got below about 58. The sight glass is not clear and looks to be undercharged though the pressures don't seem to indicate that.
Thanks for any input.

#30 07-16-2009, 07:11 PM

I am not familiar with the 126 climate control system, but I suspect that there is something wrong that is either allowing hot coolant through the heater core, or a blend door or outside air door is not operating correctly. Your preliminary analysis of the refrigeration portion sounds as if it should be cooling properly.

Dig into the manner in which the temperature is regulated. My gut is telling me that the 126 uses a monovalve, but I'm just not familiar with the breed.