valve core replacement UNDER PRESSURE

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valve core replacement UNDER PRESSURE

Postby PredatorOmnivore » Wed Sep 07, 2005 1:33 pm

Short version: #$%&*!!! Defective Brand New Schrader Valve Core

Medium version: The defective valve core is on the high side with the idiot protection mandated 3/16” male flare size service port. I have seen a fancy “Superheat Calculation and Valve Core Replacement Tool” (valve core replacement under pressure), but I assume that it is for HVAC systems and has 1/4” female fitting size. I have a special adapter fitting that fits on the MAC idiot protection mandated 3/16” male flare size high side service port and converts it up to1/4” male flare to fit my standard set of 1/4” hoses. I cannot use this adapter to adapt it to the Tool. My adapter is too long and it does not have a clear path: it has a valve core depressor pin. Does anyone know if this Tool, or some particular brand of this Tool, will reach all the way through some 3/16” to 1/4” adapter to allow me to change the brand new defective valve core? Does anyone know of a particular brand of super short adapter 3/16” female flare to 1/4” male flare?

Verbose version: ***** 45 with one blow ***** I successfully repaired my first MAC. er , a , short of: after running for a while, the system blows 45 F most of time, and on the highway at 60 mph it blows 42 F. I washed off the evaporator in my kitchen sink (removed ¼” mat of dog hair), replaced the TEV, replaced the RD, installed new O-rings in the compressor, installed compressor main seal, flushed with shop air, flushed with mineral spirits, flushed with lacquer thinner, flushed with R-141, put in 4 brand new Schrader valve coress; used a 30 cc syringe to put in the specified amount of oil, re-installed and filled with 50 p.s.i. dry nitrogen and waited overnight. It held pressure just fine, (okay it went down to 47 p.s.i. but I just attributed that to the night time drop in ambient temperature). I vacuumed it out for over an hour. My brand new vacuum pump (hooked directly to my brand new Thermistor Vacuum Gauge) pulled a 20 micron vacuum. When vacuuming via my brand new Manifold Gauge I could only get the vacuum down to 2000 microns although it stayed there for over ½ hour. When vacuuming directly only to the high side using only one hose I got the vacuum down to 200 microns and it stayed there for over ½ hour. (yep, I have a lot of valves and tee’s and hoses). So,… I charged up the system, very slowly (R-12) ; first 12 oz. can with the engine off, then with the engine on (had to hot wire the compressor clutch for a while) then two more 11 oz cans of year 1986 Badger Propel Air Brush Propellant (pure dichlorodifluoromethane). Then Yippee, cold air blowing out of the dash vents and pretty close to book “normal” gauge readings. Then, … I took off the high side hose adapter and #@$$%!!! the brand new valve core was spitting refrigerant and oil. (I know now I should have pressure tested the system with the Manifold Gauge off ; the leaking valve core was hidden by the sealed hoses.) So I put the adapter back on and started cussing. I asked a knowledgeable and experienced HVAC friend of mine and he said he has found many such defective valve cores and on some occasions, when the situation dictated, he just put on a plumbing fitting brass cap with an O-ring and the cap has sealed for years and years with higher R-22 pressures. So, of course this happened to me on Labor Day and no well stocked plumbing stores were open, and all the Auto Parts stores had only plastic caps. I had to wait till Tuesday and I bought 10 brass caps. I got all my tools set up, I installed a nice fitting O-ring, I sprayed the parts with Brake Cleaner, I dried all the parts with dry Nitrogen, I put Nylog on the female cap threads. I was going to also put Nylog on the male threads, but when I took off the adapter fitting; the spraying refrigerant oil mist thwarted that idea. Anyway, the cap sealed the leak so far (no soap bubbles) . I am going to leave it this way, but if the system fails, I want to be able to put on gauges; someday I want to replace that @@#$%!!! Defective brand new valve core. I don’t have a recovery system and recovery tank and I don’t want to give away my R-12 to the AC shop that took my first R-12 for free, but wanted $4/oz to put it back in.
PredatorOmnivore
 
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Postby Duane in Japan » Thu Sep 08, 2005 1:46 pm

There is some kind of scientific name for the fit of those schrader valves, it means that they do not always reseat in the same position twice and may not reseat at all and then by some miricle, reseat just fine.

Your shop that kept your R12 may be allowed to do that according to the EPA, I was reading that they cannot charge you for your old freon BUT they do not have to pay you for your old freon if they do the evacuation for free, your old freon is their payment to help offset the price of their equipment. Again if they didnt charge you for the evacuation. If they kept your freon and charged you then maybe you have a complaint.

I did not see any specific state or local law information because it may be different in every state or county or city, R12 may be illegal in some areas and they may be required to keep it but they should have proof from their local government as a minimum. If they are saying that is the law just from their mouth with no regulation to back it up then they are at fault. They cannot take your R12 just simply because your car has a known leak but they may not be allowed to service a car with a known leak. They should give you all the rules before they take your freon to give you the chance to live with your problem or move to another state as is.
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Postby Duane in Japan » Thu Sep 08, 2005 1:53 pm

Is your air brush propellant not flammable??? Sorry, you got me on the EPA kick here tonight, I dont have to live with the rules where I am so feel free to chat. Is this stuff cheap and non flamable. I am assumming that you put some R12 in to help carry the oil in the system as your propellant may not be compatible with the oil??? Fake R12 (blends) here are rediculously priced, its 98% R134a and its 4 times the price of R134a pure.
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valve core replacement under pressure

Postby PredatorOmnivore » Thu Sep 08, 2005 7:48 pm

I am mostly concerned with replacing the brand new defective valve core. I just screwed in the valve core like I have done forever; just the same as on bicycle tubes and motorcycle tires and car and truck tires. the valve core felt just fine as it was being screwed in. I didn't cross thread it and I didn't feel any burrs or crude n the threads. I did not put a drop of oil on it when I installed it. I think I will change my valve core replacement procedure for the more critical refrigeration cores. I will put a drop of the correct oil on the valve core when I install it. I will test it under pressure with the gauge hoses and the hose depressor pin removed. I jsut need to know how,and how reliably, those fancy HVAC Valve Core Removal Tools work. I have the additional complication of the problem that I am working with a smaller sized service port at 3/16" Male SAE Flare.

I don't care that the AC shop took my original R-12. I was happy for them to recover it for free. I don't have any recovery equiptment. However, I am not going to pay them $4/oz to put any R-12 back in for me. They had a minimum shop bay fee. They promised to give me back, for free, the same weight they recovered from my system, then the extra $4/0z for the remaining charge my AC system specified. They can reclaim it, and recycle it into any other vehicle they want. I just aint paying.

As for the refrigerant I used. I used blow off cans of pure R-12, otherwise known as CFC-12, otherwise known as dichlorodifluoromethane. A long time ago in America it was legal to use R-12 as a propellant for anything that needed a propellant.e.g. aftershave, asthma medicine, paint power spray cans, hair spray, air horn, etc.. I have a huge stash of Igloo brand R-12, and a huge stash of various cans of various products of pure R-12. I only put pure R-12 refrigerant in my AC system. Old, ancient, Badger Air Brush Propellant is pure R-12. The can does not have paint in it. You screw on a leaky "regulator" and run a hose to a tiny spray paint tool, called an air brush, and you pretend you are an artiiist. Or you fill your AC system.
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Postby Duane in Japan » Fri Sep 09, 2005 12:54 pm

forgive my instant ignorance, but your CFC R12 and what everyone else calls Dupont Freon, their patented actual name, they are one in the same??? I remembver way back when in my TV repair days we used some kind of spray ice to freeze the electronic component in question to see if the problem went away and then blame the part for overheating and replace it.

It sounds like you have a gold mine on your hands there Mr Rockafeller, AKA iceman.
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R-12 = CFC-12 = DuPont Freon R-1 = dichlorodifluoromethane

Postby PredatorOmnivore » Fri Sep 09, 2005 11:02 pm

R-12 = CFC-12 = DuPont Freon R-1 = dichlorodifluoromethane

yep, they are all the same. I do not have that big a stash, it is only for personal use without "consideration" (as per some EPA rule)

the electronic freeze spray you used to freeze a suspect component could have been R-12, because R-12 was cheap and lots of companies packaged it into cans and then put on whatever label the seller wanted. The freeze spray could have been any number of other "freons" like R-22 or some mix, you just never know unless the can states "dichlorodifluoromethane". It is always best to check the TP data AND run it through a refrigerant identifier.
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