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Discussion Starter #1
I have a 96 f-250. One of the lines for the A/C rotted away, and freon/oil started to leak out. The lines still have presure inside them, but not enough to blow cold air.

I bought an entire new line, that has the low/high side valves installed.

Everything worked fine, until the line started to leak. Maybe a half of a teaspoon of oil leaked out.

How do I change this hose ?

I know I have to drain out the freon from the system.

Do I have to ADD any PAG 46 oil to the system when adding new r-134 ? If so, where does it go into, I have PAG 46 oil that gets POURED in from a bottle

When vacuuming out the moisture from the system, does it go on the low side or high side port ?
 

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I'm confused as to which line your changing, some just have a threaded fitting and one off the dryer has a spring compressed fitting that you need a special tool for ( fuel line disconnect tool works) and you might not be able to pour the oil in after its put under vacuum, you need a gun with a low side connection fitting/coupler so it can be put in after youve sucked it down and i think it needs 9 ounces of oil. hope this helps:beer
 

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Same here, which line is leaking? Does it look like this one?


The only way to know for sure how much oil to add is to dump out what is in the compressor and receiver/drier into a measuring cup. Typical oil charge is around 7-9 ounces IIRC. If it has not been leaking too long I would just replace what I thought has leaked out.

Here is an evacuation procedure from my service CD:

Evacuating the System

1. Discharge refrigerant system as outlined.

2. Be certain that the manifold gauge set is connected as follows:

a. Low pressure hose connected to low pressure service gauge port on top center of the accumulator/drier assembly.

b. High pressure hose to high pressure gauge port on compressor discharge line at condenser connection. An adapter is necessary at this service gauge port.

c. Connect manifold gauge set center hose to a vacuum pump.

3. Open manifold gauge set valves and start vacuum pump.

4. Evacuate system with vacuum pump until low pressure gauge reads at least 84 kPa (25 in. Hg) (vacuum) and as close to 101 kPa (30 in. Hg) as possible. Continue vacuum pump operation for 15 minutes. If part of system has been replaced, continue vacuum pump operation for an additional 20-30 minutes.

5. When evacuation of system is complete, close manifold gauge set valves and turn vacuum pump off.

6. Observe low side gauge to make sure system holds vacuum for five minutes. If vacuum is held for five minutes, proceed to charging the system. If vacuum is not held for five minutes, leak test system, repair leak(s) and again evacuate system.
 

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Discussion Starter #4
That picture is the exact same hose I'm replacing....Its rotted about 2" from the high pressure Schrader valve.

I just want to add the new line and add some oil.

It looks like I lost maybe 1-3 teaspoons of oil.

Couple of questions.....

When I take out the old hose, will I loose more oil, or will the oil settle to the lowest points in the system ?

Where do I put the NEW OIL in, I want to add maybe 2-3 teaspoons when putting in the new hose.

After putting in New oil, and the new hose, I will then vacuum the system....Will the vaccum pull out any of the oil from the system ?

THANKYOU for the procedure you outlined above....!!!!
 

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If it were mine I would replace the amount of oil that looks like leaked out. When you remove the hose, you may lose a little more, but most likely you should be okay. To add more oil attach the hose assembly to the compressor, pour in the desired amount into one end of the hose then attach. You might also try spinning the compressor by hand to help distribute the oil in the compressor.

Your vacuum should not remove any oil. Since you did have a leak you might consider a new receiver/drier, but it all depends how much charge is left in the system. IF you still have pressure, I would not worry too much about it.
 

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Discussion Starter #6
Thankyou for your help....:beer

The leak just started , the high/low lines still have plenty of pressure in them, just not enough to cool the truck off. I will change out the hose, and add just alittle oil, plus the freon. I think the drier should be fine....

Thanks again for the help with the questions I had....ps where did you get the service CD you have ?
 

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I found it online quite some time ago. Ebay and a few other places have them available for a reasonable price most of the time or you can go the Helms and purchase a real copy.
 

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Discussion Starter #8
Seems to be working good so far..

I pulled a vacuum on the system, and added 38oz of freon, and 1oz of oil.

The system is blowing cold air..

How much R-134 should I put into the system ?

I used a good manifold gauge set, and I had about 32-35 lbs. on the low side, and about 205-210 lbs.on the high side. It was between 85-90'f outside , and the truck had the windows closed, and it was ice cold inside.

Should the high side line (near the test port) be HOT to the touch ?

All other lines are cold.

Should the compressor be turning on/off at idle, the compress is staying engaged at idle ? (I'm not sure if its supposed to cycle on and off,or stay on continous at idle speed, with A/c switch on MAX)

Everything seems to be working, I just wanted to check some of the above questions.
 

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You needed only 33 oz. for a full charge of R-134a. Now you are overcharged. Depending on the ambient temperature/humidity as well as cabin temperature the compressor may not cycle on/off. Yes the high side line does get hot during normal operation. Your pressures are a little high on the low side more than likely due to the overcharge.
 

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Discussion Starter #10
You needed only 33 oz. for a full charge of R-134a. Now you are overcharged. Depending on the ambient temperature/humidity as well as cabin temperature the compressor may not cycle on/off. Yes the high side line does get hot during normal operation. Your pressures are a little high on the low side more than likely due to the overcharge.
I didn't realize it was overcharged....I was using 2 cheap gauges that came with the refill kit....they both showed I should add more freon according to the temp on the gauge, plus it wasn't blowing cold. After the 3rd can , it started to get cold. I even tried another cheap gauge for just checking the Pressure on the low side, and even that gauge still said I should put even more freon in. But I figured 3 cans were enough.

Then I put the good gauges on, and it showed about 32 PSI on the low side. And 205 PSI on the high side.

What should the gauges read on the LOW side , and High side with the engine running, and A/C on MAX ?????


Should I let some R-134 out ?

Is it bad to be overcharged ?
 

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MAX FAN/MAX COOL on a 90degree ambient, the pressures are ok.

Whats the temp like where you are?
 

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Discussion Starter #12
Temps are between 85-90'f, hot/HUMID....I'm going to see what the PSI is like on Saturday..supposed to be 100+f here....:barf
 

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Yes it is bad to be overcharged. 38 oz. is too much. Run the engine at 1500-1800 RPM for 10 minutes, watch the high side pressure, if you go above 350+ that is bad IMHO. The resident asian has plenty of experience, but good quality gauges will tell the true story.
 

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Discussion Starter #14
Well it reached 98'f here today.

I retested the system with 2 other professional manifoild gauge sets.

Both gauge sets measured 38-40 psi on the low side , and 290 psi on the high side, with the A/C on MAX with windows closed.

When I put the A/C on just regular cool, the pressure goes up to 65 psi on the low side, and between 375-400 psi on the high side.

So I drained out alittle freon, and now it won't cool at all.

The pressure after draining out alittle freon, went down to 28-32 psi on the low side.

Seems like my A/C will not produce cold air , unless there is between
36-38 oz. of freon in the system . No cold air is coming out with 30-34oz of freon.

Autozone and Advanced Auto shows 37oz as the required amount of freon to be added to the A/C.

I guess I will just run it with 37 oz in the system. 38 oz produced some nice cold air.
 

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Dude, the pressures were just fine where you had left it.

You guys aren't accounting for the amount of refrigerant in the gauges/hoses when he charges.

Check your fan clutch and condensor for debris your high side was climbing a little higher than i like.

I just checked alldatapro (one of the repair guides at the shop i use, it shows 38oz for a 96 F250 w/351 FS10 compressor)

With it being 90-95 degree out at idle, max fan max cool you should be at 38-40/250-275.
 

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Discussion Starter #17
I was concerned with the high side readings also, thats why I drained alittle out.


How should I check the fan clutch or condensor for debris ?

Is it something external to look for , or something internal ?

When I replaced the hose, the FLARE Fitting on the high side was alittle distorted when I purchased the hose, not perfectly round, but I was able to pretty much bend the flare back to a rounded shape.

Maybe the o-ring got pinched inside the flare when attaching it to the radiator, and a piece of the o-ring is inside the hose ?

Maybe thats causing the high reading ?

If the o-ring got pinched, wouldn't it leak from the high side fitting ? I am not loosing any freon....

Or could it be I possibly added to much oil to the system...I didn't check the levels...I added about 2oz of PAG46. It didn't seem like I lost alot of oil from the rotted area on the old hose, so I just added what I thought may have leaked out. Maybe thats causing the higher readings ?

WHAT SHOULD BE THE PRESSURE READINGS BE AT 90-95'f, WITH THE A/C on REGULAR (Not MAX) ?
 

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don't attempt to check the a/c when its not on max. thats because you will be pulling in hotter outside air which will throw your p/t off. (pressure/temperature)

I replyed to someone else's pm earlier. Look around the front and back of the fan clutch for any signs of the viscous fluid leaking. you will see dirt accumulated if its leaking. With the truck running and warmed up (a/c running) the fan should be moving a good amount of air. Take a rag and slowly drag it into the fan and see if it slows down. It shouldnt. The fan should be turning about the same speed as the pullies at idle. Rev it up to 12-1300rpm and it should increase with speed. Make sure the condenser is clean and the rubber seals that are around the grille and condenser. A pinched oring will not cause what you see. It would leak if anything.

You can check it cold too. It shouldn't free wheel more than twice when cold. Also when you start it when its cold you should hear the fan clutch engage for a few seconds. Let it warm up to operating temp and spin again. If its easy to spin its bad. If you don't or are in doubt replace it. A fan clutch can get weak over time, as much as loosing 15 rpm per year.

and when i say check the condeser for debris. Make sure the fins are clean both infront and between that and the radiator.

DO NOT BUY CHINESE FAN CLUTCHES. I installed a few from Bennett and autozone. Every single one i installed had to be removed and replaced with a quality unit. The imperial ones from Advance are good, so are the ones from napa and of course OEM ford.
 

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Discussion Starter #19
I'm pretty sure the fan clutch is ok, I don't remember seeing any fluid or build up around it, and the condensor is clean around the outside.

I kept checking the pressure readings between MAX and normal.

Whats probably happening is, it is sucking in the hotter air, and throwing the gauges off. I never reset the presure readings, when switching between MAX and Normal. So the gauges probably spiked alot when switching between settings.

I will drain the system down again tomorrow, vacuum it down, and put new freon back in. It was within specs the first time after refillling, but I kept testing the pressure readings and was worrying about it, and I probably threw the readings off on the gauges when switching between MAX and NORMAL.

I didn't realize I should only test the A/C on MAX....:duh:doh0715::twak

I will give it another try in the morning...


THANKYOU VERY MUCH FOR YOUR HELP.......!!!!!!!:beer
 

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You won't do a thing to the gauges switching between max and norm a/c. the gauges do show actual system pressure as the system is operating.

Evac + recharge is a good idea. Thats what i would do.

Take a flashlight and inspect your fan clutch especially around the front of it where the bimetal coil is and around the rear shaft seal. Your high side is a little high.

It'll take but a minute to check, don't brush it off unless you are sure otherwise you might end up with a junk FS10 and a contaminated system.These compressors don;t like high head pressure.
 
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