AC On The Cheap

[Machspeed]

Need to pull a vacuum on my AC system and wondering if one of those cheap HF air vacuum pumps would do the job. Saw a couple of YouTube vids on them and they seem to be alright. Anyone have experience with these? Link below........

https://www.harborfreight.com/air-vacuum-pump-with-r134a-and-r12-connectors-96677.html?_br_psugg_q=vacuum+pump

Also, replacing the receiver dryer/accumulator along with the orifice tube. Old orifice tube is stubborn. Am I correct in that these should just pull straight out?    

[grumpin]

I have one of those. They work fine. I had a 5 HP gas compressor and I felt I was abusing it pulling a vacuum for an hour, and actually cut it to 45 minutes.

I got one of these from HF and I am happy with it. Pulls a vacuum just fine for me.

https://www.harborfreight.com/merchandising-promotions/hot-buys/25-cfm-vacuum-pump-61245.html

[Machspeed]

grumpin wrote

I have one of those. They work fine. I had a 5 HP gas compressor and I felt I was abusing it pulling a vacuum for an hour, and actually cut it to 45 minutes.

I got one of these from HF and I am happy with it. Pulls a vacuum just fine for me.

https://www.harborfreight.com/merchandising-promotions/hot-buys/25-cfm-vacuum-pump-61245.html

Thanks Dane! I know what you mean on abusing the compressor. That is one of my concerns and one of the big reasons I keep going back and forth on it.

I have looked at both the unit you bought and their 2 Stage unit. In fact, printed out a 20% off coupon yesterday, which was the last day it could be used, and was about to head to HF until I realized they were closed.....argh. Found the cheap unit last night and just wanted the input.  

[Gsmblue]

I have the same unit. Works plenty well.

[FuzzFace2]

That's what I used to pull a vacuum on my system, HF vacuum pump.
My son used it on his car when he serviced the AC.
Dave ----

[fr0bert]

I 'borrowed' one from autozone and didn't feel bad leaving it pulling a vacuum for well over an hour.

[FuzzFace2]

OT
Trying to help a friend on an AC system that was working and now is not.

When it was checked the AC charge pressure is low (I do not know what that PSI was) and was told that the system could not be charged because the compressor was bad.

Now how could they tell the compressor was bad with out adding a little to make it work?
If the PSI is to low to kick on the compressor and just for testing, jumped the switch would it show a change between the high & low side on the gauge set?
If it did not show a change between the sides could this be because the charge PSI is that low?

Thanks for any insight
Dave ----

[Gary Lewis]

Dave - You can jump the low pressure switch to force the compressor to run, and you should see the effect on a set of gauges if the compressor is working.  Is that what you mean?

[ratdude747]

I have one as well... Works great. Venturi ones are junk...

[FuzzFace2]

Gary Lewis wrote

Dave - You can jump the low pressure switch to force the compressor to run, and you should see the effect on a set of gauges if the compressor is working.  Is that what you mean?

Yes kind of, I know you can jump the switch to get the compressor to  run but if the system pressure was to low, say 2 or 3 psi, I dont know what psi his system has at this time, could it make the compressor look bad when you jump the switch?

Just trying to figure out why the shop said the compressor is bad and needs to be replaced?
I will be taking my gauge set and vacuum to him on Saturday and may have a little more information then.
Thanks
Dave ----

[grumpin]

If the shop jumpered the switch and ran the A/C, and the gauges showed almost the same pressure, that could indicate a bad compressor.

But, if the pressure was that low, I would find the leak(s), and try servicing it before I replaced the compressor.

I understand why you’re questioning them.

[FuzzFace2]

I talked to my son who has training in refrigeration and he said if the system had little to no psi the compressor would not have anything to pump and could show as being bad.

So till gauges get hooked up to see what the psi is and do a little checking we won't know if it is bad or not.

Will see Saturday after work what we have to work with.
Thanks
Dave. ----

[Machspeed]

Looks like fixing my AC On The Cheap is not gonna be so cheap... 

BTW, a little history.....had the truck converted over to R134A years ago. Inspection after removing parts is that the Accumulator/Filter Drier appears to be OEM to the truck. Also, all the lines have the old black seals. Not sure if orifice tube was replaced. Not happy!

Purchased all the AC lines yesterday because they were the OEM original units and supposedly not compatible with R134A. I'm assuming the replacement hoses are???

Purchased new Accumulator/Filter Drier service kit which included PAG46 oil, seals, valve stems and two orifice tubes. One orifice tube is blue, other looks reddish brown, not sure which to go with. Suspect blue as that is what I've read in other posts on the web and here. Cost $50

Frigg'in old orifice tube will not come out of the evaporator coil, broke the top of it off trying to remove it. Thinking I may have to spring for a new evaporator coil if I can't get the dang thing out of there. Moreover, since new, the truck has always had a slow leak that was traced to under the dash which would likely be the evaporator coil. Every year since purchase had to add a can of R12.  

Was hoping to inspect the orifice tube to get some idea as to the possible condition of my compressor and wondering now if I shouldn't just replace it too?

Thoughts and comments appreciated...............

     

[Gary Lewis]

I'm certainly no A/C expert, and in fact farmed the completion of my system up to my nephew.

But here are my thoughts.

Lines: My limited understanding is that R12 lines that have been in use are compatible with R134a. And that new lines may not be.  I think you may be better off with your used lines, but let the others comment.

Orifice: I'm running a red one in Big Blue and it seems to work quite well.  That's what was in the '90 system and what others recommended, so that's what I went for.  And I think I had to use a screw to get the old one out of my system.

Evaporator: Replace it.  If you had a leak that showed up under the dash then it pretty well has to be the evaporator.  Don't waste your time working on a system that will probably leak.

Compressor: My nephew told me that if the system had been working that the compressor was probably fine.  But since I didn't know if the compressor on Huck had been working I replaced it, which cost ~$200.  I think I'd stay with the existing compressor if I knew the history, as you do.

[grumpin]

I agree, I’m using the original lines with R134.

[Machspeed]

Regarding the lines, I pulled this from the link below and it seems I read this elsewhere as well. My concern too is that flushing the old hose may cause some issues.

https://ricksfreeautorepairadvice.com/convert-auto-r12-system-to-r134a/

On another front, found something weird as I was removing the evaporator coil. This looks like power steering fluid or trans fluid. It's slippery to the touch too. Thoughts on what's going on here?

[Gary Lewis]

I'm now reading the same thing.  Apparently they are saying 1990 was a cutoff/change point.

However, I've read previously that older hoses that have been used will not leak because the oil will have sealed them.  But to be safe, new hoses are a good idea.

[grumpin]

Could that be the oil in the refrigerant that leaked out?

[ratdude747]

Mine was also converted by a PO... but wasn't working when I bought the truck.

Old lines should be compatible.... I reused mine.

If your system has no charge at all, replace the drier.  I cheated and didn't, but mine had a light charge when I got it. All I did was replace the O-rings (and even at that, I apparently missed the one on the front of the condenser behind the grill, whoops!).

The red/brown orifice tube may be a variable orifice tube. I reused my old one (I think), but I have used them on my 1995 Ranger with good success.

Compressor wise, Unless the shaft seal is a leaky oily mess, I wouldn't bother with replacing it. Knock on wood, but the factory compressor in mine has been fine (the FS10's in my two Rangers, not so much; both had shaft seal issues, the first one having a galled shaft that ate seals for breakfast).

[Machspeed]

grumpin wrote

Could that be the oil in the refrigerant that leaked out?

I can't imagine how it would have gotten up there. The refrigerant lines are south of there. Maybe I spilt it out of the drier when I was removing it.

I removed everything yesterday for inspection....evaporator coil, condenser coil, compressor and all the lines. Flushed the condenser coil and will keep it. Looked like the connecting tube on it had a leak and had been leaking for some time. With a new seal, it should be just fine. The evaporator coil was a mess, going to replace it. I also believe it has been a long standing source for leakage. Still on the fence about replacing the lines. I'm a little concerned about the compressor as the hub spins loosely with little suction when rotating by hand. I put my drill on it and felt suction but not knowing any better, not sure it is enough.  

Thanks fellas!