AC high/low side?

[euclid]

Converting the AC on my buddies 84 FJ60 to 134A. I am pretty sure the inside (closer to the engine) is the High (Red) AC port and the oustide (closer to fender) is the Low (blue). Can someone confirm or correct this? A picture would be nice so I know I'm not screwing it up.

Unfortunatly, the old AC ports were the same size, so it is possible to screw this up pretty bad. Hopefully my trial and error last night didn't secrew it up too bad.

TIA

 

[rightlane]

mine shows red toward the bumper, blue toward the block

 

[euclid]

Blue closer to the block.. red farther from the block. Anyone else that can confirm? Not that I doubt you rightlane.. ;p Thanks for the reply

 

[euclid]

AC retrofit - did I screw up?

So here is where I am: We got a new set of retrofit fittings that work better than the origionals. Removed the valve cores from both high and low side and installed the fittings per the reasoning above, red toward the bumper, blue toward the block.

When I preasure up the blue side with new freon I get nothing. The guage runs up to 90, and no freon flows from the bottle. No blockage in the guage, checked that.

Only idea I have so far is that I may have preasureized the high side last night by installing the retrofit valves on the wrong sides. My theory is that the expansion valve may be toast from having preasure on it from the high side.

Any ideas? Don't know what to do next.

 

[kevinmrowland]

Hey Greg,
I can't remember which is where, but........... If you clean the grime off the compressor casting there will be an "S" and a "D" on it, Suction Discharge, Low and High, accordingly.
Does that help any?
The High hose is small and the Low hose is big, does that help any?
Thats all I got,
Kevin R.

 

[BigGun J]

First off you need to evacuate the system "of course it had no freon that you let into the atmosphere" and then draw a vacuum on it. You need to run a vacuum pump on the system until it will hold 300 microns minimum. If you do not, and allow "air and non-condensables" into the system it will not work very well. The compressor sucks and pushes. LOW side is from evaporator to compressor and HI side is out of compressor to condenser in front of radiator then back to evaporator. General rule of thumb after vacuum has been achieved is charge liquid into the HI side. "Jumper LOW side pressure switch," start the vehical, then slowly charge vapor through the LOW side. Do not charge liquid into the LOW side or you will be replacing the compressor. It's called slugging the compressor. It would be a good idea to replace the filter/dryer as well. Good luck.

Jim

 

[euclid]

Very helpfull. We will try it again tonight.

Any ideas on why the system wouldn't take any freon?

 

[thetaxmonkey]

once you have evac'd the system, make sure your compressor is running - i.e. the clutch portion on the front of it is turning in sync with the belt pulley. If the front is not spinning your compressor is not on. This could be the pressure switch or usually has to do with the rpm knob down to the left under the glove box (allows you to adjust the point in the engine idle rpm's at which your compressor turns on or off - for instance - if set at 800rpm's, when you are driving down the road the compressor is running, if stopped at a stoplight and idling at 700, compressor clutch is disengaged until you go again and rpm's reach at least 800)

p.s. there will be a larger hose coming off of the low pressure side and the high pressure will have a smaller one.

hope some of this helps

 

[euclid]

That is helpful. A quick follow up question. It was my understanding that the compressor would be damaged if run without freon, and that there is a low pressure switch to keep the compressor from turning on untill the freon is high enough. In the past I have been able to charge systems up without the compressor running, then it charges quicker with the compressor running. This is all based on having vacumed the system down first.

Am I midssing something? Why won't this thing take freon? Any ideas on wether or not I could have damaged part of the system, like the expansion valve?

 

[euclid]

Wow, still no luck. How do you jump the LOW side pressure switch? I want to jump it so that the compressor will come on and see if that makes it take freon.

 

[thetaxmonkey]

if the system is vac'd, you should be able to put enough freon in without it running, maybe even enough to get the switch going which if I remember correctly is 14lbs psi. if you want to get the thing running enough to get it to take freon, make sure rpm knob is all the way down and your idle is up enough. If this doesn't do it, the easiest thing to do with engine idling and ac on, run a jumper from disconnected black power wire straight to 12+ on battery. This may allow you to get enough pressure in the system to satisfy the switch. I believe the switch is located under the dash in evaporator assmbly and is a PITA to remove. Your expansion valve is also in here.

 

[euclid]

taxmonkey,
Very helpfull stuff you have posted...thanks.

I have tried everything you suggested with no luck. I tried the rpm nob turned all the way in both directions, with the truck idled up to about 1K rpm. I put 12V to the black wire running to the compressor, no luck.

A test light on the black wire shows no voltage with the AC button on or off.

AC fuse is good.

Yeah, best I could figgure from the book the preassure switch is up under the dash. I was confused if the black wire is what turned the compressor on and off because I couldn't find a black wire on the wiring diagram. Are you sure it is supposed to turn on and off witha 12V supply? What does it mean if it doesn't do so?

The AC was working so-so when I started the job of changing it over, so I'd be surprised if the compressor was the problem.

I changed the expansion valve on my FJ62 a few years ago. It's not that bad.

 

[thetaxmonkey]

you should get some response when you jumper the 12+ on battery to the black wire that runs across to pass side fender. have you checked your grounds?

 

[euclid]

Yep, ground good. No repsonse with a jumper. I'll try again tonight.

 

[Waggoner5]

Greg, call my cell.
871.307.6141

 

[euclid]

Finaly got it. Thanks to Wagoneer for the colaberation, and to Texican for the offer of colaberation.

Turns out the problem was in the guages. Started at one end of the guages and worked my way towards the compresor. Opened each fitting looking for preassure. All was good UNTILL I got to the last fitting, the quick connect that connects to the compressor. For some reason pressure wasn't getting past that fitting. Dis-assembled the fitting, re-assembled it and all is back to normal.

Still don't have a correct reading on the high side guage, so I'm wondering if my guages are taking a dump.

Next question.. how much freon do you put in your FJ60? This one took a little more than 2 12 oz cans to get correct low side readings. Book calls for 1.25 pounds.

Thanks again for your help.

 

[Waggoner5]

A little more than 2 cans is what I used. I added until the low side was in the 40s and the high side was around 150. It blows really cold and does not build to much high side pressure when idling.
Glad you got it worked out.
G

 

[euclid]

I quit when the low side hit 33. Might add more later.