AC Rebuilding Quesion?

85lebaront2 wrote

Pete, you do not need to change the pressure switch, it is adjustable with a screwdriver. You need to make a short pair of male on one end, female on the other jumpers so you can remove the plug, connect the jumpers across from the switch to the plug then adjust the cutoff pressure for R134.

I did this on Darth and the 1990 Lincoln Town Car we owned. Matt and I drove it to an R134 conversion class and the fellow doing the class was so happy to have an R12 to R134 conversion to demonstrate on. Only recommendation was to replace the emergency relief valve with a high pressure cutoff switch.

Bill, I did check the switch and it is adjustable just did not look like it was a flat blade type?
What I am not following is what you are doing with the jumpers?
Is it so you can um-plug the harness to access the switch adjustment but still have it connected to the system / harness?

IIRC it is a low PSI cut off switch so at what PSI should it cut off / on at?
What if you adjust the switch and with gauges when it hits that PSI when it should come on you plug the harness back in and see if it works and if not adjust and try again?

Local NAPA would have to order it for next day and it is for R134A.
Auto Zone has it in stock but only lists the one for the R12 system. On a review someone said go with 96 truck but it list the same switch number or different switches with different plugs.

If I know the PSI for the 134A I will try and adjust mine. Heck I could make a rig to use shop air and a meter to set it before I install it in the new dryer.
Dave ----

Bill, I do know that the r12 switch is adjustable, here is my reasoning for changing it to the 134 switch. I am a shop owner just as you once were, if I understand correctly. To build a jumper system to get a screwdriver in there to make the adjustment takes time, at a $95.00 an hour shop rate, all of the little things like that add up quick. The switch is around 10 bucks and takes about five seconds to change. In short, it saves me time and saves the truck or equipment owner money and the system works right the first time, no guessing.

Now Dave is talking about taking the time to buy the stuff to make an adapter to use compressed air and make the jumper system to adjust his switch to the right pressures when his time would be better spent figuring out his belt and pullie system.

I am not, by any means trying to start an argument. I was trying to save the guy some time and money, As time is money.

At this time, I will keep following this thread, but will no longer comment.

What you found on the switch is not surprising, the switch screws on to a port that is essentially an R12 fitting for the gauges. The pressure temperature curves for R12 and R134 coincide at 60° F, below that R134 pressures are lower, above that they are higher. Since the port the switch goes on didn't change, and the switch is adjustable it stands to reason that many sources will sell the same switch and list it for both. Here is a temp pressure chart that may help:


The switch has a pair of 1/4" wide (I think) male flat blade pins, the plug has the female portion. I made a pair of around 2" long, enough to allow the plug to be moved far enough that I could get a flat blade screwdriver into the adjusting screw. You want the pressure about 29 - 30 psi so the evaporator temperature will be near 34° F to keep it from freezing over.

This was how I set the switches on Darth and the Lincoln. Both worked quite well, Darth now has a 1996 HVAC system with all the improvements. FYI, it is physically a bolt in as far as the underhood and inside casing are concerned, but the wiring routing changed and the inside has an added "demister" portion to put dried air on the wing vents when using the defroster either as a mix or full.

Pete, he is working on it himself, so his time vs paying someone to do it I am sure has been considered. I do this myself, some things, like the cooling system flush and replacement on my Flex go to the dealer, most everything else I do, even to the point of having already bought the timing chain replacement cam holders for it. Water pump is the center idler for the timing chain.

Right now, I have a Taurus that ate it's FS10 compressor about 2 weeks ago. I have to remove it, put a bypass pulley I keep handy (fits Taurus and truck) and then see how much crap it put into the system so I know what I will have to replace.

Bill, as I said earler in this thread" dont take what I say as gosple as someone will come along that knows more then I do". You sir have arrived and now I will become the student. I also said before that I dont know everything and am my self still learning..............To that end, as my dad would say, you learn with your mouth closed and your ears opened. Please sir, drive on so that I too can learn something new.

Dave G.,  yes my truck is an 85 XLT with factory air.  Not sure the shape of the other components, I removed the compressor that was sitting there with no belt and associated hoses to get them out of the way.  

I had the original EFI setup on it and it was running well, until I started having starting issues last summer.  Not being electrically savvy, or wishing to delve into sorting out old, first generation EFI, I decided to go with aftermarket Edelbrock ProFlo4 since it was easier to get there from EFI than go back to a carb setup (although a little more pricey )

Appreciate reading all the discussions on here.  I will chime in and say working in a Hot garage in South Mississippi, the $10 switch option is the route I'd be taking... haha

Good luck with your endeavor, and thanks for asking.  

How is that Edelbrock setup working?  I looked at it but settled for the Sniper Stealth since it has a C6 kick down linkage vs the Proflo that would require a lot more customization to make work out of the box.

Thanks guys for all the comments good or bad we all learn.
As for the time vs money as Steve put it I can see his way of thinking.
My time is just that my time so not much money to it.
As for adjusting my switch or get new I will most likely go new from NAPA as it is listed for R134A where the AZ one for any truck even up to 96 was listed for R12.
Also it looked like a PITA to adjust the switch and who knows if it worked before I got the truck even if they say it held psi till they took out the condenser with the motor.

I member has come up with the water pump pulley I need so I should be good to get the system vacuumed down & leak checked then filled I hope this coming weekend.

Thanks again, with out the help from members I could not get this AC system and other things worked out.
Dave ----

edit: I did buy the NAPA switch this way I don't have to mess with the old one and I know it will be 2000* in the garage when got to do this.

Rusty, haven't finished wiring or plumbing yet... hoping it'll fire right up.  I'll start a new thread when I get further.  

Jonathan,

Package showed up today just don't know when I will be able to clean / paint and install it.
Been up since 11pm last night for work just got home long enough to stuff a tuna wrap in me and back to bed as I got to be up at 2:30am for work tomorrow.

Then when I get home I have to make the weekly trash run with the pick up.
If I have anything left I will clean & paint the pulley. Sunday I have to cut the grass as I am loosing my cats in it, goofed off last weekend and did not cut it.

Thanks again for the part
Dave G.

Getting closer to having AC in the truck.

Today was work on the truck day.
In swapping the pulley I found the fan only had 3 bolts holding it on so had to make a trip to the hardware store so I replace all 4 bolts.
Got the ALY & PS belts back on but needed to get the AC belt for it as I returned the belt I had because it did not fit the smaller pulley that was on the wrong pulley.
BTW the right pulley was 1" smaller dia. (6") than the wrong one (7"), I don't know what that will do for cooling both the motor & condenser?

I then flushed the evap coil. I could not find the $50 flush kits local and no one has rubbing alky. with this virus going around so I used Prep Sol.
It is used in body work to prep panels before any work & painting to rid panels of oil and leave nothing behind.
What came out was clean just a little tint from oil that was it. I also passed a lot of air thru it to make sure it was clear of the Prep Sol.

Then figured how much oil to add to each part of the system and added it to each part. Ever try and pour oil into a small line? Not fun at all.
I put oil on the O-rings and installed all the hoses so I should have a sealed system if all is right.

With tools in hand I went for the AC belt, first tried the one I returned (17585) thinking with the 1" smaller dia. it may work and it did not still to small.
Then tried a 17620 and it was to big, had to go with a 17600 and was able to get it tight right there in the parking lot.

May try pulling a vacuum tonight just so I know the system is sealed but it is damn hot in the garage even with the fan blowing.
Yesterday I picked up a gauge set and vacuum pump from HF.
Dave ----

I have a question on wiring the compressor.
The York uses 1 wire, B - Y H and plugs into 1 wire on the York.

This new Sanden has a 2 wire plug, think Pink & Tan.
My question is, does it make a difference what wire I use to power the clutch and the other to ground?

Think this is the last thing needed before I can start to charge the system.

I did look up the wiring for a 85 and it showed the B - Y H 1 wire setup.
Thanks
Dave ----

Dave - I don't think it matters as you are just powering a magnetic clutch, so one side gets power and the other gets ground.  But I'd check with my meter first to ensure that neither wire is grounded already.

Gary Lewis wrote

Dave - I don't think it matters as you are just powering a magnetic clutch, so one side gets power and the other gets ground.  But I'd check with my meter first to ensure that neither wire is grounded already.

Thank you I don't know why I did not think to use a meter to see if 1 side was grounded all ready
I think what is throwing me off is the replacement pig tail has pink & tan wires but what I found and you are showing list the B - Y H wire and not what the pig tail has.
Guess they could use any color wire to make it?

Thanks again
Dave ----

Ford was pretty good about using the same colors across models of vehicles, but they might have changed the color to the A/C clutch at some point.  Dunno.

Anyway, if there are two wires it isn't likely one is grounded, but it won't hurt to check.

Gary Lewis wrote

Ford was pretty good about using the same colors across models of vehicles, but they might have changed the color to the A/C clutch at some point.  Dunno.

Anyway, if there are two wires it isn't likely one is grounded, but it won't hurt to check.

I did check and neither spade went to ground so I wired 1 spade hot and the other to ground and it worked.
Thanks
Dave ----

Well I don't know if I have a good or bad charge?
When I first started the vacuum pump it pulled down 10 HG so I let it set for 10 min. while I did other things and lost vacuum?
Did it 1 more time and was like WTH! Went over some fittings, rechecked the gauge valves and think I did not have it open all the way and in no time pulled down to 28 HG.
This time when I turned off the pump I pulled the line off the pump and put it on the gauge set. This time it held 28 HG for over an hour so called it good.
Put the pump back on while I did the electrical side of this install and it pulled down to 30 HG by the time I pulled it off a few hours later.

I could not hook up the high side of the gauge as it needs an adaptor so I have no reading on that side.
I put 1 12oz can in with the motor off as the vacuum pulled it in.
I started the motor and the pump was going on & off a sign of low charge. 2nd can the pump stayed on all the time as did the 3rd can. I did not add the full 3rd can only about half.

When done it was blowing cool but not cold. Gauge at idle reads about 45 psi and 50 on the R134 and when you bring the RPM up it drops but did not see to what.
It was 100* in the garage and with a IR temp gun was getting 69* out of the vent with fan on high.
As said it blows cool but not cold and does not feel like it gets colder when driving. You can feel it is cooler inside the truck when you get in as I did a trash run.

As I was charging the system I did not feel the vents blowing any colder than they do now like when I saw frost on the evap at the orifice valve area, also a sign of low charge IIRC.
I am using a blue orifice valve should it have been a different color? I was told that would be good.
So what do I need to do to get it colder? I would think as small as the cab is I should get frozen out. What did I miss?
Dave ----

This is my opinion. (Disclaimer). I would add refrigerant to about 60 maybe a tad higher.

I'm with Dane.

grumpin wrote

This is my opinion. (Disclaimer). I would add refrigerant to about 60 maybe a tad higher.

Gary Lewis wrote

I'm with Dane.

Someone else also said the same thing.
When I asked about how much charge it was listed as 2.5 cans and was afraid to add more.
I may need to pick up 1 more can and see if they have the needed adaptor for the high side just so I can see what it is at.
Thanks
Dave ----