AC Rebuilding Quesion?

[FuzzFace2]

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 ----

[old55pete]

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 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.

[85lebaront2]

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 ----

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.

[85lebaront2]

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.

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.

[old55pete]

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.

[71_badmach]

Dave, I will give you what I have gleaned from the A/C classes I have taken over the last 20 years or so. In some states you HAVE to recert for A/C every couple of years and cant buy more then 3, 12 oz cans of R134 at a time if you are not certed. Welcome to California drewling into AZ.

1 The the blue orface tube should be fine for your pickup. It had a white one from the factory but the blue will work better the R134

2 If you are going to use R134, you need to be using Pag 150 oil with green die in it as the die will show where leaks are. You can use Ester oil, but pag 150 is recomended by Sanden and most of the major compressor manufacters. We have been told for years that Ester oil when used with R134 sets up a chem reaction that eats the aluminum parts in the system over time. The older the system, the quicker the reaction.

3 According to the Ford service manual for an 86 F150 regular cab, It has a 3 pound system. In that case, you need to add 1 oz of pag 150 for every 2 lbs of freon so an ounce and a half should be fine. Add the oil after you vacum down the system or at the same time you add the freon through the low side port.

4 You need to change the pressure switch on the accumulater/ dryer to an R134 switch as the pressures run a little different then they do with R12. The NAPA part number for this switch is TEM 207887, you can cross that to what ever parts source you want to.

5 Once you have the oil and freon added( you may have to start the engine and turn on the A/C to get the third lb in). Once all of that is done, watch the guages as the comperssor cycles. On the low side, the compressor should come on at around 22 lbs and shut off around 45 lbs, on the high side the compressor should shut off around 250 to 300 and come on around 100 psi. Some where between 250 and 300 lbs on the high side, the engine fan should kick in and drop the pressure. If the fan DOES NOT come on and drop the preassure , shut the engine off and replace the fan clutch. It the pressure is too high it will cause damage to the system.

Dont take any of this as gosple, it is just what I have learned as a truck and heavy equipment machanic over the last 20 or so years. I am sure someone on on this site knows a better way and has more nolage then me as even I am still learning

Many thanks for this detail and the "nugget" about changing the pressure switch over for R134a. And to the original poster, Dave, for posting on some of the aspects of this modification. I haven't gotten as far in my build yet, but I went with a serpentine conversion system that has a "peanut" Sanden compressor setup that I will be plumbing in eventually.

Hope you have had success in getting the pulleys sorted out.

Dave, I don't think you will have any of the problems with the 302 as I do with the 300 and even less with that belt set up.

Did your truck have AC from the factory or something else?

Good luck with your build.

Dave ----

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.

[Rusty_S85]

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.

[FuzzFace2]

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.

[71_badmach]

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.

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

[FuzzFace2]

That's 'spensive!

As for the pulley, unless it is in the original packaging the seller won't know the part number. So they'll be listing it via ID # that's on it. So for part # E0TZ 8509-B you would be looking for E2TE-BA. Or, sometimes the manufacturer put the whole code on, so it might be E2TE 8509-BA.

Gary, thanks for the break down. I searched with a O and a 0 space and no space, think I even tried 8509, but did not think to try the E2TE-BA as I did not really know what that was.

Wish me luck as I will try every combo I can think of LOL

Thanks

Dave ----

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.