3FE - troubleshooting A/C issue

[alphaeighteen]

Hi,

I've been searching for a while and think I have found one for the issues why the A/C is not working. I think I'm missing a belt. ( 1st time mechanic but learning quickly)

I've attached 4 photos while trying to look at the internals of the engine and see if the compressor itself is working but don't see where it was attached.

How do I change these belts? It looks like the A/C is the inner most one so I'd have to take the other belts off to get install the inner one?

Thanks

 

[paulzak]

There are many good write-ups here to tell you how to do the job. Folks generally recommend using OEM belts and changing them all when you do one. The belts can be tough going on. If you're asking how to do this, you may want someone looking over your shoulder offering advice the first time. Be sure to have a FSM available. It can be a frustrating job the first time you do it with new belts.

 

[flintknapper]

You're definitely missing the belt that goes to your AC compressor, but it might have been taken off for a reason. I'd try to turn the compressor by hand before putting a belt on it. It might be seized.

 

[alphaeighteen]

You're definitely missing the belt that goes to your AC compressor, but it might have been taken off for a reason. I'd try to turn the compressor by hand before putting a belt on it. It might be seized.

How freely should it turn? I can't seem to turn it by hand. Maybe you're right it is siezed.

 

[1972FJ55]

The pulley where the belt rides should spin freely, sounds like it's locked up.

 

[alphaeighteen]

The pulley where the belt rides should spin freely, sounds like it's locked up.

Thanks - I've heard that you should also replace the condenser if you replace the a/c as well. Is this true? I was looking under the hood but didn't see the condenser clearly. Is it in front of the radiator?

 

[flintknapper]

Thanks - I've heard that you should also replace the condenser if you replace the a/c as well. Is this true? I was looking under the hood but didn't see the condenser clearly. Is it in front of the radiator?

Yes and Yes.

IF your compressor has seized there is an excellent chance it sent some small metal particles throughout the system (mostly the condenser) and you won't be able to flush that out. Condenser is the radiator looking part that sits in front of your radiator.

Not a terribly expensive item, that is the good news.

 

[Rush]

The pulley should be a separately replaceable component from the compressor... So while I agree you should be prepared emotionally to repair a seized compressor, it might just be the pulley bearing. That's usually retained by a snap ring, but in this case it looks like a bolt right in the center.

 

[alphaeighteen]

The pulley should be a separately replaceable component from the compressor... So while I agree you should be prepared emotionally to repair a seized compressor, it might just be the pulley bearing. That's usually retained by a snap ring, but in this case it looks like a bolt right in the center.
View attachment 2370547

Cool - I'm going to pull the compressor at some point anyways, so I'll check the pulley bearing. Would the pulley bearing be locked up? What's the best way to check this?

 

[Rush]

Cool - I'm going to pull the compressor at some point anyways, so I'll check the pulley bearing. Would the pulley bearing be locked up? What's the best way to check this?

I'd remove it from the compressor and inspect. That it doesn't turn freely without 12v to the clutch (this is an assumption, try turning it with the key out, completely off to be sure) is the complaint, now to find the component that is causing this.
My guess is, unless the clutch welded/rusted itself engaged, it's just the bearing.

But that's just a hunch. Get the pulley off the compressor, and see if the bearing turns.

 

[flintknapper]

Cool - I'm going to pull the compressor at some point anyways, so I'll check the pulley bearing. Would the pulley bearing be locked up? What's the best way to check this?

You can tell if the pulley bearing is rough or locked up right on the truck, no need to remove it. It normally 'free wheels', just reach down there and spin it. The way your Compressor Clutch works is that the pulley spins freely (driven by the belt all the time), when your A/C unit is turned on...it activates the 'coil' which pulls the clutch against the drive plate on the pulley (coupling the two) and this is what turns your compressor. It's just an electromagnet.

So....yes your pulley bearing could be bad, but so too could be your compressor (either could be rough or seized) just know that. I would leave the pulley on there and spin it. IF it spins freely without noise, gritty or wobbly...then I'd bypass the binary switch (hook 12v directly to the connector) and see if it will engage (it will click as it pulls up to the drive plate) that way we know the clutch AND pulley are both good and we can move on to testing the compressor itself.

 

[alphaeighteen]

You can tell if the pulley bearing is rough or locked up right on the truck, no need to remove it. It normally 'free wheels', just reach down there and spin it. The way your Compressor Clutch works is that the pulley spins freely (driven by the belt all the time), when your A/C unit is turned on...it activates the 'coil' which pulls the clutch against the drive plate on the pulley (coupling the two) and this is what turns your compressor. It's just an electromagnet.

So....yes your pulley bearing could be bad, but so too could be your compressor (either could be rough or seized) just know that. I would leave the pulley on there and spin it. IF it spins freely without noise, gritty or wobbly...then I'd bypass the binary switch (hook 12v directly to the connector) and see if it will engage (it will click as it pulls up to the drive plate) that way we know the clutch AND pulley are both good and we can move on to testing the compressor itself.

View attachment 2370870

If I understand this correctly, I tried to spin the clutch before and it was not spinning. However, I should also test by spinning the pulley behind the clutch? I guess I'm not understanding why the failed pulley would be able to spin but the clutch isnt if the pulley is bad.

 

[flintknapper]

If I understand this correctly, I tried to spin the clutch before and it was not spinning. However, I should also test by spinning the pulley behind the clutch? I guess I'm not understanding why the failed pulley would be able to spin but the clutch isnt if the pulley is bad.

The clutch is connected to the compressor by a shaft, it will NOT turn freely...it requires a good amount of hand force before it will move, especially if it has been sitting for awhile. It might even take a strap wrench to 'free it' IF the compressor isn't seized. If the compressor is seized...then it's game over. ONLY the pulley will free wheel. IF it also is seized then it needs to come off.

 

[alphaeighteen]

The clutch is connected to the compressor by a shaft, it will NOT turn freely...it requires a good amount of hand force before it will move, especially if it has been sitting for awhile. It might even take a strap wrench to 'free it' IF the compressor isn't seized. If the compressor is seized...then it's game over. ONLY the pulley will free wheel. IF it also is seized then it needs to come off.

Got it - that's clear for me. Will take a look at this one, thanks.

 

[flintknapper]

Got it - that's clear for me. Will take a look at this one, thanks.

Happy to help and proud of you for taking the initiative to learn about it and make the repairs (where possible) yourself. Not many young folks doing that these days. Good job young man!

 

[alphaeighteen]

Happy to help and proud of you for taking the initiative to learn about it and make the repairs (where possible) yourself. Not many young folks doing that these days. Good job young man!

Had some time to experiment today. Looks like the front section (clutch spins) but the pulley is not spinning. Am I understanding the pulley should also spin too? I put down some considerable force on it and it will not budge. I also seem to be missing the 12v connector? Something is disconnected in the rear

 

[alphaeighteen]

Tried to fix it a little more since it's hot here in socal. I tested the red and black Schrader valves on the compressor and heard some hisses so I didn't want to pull the compressor. It seems like there is still refrigerant in there.

I'm trying now to get the clutch off to replace the pulley since that seems to be stuck. However I'm having difficulty removing the clutch since Everytime I spin the bolt the clutch spins with it. Anyone have any advice on how to remove the clutch so I can get to the pulley?

The compressor is still on the vehicle.

 

[alphaeighteen]

Another note, I'm feeling like there should be readily available high and low sided pressure ports but I cannot find them for the life of me. Is it possible that the PO changed the lines to not have ports for charging? Or are they located only on the compressor itself?

 

[BILT4ME]

Another note, I'm feeling like there should be readily available high and low sided pressure ports but I cannot find them for the life of me. Is it possible that the PO changed the lines to not have ports for charging? Or are they located only on the compressor itself?

Those are right there in the picture you posted. One with a red cap and one with a black (grey) cap.

Red is TYPICALLY high pressure, Black is typically low pressure.

You have a 3FE which means it was originally charged with R12 freon. Not readily available these days and it does NOT look like it has the adapted fittings to indicate someone has changed it over to R134 freon.

Converting it from R12 to R134 will require a number of parts. If you're already having problems with the compressor, then you should seriously consider a new compressor, drier, expansion valve, and possibly even a condenser (in front of the radiator). Hold on to your wallet.

Some of the 3FE folks here can post available alternate parts for the AC system on your truck. Start looking at RockAuto for Denso brand parts.

Most of this you can change out yourself, but you'll need specialty tools to flush, evacuate, and recharge the system. You can do all the parts replacement, then take it to a shop to have the F/E/R completed.

 

[alphaeighteen]

Those are right there in the picture you posted. One with a red cap and one with a black (grey) cap.

Red is TYPICALLY high pressure, Black is typically low pressure.

You have a 3FE which means it was originally charged with R12 freon. Not readily available these days and it does NOT look like it has the adapted fittings to indicate someone has changed it over to R134 freon.

Converting it from R12 to R134 will require a number of parts. If you're already having problems with the compressor, then you should seriously consider a new compressor, drier, expansion valve, and possibly even a condenser (in front of the radiator). Hold on to your wallet.

Some of the 3FE folks here can post available alternate parts for the AC system on your truck. Start looking at RockAuto for Denso brand parts.

Most of this you can change out yourself, but you'll need specialty tools to flush, evacuate, and recharge the system. You can do all the parts replacement, then take it to a shop to have the F/E/R completed.

Thanks for the advice. Those are the ports that I pressed the valve down on and there was a slow hiss. But nothing to indicate that it is highly pressurized. I bought some manifold gauges but it doesn't seem like they have the proper connections to the ports unless I'm missing something. I believe that R12 has different connectors?