Driving around Phoenix, AZ in the summer time without ac sux! The ac in my 77 works and blows ice cold but I'm always weary about running it because the pulley wheel on the compressor squeels and the engine runs a little rough. I also don't run for fear of overheating. Is there anything I can do to get my ac working 100%?

 

If the compressor is making noise when engaged you will need a new one.
If I'm reading you right the clutch is slipping when engaged and the rough running is due to the engine working overtime to turn the compressor.
A/C is nice but it ain't cheap!

 

I second that it is time for a new compressor. Like oldmetal said from your descriptive it sounds like squealing noise is your clutch slipping.

 

Either the compressor or the compressor clutch is likely. But let's not put the cart before the horse. Is the belt tight and in good shape? If it is glazed over or slightly loose it will squeal when the clutch kicks 'on'.

If it needs just the compressor clutch that can in most cases be replaced without to many pain in the rear issues. But any noises behind that clutch can point towards the compressors internal bearing issues.

Basically if that compressor is over 10 years old? That's a good run for it.

S-

 

Why is AC work so expensive? I took mine in for a diagnosis. They claimed I needed a complete AC overhaul to the tune of $968 plus tax.

 

Complete overhaul? Ughhhhhhhhhhhh...

A/C work now'n days is an art form with techs that are highly trained. (and highly paid normally---or at least the shop they work from is) R12 is a big no-no...Everything going into a shop gets R134a. Under normal ideal conditions? Change out the fittings, drain and change out the old R12 oil from the system (note: some newer style oils can work with the older R12 oils) If the receiver/dryer is getting on in age? That gets changed out. Vacuum out the entire system for 30 minutes to ensure every drop of moister is removed. Charge and leak/performance test the system.

The compressors are the big ticket item for list price, followed by the evaporator and condenser. Other then that? Normally the receiver/dryer and the neato valve that controls the flow of the now pressurized liquid R134a into the evaporator.

I can see if they replaced the entire set, along with hoses? Yeah...that can run into the big dollar amounts. But that also points to a shop that either can't figure out leaks...or is trying to pad up the bill. I've yet to find ANY car/truck that needed to have the entire system replaced. But that's just me, and the last time I did A/C repair work was 15 years ago before my cert. ran out.

S-

 

Yeah, I figured they were trying to fleece me because they couldn't properly diagnose the problem (or didn't want to spend the time doing it). I won't be doing business with that shop.

 

The oils don't mix. Two kinds of oils are used: R22=mineral oil / R134a=P.O.E. oil. You don't pump down a system by just using time. The correct way to do a system is first test with nitrogen for leaks. Then purge the system with nitrogen to remove as much moisture and other stuff from the system as possible. If you are using R22, you then pump the system down to 500 microns. If you are using 134a, then you do what is called a double evacuation by pumping the system down past 1000 microns, break the vacum with nitrogen and then pump it down to 500 microns. Any time you have the system open for an extended period of time or are changing refrigerant types, always change the filter/dryer. Just pumping the system down by time doesn't work because you have no way of detecting a small leak or if you still have moisture in the system. There are a lot of theories but this is what the text books and E.P.A. say. $968.00 seems a bit expensive to me. Shop around......

 

I don't think it's my compressor that's the problem. The noise is coming from that clutch. The belt is maybe a year old and I tightened it a few weeks ago. Where can I find a replacement clutch at?

 

If the clutch is squeeling, the noise may be coming from the clutch itself, not from inside the compressor!

Do not throw money at it till you are sure.

Most compressors don't come with the clutch, and once the new compressor and original clutch is installed, the noise may still be there, because...

..Inside the clutch is a replaceable bearing. This is the problem when the clutch makes noise, all you need is the bearing, not the entire clutch, field & pulley assy.

C9AZ2990A .. A/C Compressor Clutch Bearing (Motorcraft YP20)

Fits: 1969/79 F100/350's, Bronco's & Econolines, and most of the cars / Available from NAPA, most autoparts stores & shops that specialize in A/C work.

There are also one or two A/C idler pulleys on the engine. One or both could be bad.

These parts were a major seller back then, because they were a POS from day one.

We used to call these "miracle" parts, because if one lasted a year, it was a miracle!

 

A/C is expensive because it is a PITA sometimes. We have a car at work that was misdiagnosed as being a bad compressor (before I worked there) and customer came in to have the job done. Compressor was put in and not the problem. Now we are footing the bill for a rental car while we find the actual problem. Bad for us. Good for customer. But this is only right since it wasn't the customer's fault. Guy who checked car has ASE certifications. He also cut a hole through a manifold today while doing exhaust. Needless to say he will be spending a lot of time on monster.com in the next few weeks . I'd even be more then happy to help load his box for him too. Then maybe my blood pressure will drop to a normal rate again.

 

Sounds about par for the course. Being ASE certified is just about doing a written test. Where I used to work it was combined written test, plus working the field until deemed able to do the job without supervision by the "teacher" of the shop.

Mistakes can be highly costly. A/C systems are crazy easy in their operation, however it's all to easy to overthink things--ignore the usual problem areas and go for what's easy. Back in the day I wound up showing up the head mechanic several times by just knowing how to read the gauges better then he did LOL. One customer came back with a legit problem--not blowing "cold enough". Head mechanic downplayed it saying it was working 100%, and it was in the normal range for temp. So the shop manager had me do a basic check, sure enough? Charge was about 1/4 pound to low. Enough of a charge to get about 15deg lower then outside air---however with the proper charge? 20 deg lower would be ideal according to specs and getting the gauges back into the butter zone. (it was reading the lower end of normal when it came in). Needless to say? Customer always asked for me for the yearly checkup.

Now'n days most of these "techs" wouldn't know the difference between their fanny and a hole in the ground. Ask them to locate the source of the leak? They will start throwing parts at it.

S-