Impromptu Workshop

[GTRS Fiero]

No rush.  Just curious.

[Fierofool]

This is the original compressor as it is installed in the car.  You can see the refrigerant tubes and the pressure switches.


The pressure switches are unplugged amd visible.  Next is to remove the single bolt in the center of the refrigerant tube manifold and pull the refrigerant tubes away from the compressor.


Once the compressor was out, the receiver dryer was removed and the refrigerant lines back flushed with AC System Flush.  This system uses a siphoning container and compressed air.  It's best to flush from the front to the rear with a container underneath to catch the oil and flush.  Flushing from the rear will fill your front compartment with some messy stuff.


Once the system is flushed, the new receiver dryer and orfice metering tube is installed.

[GTRS Fiero]

In the first 2 pics, what is the bulbous thing inline?

[Fierofool]

With the old and new compressors on a workbench, remove the plugs that come in the new compressor and transfer the pressure switches from the old compressor to the new compressor.  It doesn't matter which port the pressure switches are inserted into.  They both sense pressure from the same chamber.  One is high-pressure safety and the other is low-pressure safety.  These are often thought to be the switches that turn the compressor of and on.  That function is handled by the pressure switch that is mounted on the receiver dryer upfront.  If converting from R12 to R134a, just spring for an R134a pressure switch instead of fiddling with trying to adjust the R12 switch to the proper pressures.  The switches are cheap and aren't 30 years old. 


Work the compressor back into position and install its mounting bolts.  This was found to be a chore with 1 specific bolt.  Chamfering the end of the threads was of great help in getting the bolt started into the compressor dog ear.


Once all the mounting bolts are in place, the pressure safety switches can be connected and the refrigerant tube manifold can be bolted back to the compressor.  All connections that were separated received new O-rings or appropriate seals, lubricated with Nylog Blue AC lubricant and seal. 


Once everything is bolted in place and the tension is set on the compressor belt, the refrigerant recovery/recharge equipment can begin to evacuate the system to remove all moisture and to check for leaks.  Once the system is determined to have no leaks you can start to charge the system.

[Fierofool]

That bulbous thing is a muffler of sorts.  It works similarly to the pulsator on our fuel pumps.  It absorbs and softens the compressor pulses.  It's nothing more than a hollow canister on the output side of the compressor. 

[GTRS Fiero]

I don't recall seeing that on mine.

[Raydar]

That bulbous thing is a muffler of sorts.  It works similarly to the pulsator on our fuel pumps.  It absorbs and softens the compressor pulses.  It's nothing more than a hollow canister on the output side of the compressor.

I had to have my lines re-welded when I changed the configuration of a motor mount.
The guy who did the work said that the muffler was not required. (It was seriously in the way.)
My A/C works fine without it, but the compressor seems a bit more noisy. Hope it's not hammering the innards to pieces.

[GTRS Fiero]

That was my concern, also.

Do newer cars have this?

[Raydar]

Charlie,
Which washers did you use when you hooked the refrigerant lines back to the compressor?

[Fierofool]

I just checked my 2008 truck and it has it.

[GTRS Fiero]

Uh, oh.

[Fierofool]

Charlie,
Which washers did you use when you hooked the refrigerant lines back to the compressor?

I purchased a kit that had oil, expansion tube, receiver dryer, and a good selection of seals.  The seals seemed to be for the compressor because the green O-rings were generally of a smaller gauge than what was needed on the expansion tube and receiver dryer connections.  Fortunately, Brown's Fiero Service Center had what was needed.

You can see on the new compressor that it doesn't use the standard O-rings.  One of the surfaces is flat, so it uses the flat metal washer with the rubber seal insert.  There were a couple of seals in the kit with various inner diameters.  We selected the one that properly fit over the refrigerant tube. 

The other port is recessed.  The kit also came with a selection of seals for this port.  There were several thicknesses but the one that fit into that port was about 3/16 thick.  Just enough to slightly stand up above the shoulder of the port.  They appeared to be aluminum rings with the rubber center seal. 

[Raydar]

My compressor had depressions of two different depths. I had to use a thick washer and a thinner washer. Was curious as to which ones worked for you, as mine was kind of a toss-up. 
There were also aluminum bushings/inserts of two different lengths. I had to drive one of them (I forget which one) into one of my refrigerant lines. The first time I did the washers, I didn't realize that the bushing was needed, and over time, the movement of the refrigerant tried to suck the rubber seal out of the center of the washer, into the gap. 

[Fierofool]

There were no bushings provided. I'll have to look at a set of lines when I get back k home to see if something is needed .

[Fierofool]

I checked 2 sets of hoses and they are both the same.  Where the compressor manifold bolts to the compressor, the tubes protrude through the manifold bracket and would insert through the seal and into the case of the old compressor.  For the new compressor, only one of the tubes will insert into the compressor while the other is only long enough to fit into the rubber portion of the recessed thicker seal.  That tube is the proper diameter for the seal we chose but may exhibit a similar situation as you experienced.