fragmare

So I recently rebuilt my A/C compressor. The clutch bearing was bad and due to the heat created by said bad bearing, the spindle on the top assembly had become warped and the field coil suffered some damage. I hit up the local junkyard and swapped out the clutch bearing, spindle assembly, field coil. The internal ball bearings, thermal protector, relief valve and clutch/pulley clearance were all fine. Everything now checks out with the newly rebuilt compressor.

Anyway, i pulled a vac on the system and recharged it with 3 oz. of ester oil (the compressor had about 1oz of ester oil left in it when i reinstalled it) and roughly 20 oz. of 134a. The drier was also replaced.

Got out the manifold gauges to run the test and it seems the high side pressure is a tad high. Resting pressure seems like it's a little higher than it should be too.

For any of the A/C experts here, does this sound like a restricted expansion valve? the expansion valve was replaced last summer. I'm not beyond tearing the thing apart again and replacing the EV, but I'd rather not just throw parts at the thing before I know what's wrong.

Here are my results (diagram also attached):

Ambient Temp - 32C/90F (measured in front of condenser)
Ambient Humidity - 80%
Delivery Temp - 19.5C/67F
Low Side Pressure - 40 PSI/276 kPa @ 1500 RPM
High Side Pressure - 330 PSI/23.2 kg/cm^2 @ 1500 RPM
Resting Pressure - About 100 PSI on both sides

Former User

93 Civic with OEM A/C system? What weight of R134a is specified for your system?

The static pressure is fine.

Does the condenser fan run? Are the condenser fins clogged with bugs/road debris?

Any kinked refrigerant lines?

When you replaced the expansion valve last summer, did you clean the evaporator fins with compressed air?

fragmare

The condenser fan runs, and in the correct direction. Not sure how to check the RPMs on it though. The condenser fins appear fine, but I should probably shine a line behind it and see how much light shines through... good point.

No kinked or bent lines.

Yea, i took the evaporator completely out and cleaned it as best i could. It was pretty horrible. Looked like a birds nest. It's much better now, though.

Former User

Also, did you possibly overcharge the system?

fragmare

oops forgot to answer your first question...

Yes, 93 Civic DX with all OEM parts. I believe the proper amount of R12 was 23 oz. The Honda retrofit bulletin says something to the effect of "Determine the amount of R-134a refrigerant needed to charge the system by subtracting 50 ml (1-2/3 oz) from the system’s R-12 capacity." Going by that, it should take 21 1/3 oz. of R134a. There is about 20.5 oz in there now, so that's pretty close to the mark.

Former User

Did you use the R12 chart to plot your R134a performance test results? If so, I don't think that's valid. Try replotting the data on the 96-00 Civic R134a chart to see whether you come to the same conclusion.

Does the A/C blow cold? Satisfied with the cabin cooling?

fragmare

Ah, good point. Have a link to an image of the 96-00 chart?

Former User

...

fragmare

awesome! thanks, Ron.

and we'll see about the cabin cooling later today when i take the car to work.

fragmare

Okay, this looks MUCH more accurate for the amount of r134a in the system. If anything I could afford to add in the extra ounce of 134a, which I think I will go do right now. Again, thanks Ron.

fragmare

Btw, I still have the junkyard compressor that I cannibalized for parts. Would there be any interest here on a video tutorial (Eric the Car Guy style) on how to rebuild/repair A/C compressors? I'm sure there are a lot of people here who are going out and buying new compressors when they could simply fix the one they have.

Former User

Definitely! Please create a DIY thread with nice pictures. Thanks.