oneblueyedog

Howdy,

I installed a complete Performance Aire system around 10 years ago. It has worked great until it blew a hose (D side to condenser on air intake) Got the hose fixed, resealed the compressor shaft seal (second time) and pulled a vacuum. Held steady for a full 24 hrs.

I'm thinking about going R 134 (flush lines, new receiver drier, etc).

But this decal has me puzzled. Does it mean that you can only charge this system trough the D side, and does that mean engine off, charge with r134 to capacity (what the capacity is I have in Bentley?). Test pressure of Suction and Discharge. If pressures are off (taking into consideration ambient temperature) add more to the D side?

Why not add through S side (low side)?

Thanks for any help.

theiceman

all i can tell you is that my audi you charge through the high side only also .. and not with those litttle cans.

rusnak

I'm confused by the term "D side". I'm more familiar with "low side" or "high side". Maybe the new technology is different than my setup.

What I do is evacuate both sides and pull a vacuum, just like you did. And then fill to the low side while monitoring both high and low pressures.

I did convert to 134a, but that's because it's cheaper than R12, and at the time I was plugging expansion valves are receiver dryers like crazy. The PO had let the system sit without pressure, and there was dirt and gunk in there.

Since your system works, and you have got it worked out, I would stick with R12, no question.

griffiths

D = discharge; compressor to condenser
S = suction; evaporator to compressor

rusnak

^ aha! Thank you! Yes, that makes sense.

oneblueyedog

I spoke with a gent at Scotts Independent and he said in my case pull a vacuum on both sides and then close off and add refrigerant with both valves open while watching the high side (D). When the High side needle starts to move up, close the High side valve and continue adding refrigerant to the low side until correct pressures are reached. Will stick with R12 though. The stock condensers are inadequate for r134.

He also said to add refrigerant immediately after evacuating and boiling off the moisture since the seal on the compressor is a pressure seal that uses the charge to keep it sealed up. He said it was great that mine held, but since it was slinging oil, I'm replacing it.

So I will reseal the compressor and replace the receiver drier.

griffiths

Did this chap tell you to add the refrigerant by "gas" or "liquid" method?

oneblueyedog

Hmm I did not get a clarification . I assume gas?

griffiths

I was reading the brief procedure you were going to use and just want to insure you know how to charge the system:

After evacuation;

Liquid: engine off, charge through high side only, use weighted charge method.

Gas: engine on, charge through low side only, use weighted charge method.

Adjust final charge based on pressures and temperatures.

oneblueyedog

Thanks Griffiths. I've read too that High side (D) is the danger side if engine is on. That's why the decal got my guard up. It was not clear to me. I don't have R12 in bulk or scales so this is going pro.

oneblueyedog

Carefully peeled back the prestite tape from the evaporator an unclipped the coiled tube leading to the expansion valve. Polished it and the evaporator tube with 400 grit to shiny. Removed the rust from the clip. Clipped the assembly back on an remashed the prestite tape. How much prestite is applied? I'm using original amount. Since the clip rusted, it's not an airtight seal.

griffiths

Don't know why you are focusing on the TEV's sensor, however the TEV's evaporator outlet sensing bulb (the copper tube coiled like a pig tail) needs to be attached to the TOP of the evaporator's outlet tube, held down with a clamp and covered with 1 to 2 layer's of Prestite. And, any spaces between the evaporator box and the evaporator's tubes where they exist the box should be sealed with the tape. You do not have to wrap the entire TEV in tape.

oneblueyedog

Thanks Griff. When I installed this system many years ago, PA made a point to service this area like this. She made a point that it was pretty critical and neglected. Over the last 10 years it became pretty grody again, although I could see tiny contact points on the tube that were lighter in color than the brown CU tube. The clip/clamp was rusty. I assume it transfers heat too, so rust is not a good conductor. I just wire wheeled it. I guess I'm ok with the factory prestite wrapped as it was. Just looking to improve.

griffiths

The TEV is not the issue, however if you enjoyed going over it then it is good exercise.

If you are blowing hoses and nose seals then you probably have an issue with excessive high side pressures. This can happen if for example you run the AC system with the engine deck lid up for awhile (no air is moving through the condenser). If you have a front OEM condenser and it blower motor fails.
You overcharge the system. And a few others.

oneblueyedog

Naw it wasn't that enjoyable. But not as tedious as putting the cover plate back on the compressor with the new seal. What a difference from the last time. The lip seal is a Santech MT2279. The hunt for it finally ended after I took a picture with a mm scale and emailed it to Santech. Klaus helped me and replied back in minutes. Did a search on Google and 4th down the list was AutoZone. Less than $10 but special order.

Griff you mentioned a seal install tool. I used heat shrink tube last time but that did not work at all on the shaft. The seals must be a new design. So I got a brass tube a little smaller than the diameter of the splined shaft. Layered up heat shrink tube over the end to overlap it to not cut the seal. Then I needed a tube to go over the splined shaft and just a little larger than the shaft surface the seal rides on to ride over the step.

I used a chromed golf club shaft. I use them to punch holes in wood and rubber.

Started the gentle stretch of the seal inward with the brass tube. Then fed the small end of the golf club shaft against the overlapped heat shrink of the brass tube the opposite direction passing back out. The gradual steps of the chrome shaft stretched the seal concentrically to the end diameter that I cut to slip over the splines and over the step on to the shaft.

Zoop- it slipped right on. There was plenty of refrigerant oil bathing it all.

Buttoned it all back up and it's ready to bolt back on. I'll pull a vacuum this weekend.

I will check on function of the front condenser fan. I thought I heard it but now I'm not so sure.

One more thing, when I pulled a vacuum with the replaced hose before all of this, it held for weeks until I took it apart (last weekend). As I disconnected the high side, the o-ring disappeared. Like, vaporized!

I took the hose off and blew it out with compressed air. Fished around the engine bay. I was really sweating it. When i took the compressor rotary part out of the housing, it was in the back end of the housing, ready to compress back into the system (condenser). Lucked out.

Working on AC is not a common DIY task. I think suspension bushings are easier. Hats off to you guys.