[dataway]

Well, since I have all winter to accomplish this AC project ... hey, why not take a look at rebuilding the original unit right?

I'll start with seeing if I can track down the manufacture date to see if it was updated from the original 68.

If I screw up the rebuild ... well the compressor is about the easiest component to replace so no big deal.

[dataway]

While I'm at it ... has anyone here "rebuilt" an A6 ? I put that in quotes because I'm not sure what it means on an A6? Just seals? Are there other wear parts? Do the pistons/cylinders wear out? The wobble plate? etc.

[burd]

Hitting a swap Sunday, are you still needing R12?

[dataway]

burd, no, a PY member has set me up with a supply of R12, appreciate the offer.

[burd]

FYI, the cans are around $35 here at the swaps. I wonder if you can ship ups ground.

[gto4ben]

Originally Posted by dataway

While I'm at it ... has anyone here "rebuilt" an A6 ? I put that in quotes because I'm not sure what it means on an A6? Just seals? Are there other wear parts? Do the pistons/cylinders wear out? The wobble plate? etc.

My definition of "rebuilt" is changing the seals, upgrading the shaft seal to double lip type, and if required, the clutch, clutch bearing, and clutch coil. "Remanufactured" to me means taking the guts out, separating the two halves and if required, changing the bushings, thrust washers, pistons and rings as shown in the shop manuals.

I have rebuilt a few A6 compressors and collected or fabricated over time the correct tools to make it easier and without damage. Century Bob's videos are very good. I made a case holder to install the internals too.

After the rebuild, bench test the compressor in order to check suction and compression. You can use the driven clutch plate with the clutch tool installed combined with a socket and drill to rotate the shaft. I made a plate to cover the compressor ports out of flat stock and 1/4" flare nipples to hook up to gauges. Remember to fill the sump with oil to coat the bearings and flapper valves before the bench test or you'll get erroneous readings.

I had to make a long snap ring pliers out of a long needle nose pliers to get at the seal snap ring.

I attached some bench test data I took for you to compare as well as a picture of the test setup.

One more thing. For cleaning the internals, I used lacquer thinner. Other leave a residue and this is a good compromise. Final cleaning was done with AC flush. Seals were lubed with mineral oil but use the oil based on the refrigerant you intend to use.

[dataway]

Excellent info, thank you sir.

I have a 68 GM AC service manual here somewhere (supplement to the 68 service manual) Never looked through it very well, assume it has some good info.

[dataway]

So, back on to the AC project after a hiatus.

I'm thinking I should replace the expansion valve while I'm at it, since they are very affordable.

Question is, do I have to open up the evap case to install a new one, I notice the tube with the bulb at the end heads into the case.

Same question with the POA (?) valve, can it be replaced without pulling off the the evap case?

[dataway]

Just a holiday season bump

[69 Limelight]

While you're replacing expansion valve, and have removed sticky insulating tape from evaporator outlet line to R & R expansion valve evaporator temperature sensing bulb, do yourself a favor and get "Old Air Products" "DELUXE POA Valve Update Kit" which replaces problematic factory POA valve with an evaporator temperature sensing switch. (I don't think anybody refurbishes factory POA valves anymore.)

[dataway]

Yep I was thinking about going with the switched compressor POA. So it basically only runs the compressor when needed as opposed to running all the time when the AC is turned on?

Anyone know if I have to split the evap case to replace these parts?

[69 Limelight]

Correct on cycling. Has an evaporator temperature sensing bulb that is mounted on evaporator outlet line next to expansion valve temperature sensing bulb. When evaporator gets to low temperature preset temperature switch cycles compressor off when evaporator warms to preset temperature switch cycles compressor back on. The temperature range is very narrow so no wild outlet vent temperature swings like you get with the POA valve replacement that has been on market quite a few years and cycles based on pressure. I didn't install until late summer (like September) and ambientes were mid to high 80's but worked great with outlet vent temps in mid to high 30's (using R-12). Some people say AC A-6 clutch won't last cycling. IDK as I have a Pro6Ten compressor that has much less "pull" on engine than AC A-6. No you do not have to split evaporator case to install either expansion valve or Old Air Products "POA Deluxe Update" but unless you're sure evaporator core is clean, might be good idea. P.S. The temp switch that comes in kit may be somewhat adjustable as to cycling on/off temps as it has a piece of tape on switch housing that I suspect has access hole to adjustment screw IDK as I didn't remove tape to see what was underneath and it worked fine for me. I was going to call Old Air Products and ask but, never did. Good luck.

[dataway]

Thank you very much, very helpful information.

Evap is hopefully clean, I restored the entire evap case and flushed the evap.

A6 clutch components are luckily easy to replace. I'll have a new bearing in it. The friction surface appears to be metal on metal with some kind of dampening device up front. As little as I will probably end up driving the car it hopefully won't be a problem.

I assume you got the conversion shown below? And the switch in the upper right of the picture is the temp sensing switch? Is the "wire" connected to the switch the temperature probe?

[69 Limelight]

Yes to all questions. The “wire” on switch is actually a capillary tube with. Bulb on end and much longer than it appears. I mounted switch to existed case bolt on engine side of evaporator housing just below bracket in outlet tube. Hardly noticeable. Ran wires bottom of heater hose to back of right cyl head (secured with black wire ties-hardly noticeable) over to inside right valve cover where AC 2 wire harness is and spliced into compressor wire and wrapped entire harness and excess switch wire with factory type non sticky wire harness wrap-hardly noticeable. By evaporator “clean” I was referring to exterior fins not flushing internally.

[dataway]

Thank so much for the information, it will really help me make my decision.