Leon Speed

That's right, this car is impossible. I am certain that one of the design principles was, that in order to remove a simple part, what ever the part is, one must pull the engine first. Anyway.

I am deep into my TB and top-end refresh. Have everything off, clean, new parts, ready to go on. I noticed that the ATF cooler hoses are soft and brittle, so I want to rebuild them. They are crimped onto the hardlines, so these need to be removed as well. To remove the hardlines, one of the A/C hoses (the fat one curving towards the right fender) must be loosened. I tried to avoid removing the A/C compressor because of the sliding slope, but it seems there's no way around it.

The A/C hasn't been cooling for a while and I have new A/C o-rings, a new receiver/dryer and an new expansion valve.

So, here are my questions.

How do I discharge the A/C?

If I replace the A/C o-rings, a receiver/dryer and expansion valve, will they be okay for a few months without a new charge? I thought a new receiver/dryer shouldn't be exposed to air for too long.

I am skipping the compressor rebuild for now, need to get off the sliding slope.

Thanks!

dprantl

The proper way is to have someone with recovery equipment recover the refrigerant inside. Then you can open up the A/C system and do whatever work you need. When it is all back together, install a new drier and have the refrigerant recharged. Are you certain you must do this? Can you bend the A/C pipe slightly in order to get the ATF lines out?

Ok, I just noticed that you said the A/C has not been cooling for a while... do you have a gauge set you can hook up so you can see system pressures? Does the compressor engage when you turn the A/C on?

Dan
'91 928GT S/C 475hp/460lb.ft

Leon Speed

Can't bend the A/C pipe, it is massive. I don't have a gauge set, but I could see if I could get one. Worst case I need to call a mobile A/C guy to check and evacuate.

The compressor did work a few months ago. I forgot how to test it. Currently, with the TB job, the engine harnass is loose, so I can't test anything. Can I wire the battery directly to the compressor or will it go boom?

griffiths

If you can provide us some data on the ac system, such as:

1) Amount of R134a actually put into the system.
2) Did you use PAG or Ester oil and how much?
2) Was the system properly evacuated (pulled the correct vacuum) prior to charging?
3) AC System running say for 10 minutes, car in park, windows up and doors closed, fan speed at 1 or 2, ac temp set to 'max' cold,: at idle:
a) the high and low side pressures,
b) the outside air temp,
c) the center vent temp.

the flyin' scotsman

I replaced the short transmission oil cooler line without removing the a/c line.

I then removed the crimps and the old rubber replaced with new and clamps. I started a thread about this ...........long time ago though.

Alan

You can power the AC pulley clutch and see if it works - audible click (up close) and locks to compressor shaft - there is nothing else electrical to connect.

In stock config the clutch activating won't tell you that the compressor is good - but will eliminate failed upstream control gear.

If you just want to know if the system is charged test the refrigerant pressure switch (near dryer) - it needs pressure to be closed circuit, if its open circuit - you have a low charge (e.g. probably none)

Alan

Leon Speed

Thanks for the extensive questions, but I'm afraid I can answer these very quickly: I don't know! I haven't had the A/C serviced since I bought the car five years ago. The car doesn't run currently, I'm doing a TB and top-end refresh.

Leon Speed

Great, I'll look for it.

Leon Speed

Alan, can I connect the removed battery directly to the compressor? Or how else. The front engine harnass is disconnected and I don't want to fry anything.

Right! Thanks for that great tip. I'll try that.

dprantl

There is a black wire that comes out of the compressor. Apply +12V to that wire. The compressor will need to be grounded to something. If it is not bolted to the engine (or the engine is not connected to battery ground), you will need to connect a lead from its body to -12V at the battery. You should hear a pretty loud *click*. However, that will not tell you whether or not there is refrigerant in the system, which is what you really want to know before you start removing A/C components.

Dan
'91 928GT S/C 475hp/460lb.ft

the flyin' scotsman

now I think of it somemore if you have a small grinder you can probably split the crimps then pull off the rubeer hose, install new hose with clamps and tighten all while leaving the ends in situ

davek9

I think Alans suggestion is the bests for his situation and quick way to see if there is any pressure in the system.
Note: there are two switches at the dryer, the one you want is the lower one, the upper is for "frigerant Temp" Fan control and it should read open when cold

Leon Speed

"Good" news for once. The low pressure switch is open. I pressed the high pressure valve in and some refrigerant escaped, but the flow was very weak. It should be totally empty within a few seconds. That means I can take the system apart.

Leon Speed

That is my back up plan. But since I invested in yet another wrench to get the the hard lines (succesfully-yay!) separated near the cats, I am going to get this SOB out

Leon Speed

A/C is out. Years of crud and oil caked to it and to all hoses. Yuk! Now to rebuild the hoses and the ATF cooler hoses.

I pulled the ATF cooler and was very tempted to pull the condersor as well, but could quite figure out how it was attached to the lower chassis.

I couldn't get the ATF supply line to budge, so I cut off the crimp. That will need a clamp. Malcolm, any special clamp you used? I gather a clamp typemlike the ones for the fuel hoses.