AC Vacuum Pump and Oil

[Dynomite]

Originally Posted by VetteVet

Cliff,

Remove caps on drier and install it just prior to vacuuming the system. The hose on the left side(blue) is low side. The hose on the right side(red) is high side. If you look at the evaporator housing, the line going into the bottom is the high pressure line. Follow that one back and you will find the high side fitting. The one on the accumulator/drier is the low side fitting. Vacuum the system with both valves open. Charge the system by opening the low side valve only. This is especially important as the pressure developed when the compressor is running will rupture the can of freon. NEVER, EVER open the high side valve with the compressor running.

If you don't have one, you'll need to pick up a freon can valve from your local auto parts store.

Hook up the yellow hose to the middle connection on the gauge manifold and to the vacuum pump. Vacuum the system and then shut manifold valves first, then shut off pump. Let the sytem sit long enough to ensure that vacuum is not dropping. If it is, you have to find and fix the leak(s). If not, then diconnect the hose from the pump and hook up the can valve to the yellow hose. Prior to connecting the valve to the freon can, unscrew the valve stem fully(you will see the needle in the valve retract up into the body). Then screw the valve onto the can. Now turn the valve fully clockwise to puncture the can, then turn fully counterclockwise to open the valve. With the can upright, crack the fitting on the yellow hose where it attaches to the gauge manifold to purge the air out of the hose, then retighten it. You can now invert the can and crack the blue low side valve and charge until the pressure equalizes between the can and system(no more flow is felt or heard). Now start your car and set the climate control for Max cooling with blower on high. Ensure that the compressor clutch is engaged at this point. If not, you will have to pull the connector on the pressure cycling valve in the low side line and jumper it. The compressor clutch should now engage and you can charge the remainder of the first can with it in an upright position. Always charge with can upright when compressor is running. Once the first can is in, (you'll know it's all in when you can shake the can and not feel any liquid sloshing in it) you can shut the low side valve and swap to the second can. Remember to purge the yellow line again prior to charging. Continue this until you have added the correct amount of Freon, per the FSM. Once the sytem is fully charged, shut off the compressor and allow high and low side pressures to equalize before disconnecting the gauge manifold from the system. Once the manifold is disconnected, cap the high and low side fittings, reconnect the pressure cycling switch and you're done.

Jep

Jep....I can do this

Nice write up....appreciate it
I put all your information together in a single post if that is OK with you and if I understand the technical information correctly.......Evacuation and Re-Charging C4 ZR1 A/C System
Jep......... really appreciate you taking your time to explain this for us

I will go slow and practice vacuuming A/C and checking for leaks first. I think before I install new drier. Then vacuum the A/C system a second time after I know there are no leaks.

The 91' ZR-1 is running sooooo good it is unbelievable
With ALL the eliminated systems and with TB coolant removed LT5 Eliminated Systems.

The new technique of Eliminating Air from the coolant system worked perfectly for this refill of coolant Filling With Coolant and the Air Locked Water Pump.

Cliff

[Kevin]

I need to get my ac replaced in the spring when the car comes out of storage, wish I had someone local to help me but since I don't, off to the dealer it goes

[VetteVet]

Originally Posted by Dynomite

Jep....I can do this

Nice write up....appreciate it
I put all your information together in a single post if that is OK with you and if I understand the technical information correctly.......Evacuation and Re-Charging C4 ZR1 A/C System
Jep......... really appreciate you taking your time to explain this for us

I will go slow and practice vacuuming A/C and checking for leaks first. I think before I install new drier. Then vacuum the A/C system a second time after I know there are no leaks.

The 91' ZR-1 is running sooooo good it is unbelievable
With ALL the eliminated systems and with TB coolant removed LT5 Eliminated Systems.

The new technique of Eliminating Air from the coolant system worked perfectly for this refill of coolant Filling With Coolant and the Air Locked Water Pump.

Cliff

No problem, Cliff. Glad to be of assistance.

Golden Rules:
1) The better you vacuum the system, the better it will perform. You won't hurt the vacuum pump if you want to let it run for 5 hours.
2) Always purge the air from the charging(yellow) line when you connect a can of Freon.
3) When the compressor is running, always charge to the low(blue) side with can upright.
4) NEVER, EVER open the high side valve when the compressor is running. That flimsy Freon can will not contain the pressure(can you say SHRAPNEL!!!). I've never done it and don't want to try.

If you follow these rules, no harm will be done.

Jep

[scottfab]

This is great stuff.
To all who have contributed to this list THANKS!
I've been doing almost right for several decades.
The part I wasn't doing is in blue.
I made a few corrections to the text.
Printing this and putting it with the equipment.

Vacuum the A/C System
1. The A/C connector on the passenger side with black cap (just inside of shock) is High Side.
2. The A/C connector on the Accumulator/Drier is theLow Side.
3. Connect gauges to the Vacuum Pump (yellow line center of Manifold).
4. Connect Low Side (Blue Line) to Accumulator/Drier connection.
5. Connect High Side (Red Line) to High Side connection just inside passenger wheel well (lower line on Evaporator Housing).
6. Open both High Side and Low Side Manifold Valves and turn on Vacuum Pump for 60 minutes.
7. Shut Manifold Valves (then shut OFF Vacuum Pump) and make sure Vacuum does not leak down indicating a System Leak.
8. If NO LEAKS, Install New Accumulator/Drier and repeat this process.

Charge the A/C System
1. With both Manifold Valves closed, hook up a can of R12 to the yellow middle hose (see Note #1 below).
2. Turn the can valve fully counterclockwise to open the valve.
3. With the can upright, crack the fitting on the yellow hose where it attaches to the gauge manifold to purge the air out of the hose, then re-tighten it.
4. You can now invert the can and crack the blue Low Side valve and charge until the pressure equalizes between the can and system (no more flow is felt or heard). Never open the Red High Side valve during the Freon Charging process.
5. Now start your car and set the climate control for Max cooling with blower on high. Ensure that the compressor clutch is engaged at this point (see Note #2 below). You can now charge the remainder of the first can with can in an upright position. Always charge with can upright when compressor is running.
6. Once the first can is in, (you'll know it's all in when you can shake the can and not feel any liquid sloshing in it) you can shut the low side valve and swap to the second can.
7. Remember to purge the yellow line again prior to charging.
8. Continue this until you have added the correct amount of Freon, per the FSM. Once the system is fully charged, shut off the compressor and allow High Side and Low Side pressures to equalize before disconnecting the gauge manifold from the system.
9. Once the manifold is disconnected, cap the high and low side fittings, reconnect the pressure cycling switch and you're done.

2 Stage Vacuum Pump
Manifold and Gauges


Adapter Connections R134a to R12
.R12 Can Connector and Gauge


Notes:
1. Prior to connecting the valve to the freon can, unscrew the valve stem fully(you will see the needle in the valve retract up into the body). Then screw the valve onto the can. Now turn the valve fully clockwise to puncture the can.
2. If the compressor clutch is not engaged, you will have to pull the connector on the pressure cycling valve in the low side line and jumper it. The compressor clutch should now engage.

[scottfab]

Originally Posted by Dynomite

VetteVet is the contributor of All the Technical information. 4-cam recommended Accumulator/Drier replacement.

Yes, got that from reading the thread.

Originally Posted by Dynomite

I have no idea what "corrections" you made to the text?

I didn't think the corrections important enough to point out. It would seem unnecessarily rude. One correction could be instructive. The use of red in text defeats it purpose when printed in black and white. It shows up as light gray. I removed all unnecessary text embellishments in order to make it more readable. Some embellishments are good. Too many cause distraction and readability issues. This comes from over 20 years of exposure to and working with professional technical writers. But each to their own if it is their own.

Originally Posted by Dynomite

The description you printed out is not yet complete as there are more photos and details coming and VetteVet may add more technical input.

Complete enough to be useful as is.

Originally Posted by Dynomite

All those Details will be/are now in -Solutions- Evacuation and Re-Charging C4 ZR1 A/C System with thanks, appreciation and credit to VetteVet (Jep) and 4-cam noted

Yes, got that from reading the thread too.

Originally Posted by Dynomite

There are two related "How Tos" as these caused the loss of an evaporator which started this thread (Always tie back/secure the hoses to the A/C Evaporator when setting aside but not disconnecting the A/C compressor)

Think that was in the thread also.

[QUOTE=Dynomite;166506]1. Eliminated Systems.
Eliminated systems with TB coolant removed LT5 Eliminated Systems.

Was in the thread as well.

Originally Posted by Dynomite

2. Coolant Refill.
The new technique of Eliminating Air from the coolant system worked perfectly for this refill of coolant Filling With Coolant and the Air Locked Water Pump.

That's nice. I simply disconnect the driver side hose on the TB and point it up. The air all leaves from there as you fill the fluid. refilling the reservoir after one engine use, after it cools down, requires very little coolant.

Originally Posted by Dynomite

I talked with Marc Haibeck and he uses a similar technique of getting the air out (air locked Water Pump) using compressed air at certain times during the Coolant Refill. Ask Marc for Details Haibeck Automotive Technology.

Cliff

Thanks but I don't think I'll be bothering him with such things. It would be an unnecessary distraction for him.

[Dynomite]

Originally Posted by VetteVet

No problem, Cliff. Glad to be of assistance.

Golden Rules:
1) The better you vacuum the system, the better it will perform. You won't hurt the vacuum pump if you want to let it run for 5 hours.
2) Always purge the air from the charging(yellow) line when you connect a can of Freon.
3) When the compressor is running, always charge to the low(blue) side with can upright.
4) NEVER, EVER open the high side valve when the compressor is running. That flimsy Freon can will not contain the pressure(can you say SHRAPNEL!!!). I've never done it and don't want to try.

If you follow these rules, no harm will be done.

Jep

Hi Jep........I added your "Golden Rules" as Notes .......Evacuation and Re-Charging C4 ZR1 A/C System

I will let you know how it goes and post up after the first Evacuation. The first A/C System Evacuation to check for A/C System leaks. Then I will add the New Accumulator/Drier and Evacuate the A/C System a second time leaving the vacuum on for over an hour as you suggest....

This is getting exciting.....it is soooo much more fun knowing one can do these maintenance items themselves. And just have to mention........you Jep are a great teacher

Contributions like yours are what makes this Forum Exciting for guys like myself who enjoy the Mechanics and Technical aspects of the ZR-1 (LT5) and Corvette (L98) as much as driving them. Makes driving them all that much more fun

Note:
1. When you remove the LT5 from the ZR-1 by first removing the Plenum and A/C Compressor, before setting the A/C compressor aside on Drivers side wheel well.......secure the A/C lines going to the Passenger Side Evaporator so they do not move and break at the Evaporator.

Cliff

[Mystic ZR-1]

This would be a good time to ask how to switch over to 134a.
R12 is hard to get and $$$
Thanks!

[VetteVet]

Originally Posted by Mystic ZR-1

This would be a good time to ask how to switch over to 134a.
R12 is hard to get and $$$
Thanks!

This can be a tricky subject with lots of conflicting info available. Here is a "Cliff's Notes" type of guide:

http://autoacrepairs.com/134aConversion.htm

If you want to convert, I would recommend taking your car to a reputable shop that specializes in automotive AC repairs and pay them to do it. Once the conversion is done, then you can do your own maintenance and repairs from that point forward. Just bear in mind that there is a right way and a "quick and dirty" way. Make sure that the shop you are dealing with knows what they are doing. Expect your AC performance to take a hit, as R134a won't cool as well as R12.

Jep

[scottfab]

Originally Posted by Mystic ZR-1

This would be a good time to ask how to switch over to 134a.
R12 is hard to get and $$$
Thanks!

I did the conversion in 01.
It cost me about $250 for everything. Most of that ($180)
was for the rebuilt compressor and clutch assembly.
The dryer was surprisingly cheap.
I didn't put a label on the car stating R134a.
I did not inspect the orifice I just replaced it. (cheap)
I did not leak test it, just filled it and it worked.

After all was done, I loaded up on R134a cans at $4.99 ea.
They're up to about $10 now I see.

[Dynomite]

I am looking for a complete electrical schematic of the A/C system on a 90' and 91' (I assume they are the same) ZR-1.