A/C servicing; vacuum, oil and charge system? (4 Viewers)

[2001LC]

Ok I'll try to give some color. But first above, I was just trying to test manifold to make sure no leaks in it (the manifold tool which has gauges). I was doing this with the vacuum pump attached to yellow hose from center of manifold. I guess that will not work by just closing all for valve to see if hoses hold vacuum.

I am reasonably sure I had vacuum pump pulling air from AC system. I had all four valves open.

I started with all valve closed. Opened both H & L on the manifold once I had vacuum pump on and pulling ~17in-hg.
Then opened the H & L valves that I had connect to AC system of vehicle, vacuum dropped to ~16in-hg.
I let pump run for 30 minutes.
Closed H & L on manifold and went from ~17in-hg to 0 in 5 seconds.

I vacuumed system a second time, same results.

I may well have crushed one or two O-rings of the three I worked with. I say this because the Dryer's nylon plug I sung up then tighten just a tad more. I could feel or though I felt the O-ring slip into it's tube seating pocket, then bottom out on the tad more. That tad more may have crushed it IDK.

On the discharge hose to discharge pipe O-ring (RH side of radiator), FSM calls for 16ft-lbf IIRC. But I do not have a 24mm crowsfoot, nor can I find one locally, to connect my torque wrench to, so did that by feel also.

The only other one I replaced (had off) was the suction hose to compressor fitting. That takes a 7ft-lbe torque, which I did use a torque wrench on.

So to pressurise I'll need to buy a tank filled with nitrogen that will fit the manifold on same yellow end as vacuum pump?
Can you point to where, what and how$???

Aslo I'll explain more soon, but I ran test again for one hour at 22in-hg (two 30 minute sets) with different vacuum pump. After run so long pulling vacuum with a possible leak, will a I need another new dryer?

Also the Denso Dryer I used is not the same part number you linked me above @flintknapper can you look above and tell; do you think I could have the wrong Denso Dryer?
Which may mean wrong fitting with O-ring.

Very long story short:
I had a defective vacuum pump from HF.
Also the wrong O-ring for suction hose to compressor. Seem we've and issue with the updated PN # at Toyota. There is 7 of old PN somewhere in Toyota system, which they'll have in a week. The current PN gives a pea size O-ring that in no way will fit.

 

[medtro]

I am confused here. Are there valves on the hoses you are closing or are you closing the side handles on the manifold. If you are closing the manifold gauges your hoses should be reading system pressure. If the vacuum pump had been running the system should be in a vacuum. If it goes to 0 that means there is a leak somewhere in the system. Did you pressurize it first with nitrogen to check for leaks? A leak can be anywhere in the system from the hose connection to the manifold to anywhere in the ac tubing. Ideally you leak check with positive pressure in the system. Something that goes from 22 inches of mercury to 0 in a hurry is probably a good sized leak that you can hear when pressured up. If you want to check the manifold hoses here is what I would do. Disconnect the manifold from the system. Close all the handles. Attach the refrigerant cylinder to the hose and open. Your gauge should read pressure. Use soap bubbles on the joints to look for leaks. Once that hose is done you can move to the other side and then finally the service hose.

I think he is saying, with the pump running and gauge shows ~22 in-hg, he closed:

• The valves to the H & L ports on the vehicle
• The valves on the gauge manifold

At this point, the pressure in the red & blue hoses and manifold should remain at 22 in-hg, but it went to zero fast.

If the hose connections are tight, then check the o-ring in those 3 hoses. Is the other port on the vacuum pump capped?

EDIT: A few minutes too late. Please see above post from @2001LC.

 

[2001LC]

I think he is saying, with the pump running and gauge shows ~22 in-hg, he closed:

• The valves to the H & L ports on the vehicle
• The valves on the gauge manifold

At this point, the pressure in the red & blue hoses and manifold should remain at 22 in-hg, but it went to zero fast.

If the hose connections are tight, then check the o-ring in those 3 hoses. Is the other port on the vacuum pump capped?

Yes it has a cap on it, never removed it at all.
Sorry guys I'm so tired I can't see any more. My thoughts are not coming across well.

 

[flintknapper]

Yes it has a cap on it, never removed it at all.
Sorry guys I'm so tired I can't see any more. My thoughts are not coming across well.

No trouble. Get some rest, gather your parts and let us know when you are ready to start again.

When you get your new vacuum pump (after filling with pump oil to correct level) you can test it by leaving the main valve shut and starting it. The gauge should show an immediate vacuum reading.

When you hook up your hoses to the A/C manifold (or any fitting) just get them finger tight. It is easy to crush/distort the O-ring (seal) such that it effectively blocks the hose. This often happens with a tool that is rented and has been used many times. Even new ones are easily over-tightened.

Then remember...after pulling a vacuum, to shut the manifold valves off while the pump is still running, so there is no chance of losing vacuum and introducing air back into the system.

Don't be discouraged...you've just experienced an equipment related set-back. Your procedure has been spot on.

 

[2001LC]

Thanks for that, it has been a discouraging week

Had parts failure with Stoptech SS brake lines as well, spending 8 hour trying to stop leaks. Finally gave up on those and drove over to Slee, picking-up their SS brake line. Solve that issue first try installing slee's.

I'll post the long story for your amusement in a moment. Seems we've a part number issue at Toyota with O-ring. The defective VP didn't help as I worked me way through without experience

But first, let me ask you; do you think:
I could have over tighten the Dryer plug crushing the O-ring in it?
With air leaking into system, presumably, and me pulling vacuum for extended period (over two hours). Should I replace AC system Dryer again?

Also you link me to a Dryer in earlier post 07 2007 Toyota Land Cruiser A/C Receiver Drier - Climate Control - Denso - PartsGeek which has a PN # (Part Number): Denso 24067-05169619. This is not PN # Advance Auto Parts sold me PN # Denso 478-1500 that I did use. Do I have the correct dryer more importantly plug with O-ring?


Note: I did close HIGH & LOW valves on manifold, before turning off vacuum pump.

 

[flintknapper]

I could have over tighten the Dryer plug crushing the O-ring in it?
Doubtful, but if in question....just pull and inspect it. It is possible to 'tear' an O-Ring if not lubricated prior to installation.

With air leaking into system, presumably, and me pulling vacuum for extended period (over two hours). Should I replace AC system Dryer again?
I don't think that was the issue, but IF you find that to be the case then yes, replace the desiccant bag. If you can find a bottle of 'Nylog' locally....I highly recommend using it to lube O-Rings and help seal fittings.

Also you link me to a Dryer in earlier post 07 2007 Toyota Land Cruiser A/C Receiver Drier - Climate Control - Denso - PartsGeek which has a PN # (Part Number): Denso 24067-05169619. This is not PN # Advance Auto Parts sold me PN # Denso 478-1500 that I did use. Do I have the correct dryer more importantly plug with O-ring?

Denso 478-1500 shows to be compatible with your vehicle (98-2007), so that shouldn't be a problem.


Note: I did close HIGH & LOW valves on manifold, before turning off vacuum pump.

Good Man! It's all going to work out. Just hang in there.

^^^^^^ Expand for replies

 

[2001LC]

^^^^^^ Expand for replies

View attachment 1698211

Thanks. I did use Denso oil on all O-ring, but will see if I can get some Nylog.

To clarify: "With air leaking into system, presumably, and me pulling vacuum for extended period (over two hours). Should I replace AC system Dryer again?"
"I don't think that was the issue, but IF you find that to be the case then yes, replace the desiccant bag."

Are you saying if I find leak at Dryer plug, then replace with new kit?

Also: Can you give direction on what tank/tool, fitting and filler (air) I should buy and from where, to use to pressurize system to check for leaks?

 

[white_lx]

Sorry to hear you have a combination of issues which can be a bit of a disappointment. I'm not sure if a new vacuum pump needs to be broken in. The vanes usually wear round and the rounded over edges improve the sealing to the housing. Never had the 'luxury' of a brand new pump.

To test the pump + manifold you can place the quick couplers on the manifold stubs. That way any leakage from the couplers is excluded during the testing. Next pull a vacuum with the manifold valves open and the quick coupler valves closed.

Also: Can you give direction on what tank/tool, fitting and filler (air) I should buy and from where, to use to pressurize system to check for leaks?

My first attempt would be to replace that faulty o-ring and pull a vacuum to see if that solved your problem. If solved, I would just pull a long vacuum and leave the dryer.

If you wanted to test with pressurized air and you are replacing the dryer, you could fill the system with air from your compressor. As long as your air supply is clean. (btw. I have never replaced a dryer, just pulled very long vacuums).

So you need to adapt from an air fitting to the ACME thread. Which is not trivial. I don't think you will be able to find an adapter from NPT to ACME (not legal). But if such a thing exists, I'd like to know.

Option 1: if you have an old or a low cost R134a service line, you can cut the hose and install a hose barb and adapt to an air fitting.

Option 2: If you can temporarily remove the fitting from your vacuum pump you may be able to connect your air line to that fitting.

Option 3: Use the following series of fittings:

1. an NPT air fitting, followed by
2. NPT->1/4 JIC hydraulic fitting such as JIC 4M x 1/4 NPTM Connector | JIC Male to NPT Male - Straight | JIC to NPT | Hydraulic Adapters & Fittings | Hydraulics | www.surpluscenter.com
3. An R12->R134A adapter, such as FJC-6014 Amazon product ASIN B0002JMF98

Now you can connect your compressor to the service line of the manifold. Technically the JIC has a wrong taper angle (37degrees). ASME flare (R12) fittings are 45 degrees. But because of the internal o-ring it will work. You could also look for an ASME flare / NPT fitting, but I was unable to find one locally.

I modified the flare angle of a JIC fitting to 45 degrees (I like machining things):

Rest assured that after all this you should have enough tools and knowledge to tackle any AC job.....

 

[flintknapper]

Thanks. I did use Denso oil on all O-ring, but will see if I can get some Nylog.

To clarify: "With air leaking into system, presumably, and me pulling vacuum for extended period (over two hours). Should I replace AC system Dryer again?"
"I don't think that was the issue, but IF you find that to be the case then yes, replace the desiccant bag."

Are you saying if I find leak at Dryer plug, then replace with new kit?
If you find a significant leak there...then you were pulling moisture laden air (depending on the humidity there) directly across the desiccant bag. How MUCH moisture would be absorbed is debatable. You 'could' pull a vacuum for an extended period of time and probably be O.K. but remember the desiccant 'absorbs' moisture and it will be tough to remove. Its not like you are boiling off free standing moisture in the system. But I leave that up to you. Professionals would replace it if there was any doubt.

Also: Can you give direction on what tank/tool, fitting and filler (air) I should buy and from where, to use to pressurize system to check for leaks?

You can rig up a hose any number of ways to use compressed air (clean) and do it that way. Nitrogen would be ideal...but who has a bottle of Nitrogen laying around. Was your A/C system working correctly before you removed the compressor? The sudden loss of vacuum (if the system had actually been evacuated) would point to either a major leak or an issue with a connection.

I would double check everything, hook it back up....pull a vacuum for 15 minutes and see if it holds. If it does...we are good to continue pulling a 'deep' vacuum on it. IF not..then the source of the leak needs to be found. If the 'equipment' is not found to be the source...then we would want to pressurize the system and look for leaks there.

^^^^ Expand

 

[2001LC]

Was a week of bad parts and tool.

While I'm waiting on a new O-ring (from old PN#) to see if I can then hold pressure. I'll locate and price a nitrogen filled tank and adapter. I suppose I'll need a regulator for tank as well?

I'll weight cost of tooling up, with having a Dealer or corner AC shop find leak.

There is one part more that has been troubling me, as I think about my run of bad parts. The Denso Drier I purchased was sealed in a clear plastic bag, not near the long term type package the OEM was sealed in. The bag had deep and well defined impression of the drier in center on plastic bag. I thought this impression a little strange, as drier moved freely in bag filled with air when I got it. But impression only along center of bag

My thinking is Denso vacuum packed drier in bag, and it held firmly in one spot creating the impression of Drier over time. That over time, air bleed into the bag, allowing Drier Desiccant to now move freely in bag. This may indicate moisture in Desiccant, which is of concern. But also it may indicate this box sat on a shelf for many years.

So my second concern is the O-ring of plug may have shrunk from loss of plasticizer leaching out of rubber. This may be a second leak I'm dealing with.

I'm thinking more than one leak from the three O-rings I replaced (not considering other location yet). Because, as I hooked up new VP which is pulling 22.5 in-hg (opposed to 16 in-hg of bad pump) for 30 minutes. Also replacing O-ring with old and one other not PN # for location, but size looked about right. The 22.5 drop to 0 in-hg over 90 seconds now. With other O-ring I had in on first test, that was for sure to small and a bad VP. I saw 16 to 0 in-hg in 3 seconds. So I don't know if change of smaller to larger or to old O-ring just slowed that leak or stoped it. And possibly I've another one.

So my question is the Denso bag holding the Drier being full of air normal or should vacuum in bag have held? Edited, I looked at another Denso drier. It was the same. They may be vacuum packed, but aren't by the time we get them.

If not I'll replace it as well.

 

[abuck99]

You can throw the dessicant in the oven on 225-250 for about 12hrs. Remove and dry in airtight container. (Or buy another and keep that one and throw it in your gun safe)

Google reactivating dessicant bags.

 

[2001LC]

I just asked Denso tech that very question, He couldn't say. I've a small 40 gram Desiccant made to be reactivate. 2 hours at ~250 F in oven, and it changes color. But I'd have an issue as old Desiccant and now new one to lesser extent, have Denso oil on them. My GF will killing me if I put in the oven... Stinky oil!

Currently I'm not really to concerned with Desiccant, but that of O-ring that came with it. I'm just guestoning if this packaging was indicating it's been on shelf a long time. So, I spoke with Denso Tech. He couldn't say whether vacuum packed or nitrogen or why bag had impression. But he did decipher date code on box. It's from Sept 2017. So not very old with respect to O-ring.

 

[white_lx]

I'll locate and price a nitrogen filled tank and adapter. I suppose I'll need a regulator for tank as well? I'll weight cost of tooling up, with having a Dealer or corner AC shop find leak.

Yes, you would need a regulator (with ~100 psi max regulated pressure to make sure you can not over-pressurize the system by accident). On top of that you would still need one of the above options 1-3 to connect the manifold. If you want to go through all these trouble you can also consider:

Option 4: After you replace the faulty o-ring, pull a vacuum and charge the system with one can of R134A. If you think there still is a leak, then you can use a low cost (Amazon/Ebay) leak detector to find the leak. A lot cheaper than acquiring the N2 equipment and also easier to locate a leak.

Option 5: If you can find a used can of refrigerant, you drill and glue in a fitting and connect the modified can to the service line of the manifold.

You can throw the dessicant in the oven on 225-250 for about 12hrs. Remove and dry in airtight container. (Or buy another and keep that one and throw it in your gun safe)
Google reactivating dessicant bags.

I believe the desiccant bags in A/C systems contain molecular sieve, not silica gel. (Silica gel can be regenerated easily but it does not retain the moisture enough for an A/C system and could release it.) If indeed molecular sieve, you would need to heat to a min of around 300F and pull a vacuum or N2 purge to remove the moisture from the desiccant.

 

[abuck99]

Yes, you would need a regulator (with ~100 psi max regulated pressure to make sure you can not over-pressurize the system by accident). On top of that you would still need one of the above options 1-3 to connect the manifold. If you want to go through all these trouble you can also consider:

Option 4: After you replace the faulty o-ring, pull a vacuum and charge the system with one can of R134A. If you think there still is a leak, then you can use a low cost (Amazon/Ebay) leak detector to find the leak. A lot cheaper than acquiring the N2 equipment and also easier to locate a leak.

Option 5: If you can find a used can of refrigerant, you drill and glue in a fitting and connect the modified can to the service line of the manifold.



I believe the desiccant bags in A/C systems contain molecular sieve, not silica gel. (Silica gel can be regenerated easily but it does not retain the moisture enough for an A/C system and could release it.) If indeed molecular sieve, you would need to heat to a min of around 300F and pull a vacuum or N2 purge to remove the moisture from the desiccant.

Ahhha ok- makes sense. Thank you for explaining the differences.

 

[2001LC]

I've just order one more Denso Drier.

Watched a video of a shop that just used a rubber tip HP air outlet (which I have) to blow compressed air in AC through yellow line. I've also a moisture trap for my compressor. Once I've correct O-ring I'll try that, if leak persists.

Using HP air and just tossing in a new Denso Drier Desiccant when done, saves time and money.

 

[medtro]

You can also reinstall your old drier and then use compressed air to find leak. Fix the leak, reinstall "new" drier you removed earlier.

 

[flintknapper]

So my second concern is the O-ring of plug may have shrunk from loss of plasticizer leaching out of rubber. This may be a second leak I'm dealing with.

Nylog is your friend.

Nylog Sealant (P/N RT201B)(BLUE)

 

[2001LC]

I suppose I could swap in old drier. Thanks for suggestion.

I played with manifold some more today, it may be leaking.

As I said I got and improvement after installing old O-ring, but still not holding. But also, I can't get manifold to hold either. I close valves at ends of red and blue hoses, while just hanging on manifold holders. I pull vacuum of 22.5, close manifold valves, drops to 0. I played around swap hoses and over tightening fittings. Got 25 in-hg, and took to longer to drop to 0. loosened fitting while pulling 25in-hg to introduce leak, and see 22.5in-hg.

I'm picking up new manifold tomorrow to compare. Also a third VP just in case.

 

[flintknapper]

I suppose I could swap in old drier. Thanks for suggestion.

I played with manifold some more today, it may be leaking.

As I said I got and improvement after installing old O-ring, but still not holding. But also, I can't get manifold to hold either. I close valves at ends of red and blue hoses, while just hanging on manifold holders. I pull vacuum of 22.5, close manifold valves, drops to 0. I played around swap hoses and over tightening fittings. Got 25 in-hg took to longer to drop to 0. loose fitting while pulling 25in-hg to introduce leak, and see 22.5in-hg.

I'm picking up new manifold tomorrow to compare. Also a third VP just in case.

^^^^^ Is this per chance Harbor Freight stuff? If so....yes, check it, double check it and when your done still be suspicious.

 

[2001LC]

Ok. I really need to stop buying any tools with moving parts from HF (Harbor Freight).

I have the second replacement HF VP (vacuum pump) which uses less oil than first (more than it should) and pulls a better vacuum.
I have the second replacement HF manifold gauge set, which leaks less than first.
I have the 30ml of Nylog blue label, from local HVAC wholesaler.

To give HF manifold best chance to seal. I cleaned all threat and seals that are accessible. I then smeared a little Nylog on each seal, before attaching hoses to manifold, VP and H & L AC valves. Making sure all hoses and valves sung, I ran VP with AC H & L valve closed and just hung on manifold. With manifold valves open it reached ~27in-hg just in manifold hoses. I then close manifold valves and then turn off VP. Vacuum slowly went from ~27 to ~2 in-hg. I turned VP back on leaving all valves closed. Vacuum then went from ~2in-hg to ~27in-hg. So must be manifold itself is leaking internal at minimum. JUNK!

But I figured, I could still pull vacuum on system regardless of manifold leak. So I put my old factory O-ring (the larger of the two I removed) back into AC compressor coated with Nylog.

I then ran VP for 10 minutes with all valves of manifold connected an open.
I then closed AC H & L valves, then manifold valves, turned off VP and disconnected hoses/valves from my H & L of AC system.
Letting my truck's sit for 30 minutes. After which I reconnected manifold gauge to check if vacuum held, it seem to have reading ~22in-hg.

So now I ran VP drawing for ~1 hour from my AC system, reaching 27in-hg. At elevation of 5,300 ft ASL, 70 F.
Closed all valves & disconnected manifold from my AC system with manifold low gauge reading 27in-hg.
Let sit overnight.

This morning manifold gauge read ~2in-hg, I cleared to ~0. Then them connected to my systems AC. My systems AC now reads 27in-hg.

I'm pulling vacuum now to really drier out well for the day, checking and adding oil to VP each hour. I'm no longer concerned with state of new Denso drier, as it wasn't drawing air from drier O-ring or discharge O-ring. It most likely was leaking at compressor O-ring. So I had some concern I may have pull some oil from AC system. So I added 1/2 oz more of Denso oil to compressor, when I put in old O-ring with Nylog.

I've the engine coolant & radiator out of vehicle at the moment, so I'll not be starting engine. I'll just wait on new AC compressor O-ring from Toyota and a replacement radiator. I'l keep AC system sealed for maybe ~5 days, which will make a good long term test of my AC system.

Meantime I'm returning HF junk, and either give them one more try or get a VP and manifold gauge set elsewhere. Anyone care to recommend a good manifold and vacuum pump?

BTW: I priced a nitrogen tank... wow.... $250 for 60lb tank. I can buy a lot of Denso drier desiccant for that! I'll go with HP air if need be.