Hi my 91' accords ac doesn't work and am wonder what should I look for as im pulling a vacuum. What are some things that will hold vacuum, but not pressure? Will the compressor seales hold vacuum, even if their bad? I googled a little and saw that shrader valves, o-rings, and a couple other things, will hold vacuum but not pressure. If the condensor is bad though it will not hold vacuum, correct?

 

While it's possible to have one way seals, it is difficult to say where they might occur. I have seen the shaft seal on a compressor leak one way (pressure to atmostphere) and not leak w/ internal vacuum. But generally, a vacuum test is a good test for integrity of the system.

If system is down, I would suggest a complete overhaul to avoid problems. I had a 90 EX and found the expansion valve orings leaked (dissimilar metals ( aluminum/brass) corrosion powder displacing orings). This was only leak I found. I later found same problem on 94 EX I currently have.

A pressure test (R134a+N2 to pressurize) is used by shops to find leaks w/ a e-sniffer. You could install 1/2 can of R134a and search for leaks if you have a sniffer. I've found it is not easy to find small leaks.

Removing evaporator is not difficult on 90-93 Accords.

You may want to retrofit if you can't find R12.

A good diy resource is autoacforum.com.

good luck

 

I have already started to retrofit the system, I have r134a adapters, I am starting to replace o-rings. I am starting to lean towards the compressor seals, mainly because last year I added a can of refrigerant and it leaked out in 3 days, it seemed to have leaked while it wasn't running. I came out side the next day to find my ac not working and oil on the ground. Could that be the shaft seal? I was going to replace the drier and compressor oil. So are the expansion valve o-rings a common leak point? Should I change those as well? I was planning on adding a can or so if r134a with dye and see where it is leaking. I have a black light and glasses so I should be able to see.

How long would you say it takes to remove the evaporator on these cars?

I also noticed my condenser had a lot of oily gunk in the bottom right hand corner, so I replaced those o-rings, but could the condensor be bad? if it is that wouldn't be a hard one to find a leak, because it is high pressure, correct? I also noticed on this car the o-rings where not green, I had a couple that are black and some were brown. Is that how r-12 was.

 

Regarding compressor. A leak should be evident by looking for a substantial oily, dirty ring around the compressor clutch rotation plane. As leakage occurs, oil is thrown out and slung off the clutch assy. Dirt accumulates on the oil. A slight coloration but dry ring is OK. I think this is rust/water that gets slung off in rain. Turning shaft of compressor while vacuuming may disclose a shaft seal leak.

Note, you can get a replacement shaft seal from ackits.com. If you decide to do this PM me for how to install the seal.

Expansion valve orings are very likely to be leaking. There are orings on expansion valve and pressure feedback tube. Replace all. Use Nylog or other oring prep lube to insure good seal. Polish sealing surfaces w/ very fine steel wool after cleaning off the corrosion materials.

Evaporator removal/replacement is probaly 1-2 hrs each way. If you don't have a Honda shop manual see Online Manuals links in DIY forum for a download manual (90-93 yrs are good). There will likely be trash in evaporator case which is another reason to remove.

Condensor can be damaged by rocks, but if oil/dirt is near the connection, the connection is more likely.

Most R134a rings are green, but some are black. HNBR is the type of rubber oring to use. ACkits has an oring kit for your car that will have good orings.

good luck

 

ok today I went to remove the compressor and 3 of the 4 bolts came right out. The 4th got stuck half way and now won't budge, so I left it and just replaced the o-rings and there was no oil in the compressor so I added some, then rotated the clutch.

How about this is there anyway the refrigerant could only leak when it is not running?

 

Yes the refrig can leak even without the ac system on.....

 

System pressure will always be there when not running. Pressure is approximately numerically same as temperature; 90F~90psi.

Was the bracket bolt head rounded, or the bolt was cross-threaded? Bracket should be OK w/ 3 bolts, so maybe just twist off if X-threaded. Heating engine at bolt entry point w/ a propane torch may help to release.

You need to keep up w/ how much lubricant is installed. You need ~ 8 oz in system before charging.

good luck

 

Im not too sure what is wrong with the bolt, I think it may have cross threaded, but I gave up and put everything back in changed the o-rings and added 4oz into the compressor. So you say 8oz in this system i'll just add the rest into the drier. Next i'll have to remove the evaporator and clean it and replace o-rings as well. I remember that when I ran the ac for those 3 days I had a smell so i'll clean it. The o-rings on the compressor where in really good shape surprisingly. I know that after I attempt to vacuum the system i'm going to add half a can of r134a with dye to see where the leak is and if it is simple or something like the condenser i'll fix it.

 

I would use compressed air to pop-flush the condensor. Pressurize w/ finger on outlet, allow pressure to build, and pop-release to blow out as much of mineral oil as possible. Same for evaporator when you have it out.

good luck

 

can I do it with the condenser in the car? And without removing the front bumper? Thanks for your feedback.

Wouldn't that also tell me if I have a leak in the condenser, because if there is a leak it will either make a noise, or not hold pressure to pop flush.