A/C Service Port Schrader Valve Tool?
 

Anybody know where to obtain the tools to remove the schrader valves in the quick disconnect service ports on a 96 R-134A system? The high side valve core requires a smaller diameter tool than the low side. Located a tool to fit the low side valve core but have not located a source for the high side valve. Reason I ask is after adding R-134A I noticed both schrader valves leaking after disconnecting the couplers from the manifold gauge set. Thought I would check to see if they could be tightened a little before replacing them.

Yes, any and all auto parts stores and any bicycle store.:thumbs:

The valves will leak (a few little bubbles) This is normal!
The caps have an O-ring inside to finish the seal..
Steve :rofl:

The caps are to keep dirt out - they have nothing to do with the seal. If there are bubbles, you need to replace the schrader.

.....normal?..no it's not.....

..:iagree: :iagree:

For what it is worth, here is my opinion.
Even though bubbles are not a good thing to see at a schrader valve, there should be a good seal in the cap.
That seal in the cap should prevent leaking even though the schrader seal is not perfect, or you need a new cap.

I would put a new cap on it and put the schrader replacement on the list for when the A/C system needs major work.

I NEVER trust a schrader valve as the absolute seal -- regardless if it is a tire or the A/C system.
I consider the schrader valve as the mechanism to keep the "stuff" in there until I get a cap on it for a better seal.

Tom Piper

Ain't the design - in your car or home unit. You don't want dirt (or air for that matter) when you service the system. The cap is there to keep it out, and if you're anal about it, you use something like brake fluid cleaner before you attach the service hoses and once the can or drum is hooked up, you crack the connection (probably illegal) to purge air. Any leak, on the suction side particularly, needs to be dealt with. Most you don't see and the one's you do are larger than you might think.

All the replies are appreciated. Recharged the A/C this past weekend to tie the ribbons on finishing up a multi-part long term project and noticed both schrader valves bubbling just after removing the couplers. Thought I would check for tight first and bought one of those common combination schrader valve tools which has two sizes advertised to fit GM R-134A systems and only one size fit anything I have here, the low side. Am unable to check high side valve at the moment but the low side valve was tight; I might need to replace both valves. Incidentally, of my two original dust caps one is missing the internal rubber seal and I noticed a little pressure was released last night when I removed them again to check to see if the newly obtained tool would fit the schrader valves. I checked GM part numbers and apparently the dust caps are only available with the lines. What to do?

Greg, you can buy a kit containing the caps, small shraeder valves, and tool at AutoZone for around $6.

For this price, you probably could replace the entire system, but here it is.

http://www.jcwhitney.com/autoparts/P...017926/c-10101

Tom Piper

To get back on the subject: Auto parts store. Don't think those sold in bike shops have sufficient reach.

.....a few months ago, i discovered a high side shrader valve leak
(r-12) .....the high side shrader is a smaller valve and on my 88 it is RECESSED a lot farther into the bore......i purchased a master kit and discovered that the shrader tool i already had could remove the low side valve no sweat but, didn't fit the high side valve bore in DEPTH as diameter was fine.....the master kit was useless.....so, those seeking tools be careful that the hight side (r-12) extractor fiths the DEPTH of the bore!...since i own reclaim/recovery machines i removed the refrigerant and extracted teh valve core with a pair of tweezers and replaced, vacuumed, rechared and good to go!

I recharged my r134-A and when I removed the manifold kit my valve leaked bad.:willy: Actually sprayed. I couldnt get it to fully close, so rather than loose all freon I chose to just screw the cap on and let it go till it nolonger blew cold air. That was in spring, still got cold air.:hurray:

The moral of the story; the cap does have an oring seal. That seal works really well under most circumstances. I don't think a few bubbles a minute is enough to worry about. Finally when it stops blowing the cold...change the valves and recharge.:thumbs:

Thanks to Tom Piper for the link to the valve core service set. I wonder if this one will allow changing the valve without losing the charge? Muffin is right about standard schrader valve tools not reaching. The schrader valve cores in A/C systems are recessed more than conventional tools will reach so you need a longer reach tool. Also, the high side on mine is in a smaller bore than the low side valve so the tool to service GM high side valves needs to be smaller diameter than the low side tool.

....i though i just said that?..:D ....they make tools to remove the core W/O losing the charge but, like i said before, you will need a VERY long extractor to pul the shrader valve on the high side (R-12)....below is for the LOW side...
http://i27.photobucket.com/albums/c1...lMan/tool2.jpg

Oops... Sorry about that DaMailMan! You are correct; I meant to acknowledge your info but brain faded I guess. The tip is appreciated.

Update:

I was mistaken about the high side valve on my car. Upon closer inspection I see now it is actually not a schrader valve but rather a small rubbery composition ball of some kind in an inverted seat. I pecked at it a little and it stopped bubbling. I can't say for sure if my high side line is OEM or not but I think it is. I found some new plastic caps with seals at NAPA so maybe I am OK for a little while at least. I guess if the charge is eventually lost again maybe that would be a good time to revisit the service port valves. Thanks to all who contributed! :thumbs:

...no sweat!...just busting your chops a bit:thumbs: :cheers:

Interesting it is a ball valve instead of a schrader.

I seem to be in the minority here, but I have found the schrader valves are a poor ultimate seal -- notice how many others on this thread have said the schrader valves have leaked. It is common.
That is why I wouldn't get excited about just putting a new cap with a new seal on and let it that way. If the cap has a good seal, it will do the job in spite of the schrader.
As I stated before, to me the schrader is nothing more than a convenient way to keep from losing the charge until you get the valve cap on for a better seal.
The valve cap does keep out dust, but it has a much more important job.

Tom Piper

.....humnnn...ok, what happens when you have 200+lbs of pressure on a high side?...ya think the cap will keep it in or even stay on?...

Yes, even at 400.

Tom Piper

Leaking schrader valves might be fairly common. In making my rounds yesterday visiting the usual auto parts chain stores I noticed many featured R-134A displays up front along with other fast moving A/C supplies like refrigerants, oil, leak detecting dye, A/C system stop-leak, R-134 can with gauge & quickie low side charging hose and a rack full of blister pack schrader valves!

[IMG]http://i121.photobucket.com/albums/o...9412414_tp.jpg[/IMG]
The above is a schrader valve tool purchased recently at a bike shop in Ft. Lauderdale. I used it last week-end to tighten up the valve on my fuel rail.:thumbs:

......NO way......they are designed only to keep dust and dirt out...

.....i have one of these also but, that is good only for tightening or loosening...not good to replace a shrader w/out loosing the charge and if the shrader is leaking and is already tight, this is little good....

For an example, let's assume the cap has a flat end inside with the schrader valve that equates to 10% of a square inch.
At 400 Pounds Per Square Inch pressure inside the A/C system, there would be 10% of that, or 40 pounds of pressure, on the valve cap.

Tom Piper

.......sorry, don't buy it!....:nono:

I can't think of a single thing to add.

Tom Piper

96 LT1

I had to have my A/C evacuated and re-charged last month.

I tired adding 134 (thought system wasn't blowing cold enough) and the schrader valve wouldn't reseal. It continued to allow the 134 to spit out, even with the cap screwed on.

At the A/C shop, the owner told me he sees that problem very often. Seems that many times the valve won't re-seat, so it has to be changed.

So the remaining refrigerant in the system has to be released, system put on a vacuum pump, new valve installed, pressure tested and system recharged.

Cost me a couple of hundred $. I had to have it repaired since it was 100+F at the time.

Jake

.....neither can i.......:thumbs:

Unless that little rubbery butt plug failed completely I don't think the cap would ever see the full wrath of 200psi. While a small leak from that plug and the small volume between the plug and the cap itself could yeald higher pressures, I don't think it would blow it's cork.

...i DON"T agree.....:beatdeadhorse:

Actually, systems just blow up at the weakest part. There is a pressure relief valve on the rear of the head and the Nippo compressor seems to give up it's front seal rather easily. Otherwise, power is cut at 400 psi (you hope - no way to test some of the early switches). Point is that leaks you can see are leaking a lot (and maybe sucking something in when it's working).

Sorry, you are correct.:thumbs: