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Quivering high side pressure Pages: 12

wptski on Sun August 18, 2013 8:23 PM User is offline

Year: 1990
Make: Buick
Model: Century
Engine Size: 3.3L
Refrigerant Type: R134A Conv.
Ambient Temp: 80
Pressure Low: 26
Pressure High: 160
Country of Origin: United States

OEM R-12, leaked static charge of 12oz after vacuum held, sniffer found shaft seal and manifold leaks. HR6 with new shaft seal/gaskets and new accumulator. No black death. Would have done a proper flush of the condenser and evaporator but couldn't loosen any of the fittings. Used POE oil as undecided to stay on R-12 or convert. Decided to try R-134A, static charge holds with sniffer finding no leaks.

Considering can/hose loss should be at 68% of R12 capacity with R-134A. I have 46F vent temperature still a bit undercharged(if there is such a thing with a conversion) but my high side pressure gauge quivers 5-10psi at idle with a fan in front of the condenser. Clutch stays engaged but did hear it drop out once but engaged again right away.

First time running with gauges connected so don't know if this was happening before.

Jag987 on Mon August 19, 2013 12:13 AM User is offline

Not totally sure what your question is other than the high side gauge quivers some. Put some more R134 in. On a conversion, the number I like is about 80% of what is called for in r12. For the temp, the pressure readings are lower than I would like to see. Are you charging this with 12oz cans or 30lbs jug and scale? Either way, your vent temp looks good so far.

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I bought a can of 134a at w**-mart that had a stop leak, oil, and dye in it. It also had a hose and a gauge, so now I'm an AC pro!

wptski on Mon August 19, 2013 9:02 AM User is offline

It's been a while since I've done any A/C work but this is the second in months. The other was on R-12 as well but I don't remember any quivering at all. Was just wondering if it was from something I did/didn't do or something with the compressor using the R-134A instead of R-12?

I'm using 12oz cans and a digital scale.

Speaking of cans or a jug for that matter. I bought a Mastercool 85510 can tap which looked a bit better than others as it has a check valve to prevent any pressure from comeing back into the can. I'm using R-12 manifold/gauges with adapters. The can adapter was threaded for a valve core so I installed one. The first can started off good but appeared to get very slow. I decided to remove the core, cracked opened the valve and nothing came out! Loosened the can tap itself and it hissed. Loosened the fitting at the can tap behind the check valve and it hissed. Had to run out and pick up one at AutoZone. Don't think the valve is holding good either. I was thinking of removing the check valve if possible but if the valve isn't holding that 4oz of R-134A that going to get vented. OMG! What if something like this happened on a 30lb jug? Possible???

Edited: Mon August 19, 2013 at 9:06 AM by wptski

mk378 on Mon August 19, 2013 10:10 AM User is offline

All can taps should have a check valve, it's important to keep the can from exploding in case someone makes a mistake and opens the high side to it. If working properly it won't interfere with normal use. They also all leak through the main valve when turned off. Once you tap a can you're pretty much committed to use the whole thing. If you end up with part of a can left over, leave the tapper connected to the yellow hose with the manifold valves closed, to try and trap refrigerant that leaks through the tapper.

wptski on Mon August 19, 2013 11:51 AM User is offline

Quote
Originally posted by: mk378
All can taps should have a check valve, it's important to keep the can from exploding in case someone makes a mistake and opens the high side to it. If working properly it won't interfere with normal use. They also all leak through the main valve when turned off. Once you tap a can you're pretty much committed to use the whole thing. If you end up with part of a can left over, leave the tapper connected to the yellow hose with the manifold valves closed, to try and trap refrigerant that leaks through the tapper.
That was the only one that listed a check valve and there is only place it can be. The A/C Pro brand I ran out and got lists nothing which is correct.

I added the valve core to my adapter for the reason you stated instead of using a hose/manifold or just a plug.

wptski on Mon August 19, 2013 2:35 PM User is offline

Looked at the MC can tap first today. Cranked on the shut off a bit more, it held and I removed the fitting. The check valve was a rubber ball held in by a brass retainer. So that kept what was left from just being vented! The A/C Pro can tap is threaded for a valve core.

Hardly any quivering today even before adding to the charge but if I raised the idle by hand, low side dropped, high would go to almost 200psi and the clutch would drop out which I assume was that the evaporator temperature got too low causing the switch to open.

After bring up the charge to 80% of R-12, low side is 28psi, high side is still 160psi and vent temperature is 45F. Raising the idle up now the clutch didn't drop out, high side went over 200psi and it was really racing fast at 225psi.

Should I quit now or add a bit more? Limits if any? I think that I've tread something a 250psi limit on a conversion but what are they referring to, at idle??

NickD on Mon August 19, 2013 3:48 PM User is offline

Have to add a 0.072 orifice to help with the idle drop out, Ford White. Safecracker old method is to sand your finger tips down, hold that on high pressure line and you can feel pulsations meaning you have gas in the system as opposed to a solid liquid. Would be seeing those pulsations on your gauge as well. Good old sight glass shows that.

Normal R-134a capacity is about 90% of R-12, major detriment is that tube and fin condenser that can't transfer the heat as well as a parallel flow condenser. Excessive cycling quickly wears out your clutch, puts undo stress on the compressor and the entire belt drive train for that matter. Switching besides the parallel flow condenser to a V-5 solves all of these problems, but creates mounting and electrical problems that also can be solved.

wptski on Mon August 19, 2013 4:13 PM User is offline

Quote
Originally posted by: NickD
Have to add a 0.072 orifice to help with the idle drop out, Ford White. Safecracker old method is to sand your finger tips down, hold that on high pressure line and you can feel pulsations meaning you have gas in the system as opposed to a solid liquid. Would be seeing those pulsations on your gauge as well. Good old sight glass shows that.

Normal R-134a capacity is about 90% of R-12, major detriment is that tube and fin condenser that can't transfer the heat as well as a parallel flow condenser. Excessive cycling quickly wears out your clutch, puts undo stress on the compressor and the entire belt drive train for that matter. Switching besides the parallel flow condenser to a V-5 solves all of these problems, but creates mounting and electrical problems that also can be solved.
I have no cycling at idle right now. If I add 4oz more would bring it to 90% but what do I jeopardize in doing so? Excessive high side pressure or what? What would I gain? The 7oz that added today only gained about 1F at the vent although the clutch doesn't cycle when the idle is raised now. The refrigerant carries the oil so the more refrigerant the more oil gets circulated.

My other vehicle that was R-12 had a vent temperature of 37.5F at idle but would cycle the clutch but not to the point of being excessive. I never checked it at above idle but it good and cold while driving. I sold it last week so can't retest anything.




Edited: Mon August 19, 2013 at 9:03 PM by wptski

wptski on Fri March 14, 2014 1:49 PM User is offline

Old post but same vehicle.

Finished the job and froze me out in max position. I don't think it's been driven since this time in August but not really sure. Got to loan it out to my nephew for a couple of weeks due to a minor winter slip/slide accident. It's on a trickle charger and started right up.

I was supposed to check under the vehicle for any fluids of any kind but didn't till after I left it running for five minutes or so. I notice a fair sized puddle of what I first thought was Prestone yellow on the garage floor. Popped the hood and it's right under the A/C compressor. I used the dyed POE from ACkits so I got my light/glasses and it is the POE oil. I did put the oil in the compressor before installing with plugs but the position it sits at caused me to lose some oil when I pulled the plugs out. It ran down, around, on top, etc. so I estimated the loss and put that into the accumulator. The floor does have some old oil resistant paint on so it always looks like more than it actually is.

I don't know if this happened slowly since August or quickly when I started it today. This could be from the spill I had when installed. The OEM R12 never showed up like this on the floor.

I'd be surprised that the shaft seal is leaking as I used a micron gauge while vacuuming the system which held for hours and hours. Has anyone seen a new shaft seal leak act like this?

Edited: Fri March 14, 2014 at 1:51 PM by wptski

TRB on Fri March 14, 2014 2:34 PM User is offlineView users profile

I have had shaft seals leak a few days later. You have to remember that replacing the seal does not fix a bent or damaged compressor shaft. No matter how slight the defect might be.

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wptski on Fri March 14, 2014 2:51 PM User is offline

I was thinking if it came from the original oil spill there wouldn't be any refrigerant in the oil. Used my TEK-Mate and didn't get a good hit! It's got the newer style sensor in it also which is supposed to be a lot better.

Will not be a happy camper if I have to pull it apart again?

Edited: Fri March 14, 2014 at 2:55 PM by wptski

mk378 on Fri March 14, 2014 5:26 PM User is offline

Refrigerant boils off almost instantly as it leaks out. You will only see the oil and dye. Clean up all the marks and see if any new ones appear. You could pull the clutch plate and inspect right at the seal.

wptski on Fri March 14, 2014 6:48 PM User is offline

Quote
Originally posted by: mk378
Refrigerant boils off almost instantly as it leaks out. You will only see the oil and dye. Clean up all the marks and see if any new ones appear. You could pull the clutch plate and inspect right at the seal.
I was rethinking that also but doesn't that mean that it leaked fast? I thought that a slow leak leaves the oil in the system but a fast one takes the oil with it?

Went back with a inspection mirror but couldn't see squat. Checked the pressure switch with a meter and it's open so at least it's below that amount. I'll throw down some cardboard tomorrow when I pull out of my garage and look from underneath.

Don't "think" that there is enough room to use a puller to get the plate off but I won't be able to try that for a couple of weeks when I get it back. You ever just get a bad seal or is always a bad shaft like TRB mentioned? I know the seal surface was clean, no rust as this has a plastic cover attached to the clutch plate plus the vehicle only has 20K on it and the odometer didn't roll over, family owned since new.


Edited: Fri March 14, 2014 at 6:52 PM by wptski

wptski on Sun March 16, 2014 1:54 PM User is offline

I was thinking before about a nitrogen setup and decided to go for it. Did a search here and came across this Thread . Look what "iceman2555" has to say about new shaft seal leakage. My new shaft seal which was lubricated has nowhere that amount of time on it but I wonder, does that mean that every new car off an assembly leaks from the shaft seal or what????

Edited: Sun March 16, 2014 at 2:00 PM by wptski

wptski on Mon March 17, 2014 11:51 AM User is offline

.....bump......

wptski on Fri March 21, 2014 8:50 AM User is offline

Don't know if my question is just being missed or just the fact that nobody wants to comment on what "iceman2555" stated in the linked thread above?

Jag987 on Fri March 21, 2014 10:03 AM User is offline

I think (I said I think) what iceman said was was stated and does not need any further explanation. Also, there are not many people thinking about Ac this time of year. That may be why there have not been any comments on here.

-------------------------
I bought a can of 134a at w**-mart that had a stop leak, oil, and dye in it. It also had a hose and a gauge, so now I'm an AC pro!

wptski on Fri March 21, 2014 10:42 AM User is offline

Quote
Originally posted by: Jag987
I think (I said I think) what iceman said was was stated and does not need any further explanation. Also, there are not many people thinking about Ac this time of year. That may be why there have not been any comments on here.
He stated that it's common for new shaft seals to leak. If so that should mean the it's common for newly assembled vehicle's A/C compressors to leak which is something I've never heard of before and never since I joined this forum. Seems like a key point to know after one installs a new shaft seal, don't you think?



Edited: Fri March 21, 2014 at 10:44 AM by wptski

wptski on Mon March 24, 2014 10:53 PM User is offline

Sorry but another bump here!

Just need to clarify/explain the link to a old thread mentioned four posts up where it's stated that it's common for a new seal to leak until it has 8-10 hrs on it. Never seen this mention in this forum since I joined. This should mean that a new vehicle should leak also. I know that on new vehicles the A/C comes on during defrost which would keep the seal lubricated but it won't cycle if it's too cold.

EDIT
May have to wait for "iceman2555" to show up again to explain his own post?

Edited: Tue March 25, 2014 at 11:31 AM by wptski

tomw on Thu March 27, 2014 7:14 AM User is offlineView users profile

I have an old Sable that came from the factory with a 'wick' mounted directly underneath the seal on the compressor. It leaked enough that I had a spot on my driveway. If they did not leak, they would not have put the wick on from the factory. I had them repair the leak as I figured if it leaked oil, it for sure would leak gas.
Of course, when they did the repair, they plopped the power steering pump on top of the intake and drizzled fluid all over the place. Took it in for drops on the drive and got it back drooling all over the place. Not happy.
I think seals will leak a bit until seated. The mfg figures they'll be sold and the seal seated before there is a problem. Perhaps they have improved sealing in the recent past. R U the ski on ford & escape sites?
tom

Add: The leak occurred after driving ~1700 miles from Indpls to SF Bay area, so the compressor was definitely broken in and the seal should have 'set' by then.

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simplificate and add lightness

Edited: Thu March 27, 2014 at 7:20 AM by tomw

Dougflas on Thu March 27, 2014 7:50 AM User is offline

if you think your shaft seal is leaking, place a plastic bag or shower cap around the front of the compressor overnight. Then poke a hole in the bag and stick your Tek-mate in it. If it sounds, you have a leak. Simple test.

wptski on Thu March 27, 2014 7:51 AM User is offline

Quote
Originally posted by: tomw
I have an old Sable that came from the factory with a 'wick' mounted directly underneath the seal on the compressor. It leaked enough that I had a spot on my driveway. If they did not leak, they would not have put the wick on from the factory. I had them repair the leak as I figured if it leaked oil, it for sure would leak gas.

Of course, when they did the repair, they plopped the power steering pump on top of the intake and drizzled fluid all over the place. Took it in for drops on the drive and got it back drooling all over the place. Not happy.

I think seals will leak a bit until seated. The mfg figures they'll be sold and the seal seated before there is a problem. Perhaps they have improved sealing in the recent past. R U the ski on ford & escape sites?

tom

Add: The leak occurred after driving ~1700 miles from Indpls to SF Bay area, so the compressor was definitely broken in and the seal should have 'set' by then.
The first I though, is that "tomw" from the Escape site?? Small world, hey?

Come to think of it, I had a '73 Blazer that had, well actually several leaks but one was way in the back which was refrigerant oil that dripped on the frame and ran back somewhere.

It's just that shaft seal leaks are so common and frequently mentioned here so it's common for a new seal to leak, why haven't I read about it earlier?

The OEM compressor didn't have any felt wipers but the new seal came with them so if the seal leak it would have to soak right through them as well. A seal may weep a bit, true but an A/C to way I understand it, a slow leak leaves the oil but a fast one doesn't so a new seal with a fast leak? Yipes!!

wptski on Thu March 27, 2014 7:56 AM User is offline

Quote
Originally posted by: Dougflas
if you think your shaft seal is leaking, place a plastic bag or shower cap around the front of the compressor overnight. Then poke a hole in the bag and stick your Tek-mate in it. If it sounds, you have a leak. Simple test.
The vehicle was in my garage where the leak was spotted then was pulled out and sat for several hours but didn't drip. Plus I checked the pressure switch and it's open so there may be nothing to push it out?

Too early in Michigan to get into this really deep just thinking ahead. One good thing is that this could have expensive loss of R12 but wasn't!

wptski on Mon April 14, 2014 12:33 PM User is offline

I'm confused now! I didn't have a nitrogen setup when a put this back together last summer but I do now. I put 150 psi on it yesterday and it didn't lose anything in almost 24 hrs. I now know that it's normal for a new shaft seal to leak when it's new but is it normal to hold pressure after that too???

wptski on Sun April 20, 2014 2:35 PM User is offline

Here it is a week later and it still held the N2! Is it common for a new seal the leak because it's not broken in and yet after that hold pressure which is even higher than the static pressure would be?

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