Help! RV2 compressor blew new shaft seal

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twister360

twister360

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I had a shop get the AC for my 74 Duster up and running. New hoses, expansion valve, and the compressor was gone through. They flushed the original evaporator and condenser and installed new drier. Held a vacuum with no problem, then charged with 134 with the proper oil and AC was working fine. I picked up the car and drove home 5 miles, AC working ok. Shut the engine off and notice the green dye dripping on driveway. Opened hood and I am sure shaft seal is leaking as the green fluid was all over the engine bay. Now the car will be out of commision for about a week while waiting on new seal from Arizona.

My question is what do you think was the reason for the failure? Overcharged, bad seal, bad shaft?

Thanks for your help. Gary
 
I'm told R12 rubber components can be "iffy" with 134. So not knowing? what they used? Might be wear on the shaft, this a rebuilt compressor?

I would not think that overcharge would affect the seal.

It is very probable that careless or improper installation could have condemned that seal
 
The front seal is a solid and made of carbon. I would check torque the small bolts around the end housing, and oil pan first. I changed a seal around 1980 and it still works today, but using r12.
 
The seal is metal and micro finished. If you replace it do not touch the seal surface, handle it on the side.
Post 3 should be done first to check for easy fix.
 
67Dart273 said:
I'm told R12 rubber components can be "iffy" with 134. So not knowing? what they used? Might be wear on the shaft, this a rebuilt compressor?

I would not think that overcharge would affect the seal.

It is very probable that careless or improper installation could have condemned that seal
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I had a member here be build my hoses with barrier hoses for 134and my compressor was rebuilt. I will have them very carefully check the shaft. I understand that you can run the seal if you handle it. You must coat in oil prior to installation.

Thanks. Gary
 
HI,

Is the system still holding R-134A and pressure? If so maybe just too much oil. An empty RV-2 system should be filled with about 10 OZ of oil. If the seal totally blew you will have lost the R-134A also. The problem now is to do anything you will have to recover the R-134A if it is still in there. Look in the factory service manual and it will show you how to make up a small dipstick and measure the oil level. The system must be discharged to do this.

Past that, I would replace the seal. As others have mentioned you can't touch the seal surfaces and handle them only on the edges. I also soak them in a container of oil over night before installing. You can replace the seal with the compressor mounted on the engine but, it is much more difficult to make sure things don't get off on an angle putting it together. It's better to have the compressor off and lying on its back. Check the shaft surface for smoothness and when you place the nose piece back in needs to be straight level and the bolts torqued down slowly and evenly side to side so the nose piece doesn't get cocked. The nose piece o ring should be coated with oil also.
 
Take it back to the shop that you paid to fix it.?
 
The crankcase and seal should be "at suction" pressure. That is, too much refrigerant or oil either one should not be an issue


The other thing is, with today's "poor parts" it may well be that some Chineseoated "engineer" came up with a 'less expensive' replacement seal design. I'm still betting on a "careless install." Who knows. Maybe "they" didn't even replace the seal
 
Suction pressure in a running system would be 25 to 30 pounds with R-12.With the system off , things will equalize to a static pressure which will depend on amount of system charge and ambient temperature. That static pressure could easily be 2 to 3 times the running pressure on the suction side. If the compressor sump is really overfilled with oil it may be up above the seal level and flooding the seal with more oil than it was ever intended to deal with.It doesn't take much of a seal leak to make a real mess, the clucth pulley slings the oil all over the place.

But, I agree, the most likely cause is the seal was not installed properly. I would bet today many shops have no idea how to service an RV-2 compressor. Most shops today simply replace the compressor if a seal leaks.

It's hard to find people around today who know how to deal with this 40+ year-old technology.
 
Pete in NH said:
static pressure could easily be 2 to 3 times the running pressure on the suction side. .
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I realize......and of course when off but with high underhood pressure.........what I was getting at is that too much oil or refrigerant should not be the cause, and pressure is "connected" IE the crankcase should not be an isolate trap of some sort. Not sure "flooding it with oil" should matter that much. Surely that oil is REALLY slung around in there. There is oil throughout the system.
 
The RV compressors are relatively unique in that they have an oil sump and a combination of pressure and splash lubrication much like an engine. There is a small rotor type oil pump driven by the crankshaft at the rear of the compressor. I don't think with the correct oil fill, the seal is actually under the sump oil level. Yes, there is oil flying around in there but, I don't think the seal sees all that much of it. the seal does depend on oil on it to keep it sealing properly which is why Chrysler wants you to run the A/C periodically in the winter.

The oil flying around I was referring to is oil being slung around the engine compartment once it gets past the seal and onto the clutch pulley. A little bit can make a big mess.

I guess we may learn what happened if the OP posts back after a new seal is installed.
 
Pete in NH said:
The RV compressors are relatively unique in that they have an oil sump and a combination of pressure and splash lubrication much like an engine. There is a small rotor type oil pump driven by the crankshaft at the rear of the compressor. I don't think with the correct oil fill, the seal is actually under the sump oil level. Yes, there is oil flying around in there but, I don't think the seal sees all that much of it. the seal does depend on oil on it to keep it sealing properly which is why Chrysler wants you to run the A/C periodically in the winter.

The oil flying around I was referring to is oil being slung around the engine compartment once it gets past the seal and onto the clutch pulley. A little bit can make a big mess.

I guess we may learn what happened if the OP posts back after a new seal is installed.
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The car is currently back at the shop that did the work and they are waiting on new seal. The mechanic has worked on these old Mopars for years and seems to be knowledgeable. He said he has done numerous 134 conversions, so hopefully he will get it figured out.

Pete
This is for my peace of mind, what type oil and how much? What should the gauges read on hi and low in a properly charged system?
 
twister360 said:
This is for my peace of mind, what type oil and how much? What should the gauges read on hi and low in a properly charged system?
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PAG oil is traditional w/ R-134A, but insure you use the correct viscosity for your compressor. PAO 68 is a new oil that is superior in several ways - doesn't absorb moisture like PAG, works for any required viscosity, works with R-12, R-134A, and HC refrigerants.
 
Got a call late today and car is ready.. I will pick it up tomorrow morning. The mechanic said there is no apparent reason for the seal failure, but all refrigerant had escaped. I hope it holds a charge for a long time! It's hot in south Louisiana.

Thanks. Gary
 
Hi Gary,

For an empty RV-2 system, I would use 10 to 11 oz. of something like BVA 100 ester glo. The oil is then compatible with both R-12 and R-134A. It also contains a U/V dye to help track down any future leaks.

Operating pressures would be around 25 to 28 pounds on the suction side with R-12 and a bit lower with R-134A. Discharge pressures really depend on ambient air temperatures and how hard the system is working removing heat, I would expect 125 to 225 pounds with R-12 and slightly higher with R-134A. R-134A does run at higher discharge pressures.

Good luck on the new seal, hope it holds for a long time.
 
Pete in NH said:
Hi Gary,

For an empty RV-2 system, I would use 10 to 11 oz. of something like BVA 100 ester glo. The oil is then compatible with both R-12 and R-134A. It also contains a U/V dye to help track down any future leaks.

Operating pressures would be around 25 to 28 pounds on the suction side with R-12 and a bit lower with R-134A. Discharge pressures really depend on ambient air temperatures and how hard the system is working removing heat, I would expect 125 to 225 pounds with R-12 and slightly higher with R-134A. R-134A does run at higher discharge pressures.

Good luck on the new seal, hope it holds for a long time.
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Well the system is still working and this is day 2, so maybe it will hold for a long time.

Thanks
 
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