A/C out on the Cabota again...Arrrrrghh!

[PHPaul]

Last Spring (2016) on the first warm day I fired up the AC as it was getting pretty warm in that greenhouse of a cab and....pffffffft. Nada.

Hustled it up to the dealer and they fixed it tout de suite at no charge. Turned out it was a blown o-ring on the compressor, dumped the charge.

Doing a little grading on the driveway today, first 60° day of the year, turned on the AC and...squat. Popped the hood, and got the same visual I got last year: Dust built up in the oil around the fitting on the compressor, indicating another blown o-ring.

Various incantations and colorful descriptions of the situation ensued.

So now I have to decide whether to trailer it back up to the dealer (65 miles away) and get it fixed AGAIN, or order the o-ring and replace it myself and get a local guy to recharge the system.

 

[PHPaul]

No one else has had this issue?

 

[Tx Jim]

I wonder why o-ring is failing?

If it was my tractor I would get correct o-ring and replace it myself. Once AC system is opened up it needs to be evacuated to remove moisture & air from system. Then add the correct amount of coolant by monitoring both gauges.

 

[78Vette]

I wonder why o-ring is failing?

If it was my tractor I would get correct o-ring and replace it myself. Once AC system is opened up it needs to be evacuated to remove moisture & air from system. Then add the correct amount of coolant by monitoring both gauges.

Not to forget to add the proper amount of oil.

 

[tcrote5516]

Don't be discouraged by the lack of responses. Most of us are just angry that you have AC in the first place; how dare you complain about it

I would pull it apart yourself and take a close look at the ring and the fittings. Something may be buggered up on the mating surfaces that is causing the failures. The other option to consider is if a fitting actually needs to be there for future servicing needs. You may be able to just braze the connection removing the O ring from the equation entirely.

Make sure whoever evac's and refills the system has the correct specs for it.

 

[Lencho]

Not to pile on, but does it even get hot in Maine?
I am kidding of course! And I get the frustration of something not performing as designed. Does Kubota actually build the AC system or is it an outsourced component?

 

[lugbolt]

Kubota does the A/C just like most auto manufacturers. They buy the compressor, they build their own lines, they buy the evap and condensor, use a mitsuboshi belt and use Japanese wires. They were at one time making their own lines, though. Remember going through the factory in Georgia watching a guy crimping them; though I can't remember what equipment it was for.

 

[lugbolt]

Interesting that the O-ring is failing. Only a few reasons for it. What type of fitting is it? Did they use the proper O-ring? (Green?) Or did they use a generic black O-ring out of one of those O-ring kits that come from Timbuktu at the Chinese tool stores? A/C parts require special O-rings.

I'm thinking maybe that fitting is a flat part of the compressor with a recess for the O-ring. Could be that it's mismachined. Or perhaps the fitting itself (hose) is mismachined. Or warped from over-tightening? Something's definitely up. Throwing another O-ring on it may or may not fix it. They'll need to put some time into it to find the root cause of two failures.

 

[Tx Jim]

Not to forget to add the proper amount of oil.

May I ask why one would need to add oil especially if no oil happened to be present is present on exterior of fitting with failed o-ring & how much would you suggest adding?

Only accurate way I know of to add oil is drain/flush system & start from scratch to add recommended ounces of oil.

 

[tcrote5516]

May I ask why one would need to add oil especially if no oil happened to be present is present on exterior of fitting with failed o-ring & how much would you suggest adding?

Only accurate way I know of to add oil is drain/flush system & start from scratch to add recommended ounces of oil.

When the system is evac'd your removing all air from the system to ensure no moisture is left behind. If you just refill after fixing the seal, the small amount of moisture from the humidity in the air while the system was under no pressure will cause compressor failure.

So, when under vacuum everything will be removed from the whole system including the oil. The compressor for AC is no different from any other compressor in that it generates friction and needs oil to prevent wear. Some refrigerant has oil already in it (autozone ac charge kits) but the proper way is to get the manufacture specs, add the proper amount of oil and refrigerant.

 

[Tx Jim]

When the system is evac'd your removing all air from the system to ensure no moisture is left behind. If you just refill after fixing the seal, the small amount of moisture from the humidity in the air while the system was under no pressure will cause compressor failure.

So, when under vacuum everything will be removed from the whole system including the oil. The compressor for AC is no different from any other compressor in that it generates friction and needs oil to prevent wear. Some refrigerant has oil already in it (autozone ac charge kits) but the proper way is to get the manufacture specs, add the proper amount of oil and refrigerant.

I've never heard before that evacuating an AC system removes the oil. I've evacuated many AC systems without filling with oil afterward. Evacuation removes moisture & air but doesn't remove the oil.

 

[tcrote5516]

I've never heard before that evacuating an AC system removes the oil. I've evacuated many AC systems without filling with oil afterward. Evacuation removes moisture & air but doesn't remove the oil.

Sorry Jim, I was wrong. It's been a while since I've exercised the HVAC part of my brain so after your reply I did some more research. You are correct; unless the compressor is replaced you shouldn't have to add any oil.

Sorry for the bad advice!

 

[Tx Jim]

No problem thanks for correcting. As I age I make more mistakes than I should so I understand.
Jim

 

[mpham]

Haven't had a chance to try mine yet. If it does have a problem I will post back.

 

[PHPaul]

Thanks for all the feedback!

I have an appointment with a local mechanic that I trust to look at it tomorrow.

The first fix was at the dealer and we had to wait for the o-ring to arrive from a supplier so I assume (and we all know how that works...) that it was the proper material. I'm curious as to the reason behind the repeated failures as well.

Also, why is it fine all summer but craps out after going unused all winter? Drying out maybe? Should I make a point of cycling the AC on occasion in the winter?

I'll post back after the mechanic looks at it.

EDIT TO ADD:

For those folks with the tongue-in-cheek comments about needing AC in Maine:

1. Yes indeed, it DOES get hot, triple digit days in July and August are uncommon but do happen.

2. I've lived in Florida, South Carolina and the Philippines. There's a very good reason I live in Maine now: I HATE the heat! If it gets over 75 or 80 degrees, I'm miserable.

3. That cab makes a heck of a greenhouse. It can be 60° outside, but if the sun's out, it doesn't take long to hit 90° in a closed up cab with no AC.

 

[CountryBumkin]

I did some more research. You are correct; unless the compressor is replaced you shouldn't have to add any oil.

Having done a lot of AC work (automotive, R12 and R134a) I can tell you for sure that when refrigerant leaks out, the system usually loses oil too. And it doesn't always leave an oily stain - depending where the leak is. Mostly it depends on how fast the refrigerant was lost (how big the leak is).

Since you can't tell for sure how much, if any, oil was lost the best thing to do IMO is to flush the system (remove all oil and debris) then start fresh by adding the correct amount of oil, replacing the accumulator-receiver/drier, and then recharging with the correct amount of refrigerant.

In the systems I worked on, the various components (compressor, evaporator, condenser) each held some amount of oil so we would split up the the oil amount between these components (add some to each) before closing up the system, evacuating, and charging.

Maybe these newer tractors are different.

 

[PHPaul]

Picked the tractor up from the mechanic yesterday afternoon.

He said the o-ring was leaking again, and there was also a leak around the Schrader valve. Replaced the o-ring, cleaned the core of the Schrader valve and recharged. He's usually pretty thorough, so I assume he examined the seating surfaces of the ring, but didn't think to ask.

$110 where Kubota would likely have done it free under warranty, but got the tractor back in 8 hours and didn't have to make a 130 mile round trip or even two if I had to leave the tractor.

I'm happy, as long as it doesn't puke up the o-ring again.